Merge pull request #3976 from nrobi144/feat/desktop-live-media

feat(desktop): NIP-53 live streaming — consume & discover
2026-10-05 19:28:25 +00:00 · 2026-08-24 09:19:34 -04:00
parent dad7fccaf2 1190b55dbf
commit 78acc61318
19 changed files with 2208 additions and 33 deletions
@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.nip53LiveActivities
+
+import com.vitorpamplona.quartz.nip53LiveActivities.streaming.tags.StatusTag
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+/**
+ * Pure, CLI-safe ranking + freshness logic for NIP-53 live activities, shared by Amethyst Android
+ * and Amethyst Desktop so both platforms order live streams identically (no drift).
+ *
+ * Everything here operates on **primitives / pre-snapshotted values** rather than reading mutable
+ * event or online-checker state. This is deliberate: the sort keys (status-after-online-check and
+ * `current_participants`) can be mutated by background work mid-sort, and reading them lazily inside
+ * a comparator makes the ordering unstable — TimSort then throws
+ * *"Comparison method violates its general contract!"*. Callers must snapshot the keys into a
+ * [LiveActivityRank] once, before sorting.
+ */
+object LiveActivitySorting {
+    /** Status ordering used across the discover feed, the live bar and profile streams. */
+    const val ORDER_LIVE = 2
+    const val ORDER_PLANNED = 1
+    const val ORDER_ENDED = 0
+
+    /** How recently a `status=live` 30311 must have been re-published to count for the live bar. */
+    const val LIVE_BAR_FRESHNESS_SECONDS = 15 * 60L
+
+    /** Grace after a planned `starts` before it is treated as "overdue / never went live". */
+    const val OVERDUE_PLANNED_GRACE_SECONDS = 60 * 60L
+
+    /**
+     * Maps a live-activity status to a sort bucket. A `status=live` stream whose `.m3u8` is known to
+     * be offline right now ([isOfflineNow]) is downgraded to [ORDER_ENDED] so dead streams sink.
+     */
+    fun statusOrder(
+        status: StatusTag.STATUS?,
+        isOfflineNow: Boolean = false,
+    ): Int =
+        when (status) {
+            StatusTag.STATUS.LIVE -> if (isOfflineNow) ORDER_ENDED else ORDER_LIVE
+            StatusTag.STATUS.PLANNED -> ORDER_PLANNED
+            StatusTag.STATUS.ENDED -> ORDER_ENDED
+            null -> ORDER_ENDED
+        }
+
+    /**
+     * True when a stream should surface in the per-column "live now" bar: it is `status=live`, its
+     * `.m3u8` is not known-offline, and the 30311 was (re)published within [freshnessSeconds]. A host
+     * is expected to re-publish the 30311 continuously while live, so a stale one is a zombie.
+     */
+    fun isLiveAndFresh(
+        status: StatusTag.STATUS?,
+        createdAt: Long,
+        now: Long = TimeUtils.now(),
+        isOfflineNow: Boolean = false,
+        freshnessSeconds: Long = LIVE_BAR_FRESHNESS_SECONDS,
+    ): Boolean = status == StatusTag.STATUS.LIVE && !isOfflineNow && createdAt >= now - freshnessSeconds
+
+    /**
+     * True when a `status=planned` stream's start time has passed by more than the grace window and
+     * it never flipped to live — used to relabel / downrank stale "starts in…" cards.
+     */
+    fun isOverduePlanned(
+        status: StatusTag.STATUS?,
+        startsAt: Long?,
+        now: Long = TimeUtils.now(),
+        graceSeconds: Long = OVERDUE_PLANNED_GRACE_SECONDS,
+    ): Boolean = status == StatusTag.STATUS.PLANNED && startsAt != null && startsAt < now - graceSeconds
+
+    /**
+     * A pre-snapshotted set of comparator keys for one live activity. Build one per item **before**
+     * sorting; never read live event/online state inside the comparator.
+     */
+    data class LiveActivityRank(
+        val statusOrder: Int,
+        val followParticipants: Int,
+        val totalParticipants: Int,
+        val startOrCreated: Long,
+        val idHex: String,
+    )
+
+    /**
+     * Descending comparator (best first): live > planned > ended, then more participating follows,
+     * then more total participants, then more recent start/creation, then id for a stable tiebreak.
+     */
+    val RANK_DESCENDING: Comparator<LiveActivityRank> =
+        compareByDescending<LiveActivityRank> { it.statusOrder }
+            .thenByDescending { it.followParticipants }
+            .thenByDescending { it.totalParticipants }
+            .thenByDescending { it.startOrCreated }
+            .thenByDescending { it.idHex }
+
+    /**
+     * Snapshots each item's rank **once** via [rankOf], then sorts. Because the keys are captured up
+     * front, [rankOf] may read volatile state (online cache, `current_participants`) safely — the
+     * comparator only ever sees the immutable snapshot, so TimSort's contract holds.
+     */
+    fun <T> sortDescending(
+        items: Collection<T>,
+        rankOf: (T) -> LiveActivityRank,
+    ): List<T> {
+        val snapshot = items.associateWith(rankOf)
+        return items.sortedWith { a, b -> RANK_DESCENDING.compare(snapshot.getValue(a), snapshot.getValue(b)) }
+    }
+}
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.nip53LiveActivities
+
+import com.vitorpamplona.amethyst.commons.nip53LiveActivities.LiveActivitySorting.LiveActivityRank
+import com.vitorpamplona.quartz.nip53LiveActivities.streaming.tags.StatusTag
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class LiveActivitySortingTest {
+    private val now = 1_000_000L
+
+    @Test
+    fun statusOrderRanksLiveOverPlannedOverEnded() {
+        assertEquals(LiveActivitySorting.ORDER_LIVE, LiveActivitySorting.statusOrder(StatusTag.STATUS.LIVE))
+        assertEquals(LiveActivitySorting.ORDER_PLANNED, LiveActivitySorting.statusOrder(StatusTag.STATUS.PLANNED))
+        assertEquals(LiveActivitySorting.ORDER_ENDED, LiveActivitySorting.statusOrder(StatusTag.STATUS.ENDED))
+        assertEquals(LiveActivitySorting.ORDER_ENDED, LiveActivitySorting.statusOrder(null))
+    }
+
+    @Test
+    fun offlineLiveIsDowngradedToEnded() {
+        assertEquals(
+            LiveActivitySorting.ORDER_ENDED,
+            LiveActivitySorting.statusOrder(StatusTag.STATUS.LIVE, isOfflineNow = true),
+        )
+    }
+
+    @Test
+    fun isLiveAndFreshRespectsFreshnessWindow() {
+        // published just now -> fresh
+        assertTrue(
+            LiveActivitySorting.isLiveAndFresh(StatusTag.STATUS.LIVE, createdAt = now, now = now),
+        )
+        // published 20 min ago -> stale (default 15-min window)
+        assertFalse(
+            LiveActivitySorting.isLiveAndFresh(StatusTag.STATUS.LIVE, createdAt = now - 20 * 60, now = now),
+        )
+        // fresh but offline -> excluded
+        assertFalse(
+            LiveActivitySorting.isLiveAndFresh(StatusTag.STATUS.LIVE, createdAt = now, now = now, isOfflineNow = true),
+        )
+        // planned is never "live and fresh"
+        assertFalse(
+            LiveActivitySorting.isLiveAndFresh(StatusTag.STATUS.PLANNED, createdAt = now, now = now),
+        )
+    }
+
+    @Test
+    fun overduePlannedDetectedAfterGrace() {
+        // starts 2h ago, still planned -> overdue
+        assertTrue(
+            LiveActivitySorting.isOverduePlanned(StatusTag.STATUS.PLANNED, startsAt = now - 2 * 60 * 60, now = now),
+        )
+        // starts in the future -> not overdue
+        assertFalse(
+            LiveActivitySorting.isOverduePlanned(StatusTag.STATUS.PLANNED, startsAt = now + 60 * 60, now = now),
+        )
+        // no start time -> not overdue
+        assertFalse(
+            LiveActivitySorting.isOverduePlanned(StatusTag.STATUS.PLANNED, startsAt = null, now = now),
+        )
+        // live is never "overdue planned"
+        assertFalse(
+            LiveActivitySorting.isOverduePlanned(StatusTag.STATUS.LIVE, startsAt = now - 2 * 60 * 60, now = now),
+        )
+    }
+
+    @Test
+    fun sortOrdersByStatusThenFollowsThenTotalThenTime() {
+        val endedFresh = rank(LiveActivitySorting.ORDER_ENDED, follows = 5, total = 5, time = now, id = "a")
+        val liveFewFollows = rank(LiveActivitySorting.ORDER_LIVE, follows = 1, total = 1, time = now - 100, id = "b")
+        val liveManyFollows = rank(LiveActivitySorting.ORDER_LIVE, follows = 3, total = 3, time = now - 200, id = "c")
+        val planned = rank(LiveActivitySorting.ORDER_PLANNED, follows = 9, total = 9, time = now, id = "d")
+
+        val items = listOf(endedFresh, liveFewFollows, planned, liveManyFollows)
+        val sorted = LiveActivitySorting.sortDescending(items) { it }
+
+        // live (most follows) > live (fewer) > planned > ended
+        assertEquals(listOf(liveManyFollows, liveFewFollows, planned, endedFresh), sorted)
+    }
+
+    @Test
+    fun sortBreaksTiesByTotalThenTimeThenId() {
+        val a = rank(LiveActivitySorting.ORDER_LIVE, follows = 2, total = 10, time = now, id = "aaa")
+        val b = rank(LiveActivitySorting.ORDER_LIVE, follows = 2, total = 20, time = now, id = "bbb")
+        val c = rank(LiveActivitySorting.ORDER_LIVE, follows = 2, total = 20, time = now + 50, id = "ccc")
+
+        val sorted = LiveActivitySorting.sortDescending(listOf(a, b, c)) { it }
+        // higher total first (b,c over a); newer time breaks b vs c
+        assertEquals(listOf(c, b, a), sorted)
+    }
+
+    @Test
+    fun sortIsStableUnderConcurrentKeyMutation() {
+        // Simulate a background online-check flipping a stream's status mid-sort: rankOf reads a
+        // volatile source, but sortDescending snapshots once, so no TimSort contract violation.
+        val ids = (0 until 200).map { it.toString().padStart(3, '0') }
+        var flips = 0
+        val sorted =
+            LiveActivitySorting.sortDescending(ids) { id ->
+                // Alternate the status bucket every read; if the comparator read this lazily it would
+                // be inconsistent and throw. Snapshotting protects us.
+                flips++
+                val order = if (flips % 2 == 0) LiveActivitySorting.ORDER_LIVE else LiveActivitySorting.ORDER_ENDED
+                LiveActivityRank(order, 0, 0, now, id)
+            }
+        assertEquals(ids.size, sorted.size)
+    }
+
+    private fun rank(
+        statusOrder: Int,
+        follows: Int,
+        total: Int,
+        time: Long,
+        id: String,
+    ) = LiveActivityRank(statusOrder, follows, total, time, id)
+}
@@ -0,0 +1,150 @@
+# Manual Testing Sheet — Desktop Live Media (NIP-53) v1
+
+**Plan:** `docs/plans/2026-08-20-feat-desktop-live-media-plan.md`
+**Branch / worktree:** `feat/desktop-live-media` · `.claude/worktrees/feat-desktop-live-media`
+**Run:** `./gradlew :desktopApp:run`
+
+Acceptance test for the whole v1 feature. Each section is tagged with its current build state so you
+know what will actually work today:
+
+- **🟢 LIVE** — built & compiling; test it now.
+- **🟡 PARTIAL** — built but with a known gap (called out inline).
+- **⚪ PENDING** — not built yet; skip until its commit lands.
+
+**Legend for results:** ✅ pass · ❌ fail (write what happened) · ⏭️ skipped/blocked
+
+---
+
+## Setup (do once)
+- [ ] Open **<https://zap.stream>** in a browser — this shows who is live on Nostr right now with real
+      kind-30311 streams + kind-1311 chat. Keep it handy as your source of truth.
+- [ ] Log into Amethyst Desktop with an account that **follows ≥1 host who streams** (follow a couple of
+      the zap.stream front-page hosts if not).
+- [ ] Confirm relays are connected (no persistent "offline" banner).
+- [ ] (For later zap tests) connect an NWC wallet under **Wallet**.
+
+> **Tip:** live streams come and go. If a section says "nobody is live," check zap.stream — if the front
+> page is also empty, wait for a stream to start rather than recording a failure.
+
+---
+
+## 1. Discover → "Live now"  🟢 LIVE
+
+Open the **Discover** destination. Scroll to the **LIVE NOW** section (below the featured pack hero).
+
+| # | Step | Expected | Result |
+|---|------|----------|--------|
+| 1.1 | Open Discover with ≥1 stream live on the network | A **LIVE NOW** section appears with a red dot header + a search box + a grid of cards | |
+| 1.2 | Look at card order | **Live** streams first, then **planned** ("starts in…"), then ended; within live, streams where **more of your follows** participate rank higher, then higher **viewer count** | |
+| 1.3 | Inspect a live card | Shows thumbnail image, a red **LIVE** badge, the **title**, the **host** name, and **"N watching"** when the host reports a viewer count | |
+| 1.4 | Inspect a planned card | Shows a **"in 2h / in 30m / SCHEDULED"** badge instead of LIVE | |
+| 1.5 | Type a host's name in the search box | Grid filters live to matching streams as you type | |
+| 1.6 | Type part of a stream **title** | Filters to matching titles | |
+| 1.7 | Type a **hashtag** that a live stream uses (e.g. `bitcoin`) | Filters to streams tagged with it | |
+| 1.8 | Type gibberish (`zzzzz`) | Shows **"No live streams match "zzzzz.""** (grid empty, section still visible) | |
+| 1.9 | Clear the search | Full ranked grid returns | |
+| 1.10 | Open Discover when **nothing** is live network-wide | The LIVE NOW section is **absent** (not an empty box) | |
+| 1.11 | **Known gap:** click a card | Nothing happens yet — the watch screen isn't wired (see §3). Not a bug today. | |
+
+---
+
+## 2. Per-column "live now" bar  🟢 LIVE
+
+| # | Step | Expected | Result |
+|---|------|----------|--------|
+| 2.1 | Open a **Following** feed column while a **followed** host is live | A compact pinned bar sits at the **top of that column**, above the feed: red dot + **"<host> is live"** | |
+| 2.2 | Have **2+** followed hosts live at once | The bar shows the **most-watched** one, plus a **"+N live ›"** link | |
+| 2.3 | Click **"+N live ›"** | A dropdown lists all currently-live streams in scope; each entry is clickable | |
+| 2.4 | Open a **Global** feed column | The bar reflects the **global** live set (typically different/larger than Following) | |
+| 2.5 | Scroll the feed | The bar stays **pinned** at the top (doesn't scroll away) and the feed scrolls smoothly beneath it | |
+| 2.6 | Open a column where **nobody in scope** is live | **No bar** is shown (Following bar hidden when no followed host is live) | |
+| 2.7 | Open a **hashtag / list / search / notifications** column | **No bar** (by design — v1 scopes the bar to Following + Global only) | |
+| 2.8 | **Known gap:** click the bar / a dropdown entry | No-op today (watch screen pending, §3) | |
+
+---
+
+## 3. Watch screen — player + chat + zap  ⚪ PENDING
+
+*Not built yet. These are the target checks for when the watch commit lands; skip for now.*
+
+### Open / layout
+- [ ] Clicking a live card or the bar opens a **full-window** watch screen: video **left**, chat **right**, host/metadata below.
+- [ ] Header shows title, host (avatar + name), participant roles, viewer count, and a **LIVE** pill.
+- [ ] Closing returns to the prior view and **stops playback**.
+
+### Video (live)
+- [ ] The live stream plays (audio + video).
+- [ ] **No seek bar** in live mode (a "● LIVE" pill instead).
+- [ ] Play/pause, volume, fullscreen work.
+- [ ] Kill the source briefly → **"Reconnecting…"** (not a frozen frame) → recovers, or an **offline + Retry** state if it stays down.
+- [ ] Opening an already-offline stream → offline placeholder, never an endless spinner.
+
+### Video (VOD / recording)
+- [ ] An **ended** stream with a recording plays the recording with a **normal seekable** bar.
+- [ ] An ended stream with **no recording** shows "Stream ended — no recording" (non-playable).
+
+### Chat (read)
+- [ ] Kind-1311 messages for this stream appear, newest at bottom.
+- [ ] Auto-scrolls to newest **only while at the bottom**; scrolling up shows a **"↓ N new"** pill.
+- [ ] Hovering chat pauses auto-scroll; leaving resumes.
+- [ ] **Muted/blocked** users' messages don't appear; muting mid-stream hides existing ones immediately.
+- [ ] A busy stream stays smooth (messages may batch slightly).
+
+### Chat (post)
+- [ ] Sending posts a kind-1311 with the correct stream `a` tag (verify it shows on zap.stream).
+- [ ] Composer is **disabled with a reason** when logged out / no relays / stream ended (draft preserved).
+
+### Zap
+- [ ] **Zap** the stream → amount dialog → sends via NWC; receipt attributed to the 30311.
+- [ ] Zap **disabled with reason** when the host has no lightning address or no NWC wallet is connected.
+- [ ] *(Per-message chat zap + top-zappers leaderboard are v1.5 — not expected.)*
+
+### Lifecycle / re-entry
+- [ ] Host edits title/participants mid-stream → header updates live.
+- [ ] Stream ends mid-watch → "ended" banner, composer disabled, "Play recording" offered; window does **not** auto-close.
+- [ ] Opening a **second** stream tears down the first cleanly (no double audio, no leaked chat).
+- [ ] Opening via a direct **naddr/nevent** link resolves + loads; unknown → clear message, no hang.
+
+---
+
+## 4. Profile "Streams" tab  ⚪ PENDING
+- [ ] A streaming host's **profile** has a **Streams** tab listing their live + past streams.
+- [ ] A live entry opens the watch screen; a past one with a recording plays VOD.
+
+## 5. Planned streams  🟡 PARTIAL
+- [ ] Planned streams show a **"starts in…"** badge in the Discover grid.  🟢 (works now)
+- [ ] A planned stream whose start passed long ago and never went live is relabeled/downranked.  ⚪ (pending online/overdue wiring)
+- [ ] *(No "Remind me" in v1 — badge only, by design.)*
+
+## 6. Online-probe / dead streams  ⚪ PENDING
+- [ ] A `status=live` stream whose `.m3u8` is actually dead is **not** shown as live (sinks/hidden).
+      *Today all `status=live` are treated as online — this downgrade is not wired yet.*
+
+---
+
+## 7. Cross-cutting / security & regression  🟡 PARTIAL (mostly pending)
+- [ ] ⚪ App only plays `https` stream URLs; `file://`/`smb://`/custom-scheme URLs are refused (incl. the "open in default player" fallback).
+- [ ] ⚪ No drive-by HEAD probing of every cached stream URL (probe only what's needed for visible cards).
+- [ ] ⚪ Chat messages with bidirectional/control unicode render without reordering surrounding UI.
+- [ ] 🟢 Existing feed video (NowPlayingBar) still works; existing feeds/Discover unaffected by the new section.
+- [ ] 🟢 `./gradlew :commons:jvmTest --tests "*.LiveActivitySortingTest"` passes.
+- [ ] ⚪ Full build green: `./gradlew :desktopApp:compileKotlin :amethyst:compileDebugKotlin` + `spotlessApply` clean.
+
+---
+
+## Platform notes
+- **macOS** (AVFoundation): primary target for the video tests.
+- **Linux** (GStreamer): must be installed at runtime; live-HLS reconnection differs — spot-check when watch lands.
+- **Windows** (Media Foundation): weakest native live HLS — the stall watchdog/reconnect must carry it.
+
+## Known v1 limitations (by design — not bugs)
+No broadcasting; no audio rooms / raids / clips; no per-message chat zap or leaderboard (v1.5); no OS
+notifications / "Remind me" (badge only); live bar only on Following + Global columns.
+
+---
+
+### Quick "test right now" path (today's build)
+1. `./gradlew :desktopApp:run`, log in, ensure ≥1 stream is live (check zap.stream).
+2. **Discover → LIVE NOW**: see the grid, confirm ranking (§1.2), try search (§1.5–1.9).
+3. **Home → Following** and **Global**: confirm the pinned live bar + "+N live ›" (§2).
+4. Everything in §3–§7 marked ⚪/🟡-pending is expected **not** to work yet — that's the next build.
@@ -2359,6 +2359,23 @@ fun MainContent(
            com.vitorpamplona.amethyst.desktop.ui.media
                .GlobalFullscreenOverlay()

+            // Full-window NIP-53 live watch overlay (player + chat), opened from any live surface
+            // via LiveWatchController.
+            val watchAddress by com.vitorpamplona.amethyst.desktop.ui.live.LiveWatchController.current
+                .collectAsState()
+            watchAddress?.let { addr ->
+                com.vitorpamplona.amethyst.desktop.ui.live.LiveWatchScreen(
+                    address = addr,
+                    cache = localCache,
+                    relayManager = relayManager,
+                    account = account,
+                    onClose = {
+                        com.vitorpamplona.amethyst.desktop.ui.live.LiveWatchController
+                            .close()
+                    },
+                )
+            }
+
            // Snackbar for zap feedback
            SnackbarHost(
                hostState = snackbarHostState,
@@ -28,6 +28,7 @@ import com.vitorpamplona.amethyst.commons.model.UserContext
 import com.vitorpamplona.amethyst.commons.model.cache.ICacheEventStream
 import com.vitorpamplona.amethyst.commons.model.cache.ICacheProvider
 import com.vitorpamplona.amethyst.commons.model.cache.LargeSoftCache
+import com.vitorpamplona.amethyst.commons.model.nip53LiveActivities.LiveActivitiesChannel
 import com.vitorpamplona.amethyst.commons.model.nip88Polls.PollTallyPolicy
 import com.vitorpamplona.amethyst.commons.service.nwc.NwcPaymentTracker
 import com.vitorpamplona.quartz.nip01Core.core.Address
@@ -57,6 +58,8 @@ import com.vitorpamplona.quartz.nip47WalletConnect.events.LnZapPaymentResponseEv
 import com.vitorpamplona.quartz.nip51Lists.bookmarkList.BookmarkListEvent
 import com.vitorpamplona.quartz.nip51Lists.bookmarkList.OldBookmarkListEvent
 import com.vitorpamplona.quartz.nip51Lists.followList.FollowListEvent
+import com.vitorpamplona.quartz.nip53LiveActivities.chat.LiveActivitiesChatMessageEvent
+import com.vitorpamplona.quartz.nip53LiveActivities.streaming.LiveActivitiesEvent
 import com.vitorpamplona.quartz.nip57Zaps.LnZapEvent
 import com.vitorpamplona.quartz.nip57Zaps.LnZapRequestEvent
 import com.vitorpamplona.quartz.nip65RelayList.AdvertisedRelayListEvent
@@ -65,6 +68,7 @@ import com.vitorpamplona.quartz.nip88Polls.response.PollResponseEvent
 import com.vitorpamplona.quartz.nipB7Blossom.BlossomServersEvent
 import com.vitorpamplona.quartz.utils.DualCase
 import com.vitorpamplona.quartz.utils.Log
+import com.vitorpamplona.quartz.utils.cache.LargeCache
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.DelicateCoroutinesApi
@@ -90,6 +94,16 @@ class DesktopLocalCache : ICacheProvider {
    val users = LargeSoftCache<HexKey, User>()
    val notes = LargeSoftCache<HexKey, Note>()
    val addressableNotes = LargeSoftCache<String, AddressableNote>()
+
+    /**
+     * NIP-53 live-stream channels (kind 30311), keyed by address value. This is the FIRST channel
+     * cache on Desktop (the base app has none — [getAnyChannel] historically returned null). It is a
+     * strong-ref [LargeCache] (not soft) because a channel owns its live chat (kind 1311) notes and
+     * must survive GC while a stream is on-screen; chat growth is bounded instead by
+     * [LiveActivitiesChannel.pruneOldMessages] (cap 500), triggered from [consumeLiveActivityChat].
+     */
+    val liveChatChannels = LargeCache<String, LiveActivitiesChannel>()
+
    private val deletedEvents = ConcurrentHashMap.newKeySet<HexKey>()

    /** NIP-hints index accumulated from consumed events (event/address/pubkey → relay). */
@@ -130,6 +144,8 @@ class DesktopLocalCache : ICacheProvider {
    val metadataVersion: StateFlow<Long> = _metadataVersion.asStateFlow()

    companion object {
+        /** Cap on retained kind-1311 chat messages per live channel (matches [Channel.pruneOldMessages]). */
+        const val MAX_CHAT_MESSAGES_PER_CHANNEL = 500
    }

    /** Index of notes by author pubkey — for fast metadata invalidation */
@@ -279,8 +295,13 @@ class DesktopLocalCache : ICacheProvider {
    ): Boolean {
        if (!wasVerified && !justVerify(event)) return false
        val consumed = route(event, relay)
-        // Write-through to local store, but skip if event came from local store (hydration)
-        if (consumed && relay != com.vitorpamplona.amethyst.desktop.relay.LocalRelayStore.LOCAL_RELAY_URL) {
+        // Write-through to local store, but skip if event came from local store (hydration). Live
+        // chat (kind 1311) is deliberately NOT persisted: a busy stream's chat is unbounded and
+        // replaying it on next launch is pointless (the stream is over) — only the 30311s hydrate.
+        if (consumed &&
+            relay != com.vitorpamplona.amethyst.desktop.relay.LocalRelayStore.LOCAL_RELAY_URL &&
+            event !is LiveActivitiesChatMessageEvent
+        ) {
            localRelayStore?.enqueue(event)
        }
        return consumed
@@ -364,6 +385,14 @@ class DesktopLocalCache : ICacheProvider {
                consumePollResponse(event, relay)
            }

+            is LiveActivitiesEvent -> {
+                consumeLiveActivity(event, relay)
+            }
+
+            is LiveActivitiesChatMessageEvent -> {
+                consumeLiveActivityChat(event, relay)
+            }
+
            else -> {
                false
            }
@@ -797,6 +826,88 @@ class DesktopLocalCache : ICacheProvider {
        return true
    }

+    // ----- NIP-53 live activities (kind 30311 streams + kind 1311 chat) -----
+
+    /**
+     * Bumped whenever a live-stream (30311) is added/updated so the Lives discovery grid and the
+     * per-column "live now" bar can recompute their snapshot. Chat (1311) does NOT bump this — chat
+     * updates flow through the channel's own notes flow, and a new message never changes stream
+     * ranking, so bumping here would cause needless full-grid recomputes on busy streams.
+     */
+    private val _liveActivityVersion = MutableStateFlow(0L)
+    val liveActivityVersion: StateFlow<Long> = _liveActivityVersion.asStateFlow()
+
+    fun getOrCreateLiveActivityChannel(address: Address): LiveActivitiesChannel =
+        liveChatChannels.getOrCreate(address.toValue()) {
+            LiveActivitiesChannel(address)
+        }
+
+    /**
+     * Consumes a kind 30311 live streaming event. Replaceable, so the newest per-address copy wins
+     * (stored in [addressableNotes] like other addressables) and is attached to the address's
+     * [LiveActivitiesChannel]. Returns true so it write-throughs to the local relay store (30311s are
+     * cheap and bounded — hydrating them on next launch shows the last-known streams instantly).
+     */
+    private fun consumeLiveActivity(
+        event: LiveActivitiesEvent,
+        relay: NormalizedRelayUrl?,
+    ): Boolean {
+        val address = event.address()
+        val addressableNote = getOrCreateAddressableNote(address)
+
+        val existing = addressableNote.event
+        if (existing != null && existing.createdAt >= event.createdAt) return false
+
+        val author = getOrCreateUser(event.pubKey)
+        addressableNote.loadEvent(event, author, emptyList())
+        relay?.let { addressableNote.addRelay(it) }
+
+        val channel = getOrCreateLiveActivityChannel(address)
+        channel.updateChannelInfo(author, event, addressableNote)
+
+        _liveActivityVersion.value++
+        return true
+    }
+
+    /**
+     * Consumes a kind 1311 live chat message and attaches it to its stream's channel (by the root
+     * `a` tag). The channel's chat is capped at 500 newest messages via [pruneOldMessages] so a busy
+     * stream can't grow memory unbounded. Unlike 30311, chat is NOT persisted to the local relay
+     * store (see [consume]) to avoid unbounded chat replay on next launch.
+     */
+    private fun consumeLiveActivityChat(
+        event: LiveActivitiesChatMessageEvent,
+        relay: NormalizedRelayUrl?,
+    ): Boolean {
+        val note = getOrCreateNote(event.id)
+        if (note.event != null) return false
+
+        val author = getOrCreateUser(event.pubKey)
+        note.loadEvent(event, author, emptyList())
+        trackNoteAuthor(note, event.pubKey)
+        relay?.let { note.addRelay(it) }
+
+        val activityAddress = event.activityAddress() ?: return true
+        val channel = getOrCreateLiveActivityChannel(activityAddress)
+        channel.addNote(note, relay)
+        if (channel.notes.size() > MAX_CHAT_MESSAGES_PER_CHANNEL) {
+            channel.pruneOldMessages()
+        }
+        return true
+    }
+
+    /**
+     * Snapshot every known live-stream channel that currently carries a 30311. Driven by
+     * [liveActivityVersion] for reactive recomputation (mirrors [snapshotFollowPacks]).
+     */
+    fun snapshotLiveActivities(): List<LiveActivitiesChannel> {
+        val out = mutableListOf<LiveActivitiesChannel>()
+        liveChatChannels.forEach { _, channel ->
+            if (channel.info != null) out.add(channel)
+        }
+        return out
+    }
+
    /**
     * Snapshot all 39089 (FollowListEvent) addressable notes currently in cache.
     * Use [followPackVersion] to drive reactive recomputation.
@@ -921,8 +1032,13 @@ class DesktopLocalCache : ICacheProvider {
    // ----- Channel operations -----

    override fun getAnyChannel(note: Note): Channel? {
-        // Desktop doesn't support channels yet
-        return null
+        // Only NIP-53 live channels exist on Desktop today. Resolve a 1311 chat message or a 30311
+        // stream note back to its channel; everything else has no channel.
+        return when (val event = note.event) {
+            is LiveActivitiesChatMessageEvent -> event.activityAddress()?.let { liveChatChannels.get(it.toValue()) }
+            is LiveActivitiesEvent -> liveChatChannels.get(event.address().toValue())
+            else -> null
+        }
    }

    // ----- Deletion tracking -----
@@ -1015,6 +1131,7 @@ class DesktopLocalCache : ICacheProvider {
        users.clear()
        notes.clear()
        addressableNotes.clear()
+        liveChatChannels.clear()
        deletedEvents.clear()
        _followedUsers.value = emptySet()
        followerCounts.clear()
@@ -70,6 +70,7 @@ import com.vitorpamplona.amethyst.desktop.followpacks.subscribeMetadataFor
 import com.vitorpamplona.amethyst.desktop.model.DesktopIAccount
 import com.vitorpamplona.amethyst.desktop.network.RelayConnectionManager
 import com.vitorpamplona.amethyst.desktop.ui.ZapFeedback
+import com.vitorpamplona.amethyst.desktop.ui.live.LivesSection
 import com.vitorpamplona.quartz.nip51Lists.followList.FollowListEvent
 import kotlinx.coroutines.launch
 import java.awt.Toolkit
@@ -86,6 +87,10 @@ fun DiscoverScreen(
    onNavigateToProfile: (String) -> Unit,
    onNavigateToThread: (String) -> Unit,
    @Suppress("UNUSED_PARAMETER") onZapFeedback: (ZapFeedback) -> Unit,
+    onOpenLive: (String) -> Unit = {
+        com.vitorpamplona.amethyst.desktop.ui.live.LiveWatchController
+            .open(it)
+    },
    modifier: Modifier = Modifier,
 ) {
    val featured by state.featuredPack.collectAsState()
@@ -193,6 +198,15 @@ fun DiscoverScreen(
                }
            }

+            // ---- Live now (NIP-53) ----
+            Spacer(Modifier.height(24.dp))
+            LivesSection(
+                cache = cache,
+                relayManager = relayManager,
+                followSet = followedAuthors.authors,
+                onOpenLive = onOpenLive,
+            )
+
            // ---- Topic chips ----
            val chipTags = remember(current) { current?.let { state.hashtagsFor(it) } ?: emptyList() }
            if (chipTags.isNotEmpty()) {
@@ -73,6 +73,11 @@ object GlobalMediaPlayer {

    @Volatile private var audioPlayer: VideoPlayerState? = null

+    // In-flight `openUri` for the current video track. Cancelled before a new open so two rapid
+    // track switches (e.g. opening one live stream while another is still loading) can't interleave
+    // openUri calls on the single shared engine — that race left the player stuck / black.
+    @Volatile private var videoOpenJob: Job? = null
+
    private val initLock = Any()

    /**
@@ -120,12 +125,18 @@ object GlobalMediaPlayer {
                return
            }

-        if (current.url == url) {
+        // Reuse the engine only when it's already on this URL AND healthy. If the last attempt
+        // errored (a common transient for live HLS — a dead segment, a 403, a stream that just
+        // went live), fall through and re-open instead of leaving a stuck/errored surface.
+        if (current.url == url && current.errorReason == null) {
+            println("GlobalMediaPlayer.playVideo REUSE url=$url isPlaying=${current.isPlaying}")
            if (seekPosition > 0f) player.seekTo(seekPosition * 1000f)
            if (!current.isPlaying) player.play()
            return
        }

+        println("GlobalMediaPlayer.playVideo OPEN url=$url (was=${current.url} err=${current.errorReason})")
+
        // Reset engine volume to match the UI's default for the new track. The
        // kdroidFilter player retains `volume` across openUri calls, so a mute
        // on the prior track would otherwise carry over while the UI shows the
@@ -134,17 +145,20 @@ object GlobalMediaPlayer {

        _videoState.value = MediaPlaybackState(url = url, type = MediaType.VIDEO, isBuffering = true)

-        scope.launch(Dispatchers.IO) {
-            player.openUri(url)
-            // openUri auto-plays per InitialPlayerState.PLAY default. For an
-            // initial seek we wait for the first hasMedia=true emission then
-            // stop collecting (Flow.first terminates the collector cleanly,
-            // unlike `return@collect` which only exits the lambda).
-            if (seekPosition > 0f) {
-                snapshotFlow { player.hasMedia }.first { it }
-                player.seekTo(seekPosition * 1000f)
+        // Cancel any in-flight open so a rapid switch can't interleave openUri on the shared engine.
+        videoOpenJob?.cancel()
+        videoOpenJob =
+            scope.launch(Dispatchers.IO) {
+                player.openUri(url)
+                // openUri auto-plays per InitialPlayerState.PLAY default. For an
+                // initial seek we wait for the first hasMedia=true emission then
+                // stop collecting (Flow.first terminates the collector cleanly,
+                // unlike `return@collect` which only exits the lambda).
+                if (seekPosition > 0f) {
+                    snapshotFlow { player.hasMedia }.first { it }
+                    player.seekTo(seekPosition * 1000f)
+                }
            }
-        }
    }

    fun playAudio(url: String) {
@@ -236,6 +250,7 @@ object GlobalMediaPlayer {
    }

    fun stopVideo() {
+        videoOpenJob?.cancel()
        videoPlayer?.stop()
        _videoState.value = MediaPlaybackState()
        _isFullscreen.value = false
@@ -73,6 +73,44 @@ fun createFollowingFeedSubscription(
    )
 }

+/**
+ * Creates a subscription config for NIP-53 live streams (kind 30311). Pass [authors] to scope to a
+ * set of hosts (e.g. the user's follows); null fetches globally for discovery.
+ */
+fun createLiveActivitiesSubscription(
+    relays: Set<NormalizedRelayUrl>,
+    authors: List<String>? = null,
+    limit: Int = 100,
+    onEvent: (Event, Boolean, NormalizedRelayUrl, List<Filter>?) -> Unit,
+    onEose: (NormalizedRelayUrl, List<Filter>?) -> Unit = { _, _ -> },
+): SubscriptionConfig =
+    SubscriptionConfig(
+        subId = generateSubId("live-activities"),
+        filters = listOf(FilterBuilders.liveActivities(authors = authors, limit = limit)),
+        relays = relays,
+        onEvent = onEvent,
+        onEose = onEose,
+    )
+
+/**
+ * Creates a subscription config for the live chat (kind 1311) of a single stream, keyed by the
+ * stream's 30311 address (`kind:pubkey:d`).
+ */
+fun createLiveChatSubscription(
+    relays: Set<NormalizedRelayUrl>,
+    streamAddress: String,
+    limit: Int = 200,
+    onEvent: (Event, Boolean, NormalizedRelayUrl, List<Filter>?) -> Unit,
+    onEose: (NormalizedRelayUrl, List<Filter>?) -> Unit = { _, _ -> },
+): SubscriptionConfig =
+    SubscriptionConfig(
+        subId = generateSubId("live-chat-${streamAddress.take(24)}"),
+        filters = listOf(FilterBuilders.liveActivityChat(streamAddress, limit = limit)),
+        relays = relays,
+        onEvent = onEvent,
+        onEose = onEose,
+    )
+
 /**
 * Creates a subscription config for contact list (kind 3).
 */
@@ -21,6 +21,8 @@
 package com.vitorpamplona.amethyst.desktop.subscriptions

 import com.vitorpamplona.quartz.nip01Core.relay.filters.Filter
+import com.vitorpamplona.quartz.nip53LiveActivities.chat.LiveActivitiesChatMessageEvent
+import com.vitorpamplona.quartz.nip53LiveActivities.streaming.LiveActivitiesEvent
 import com.vitorpamplona.quartz.nip59Giftwrap.wraps.EphemeralGiftWrapEvent
 import com.vitorpamplona.quartz.nip59Giftwrap.wraps.GiftWrapEvent

@@ -31,6 +33,28 @@ import com.vitorpamplona.quartz.nip59Giftwrap.wraps.GiftWrapEvent
 object FilterBuilders {
    private val FEED_KINDS = listOf(1, 6, 16, 1068) // TextNoteEvent, RepostEvent, GenericRepostEvent, PollEvent

+    /** Filter for NIP-53 live streaming events (kind 30311), optionally scoped to specific hosts. */
+    fun liveActivities(
+        authors: List<String>? = null,
+        limit: Int = 100,
+    ): Filter =
+        Filter(
+            kinds = listOf(LiveActivitiesEvent.KIND),
+            authors = authors,
+            limit = limit,
+        )
+
+    /** Filter for NIP-53 live chat messages (kind 1311) tied to a stream by its root `a` tag. */
+    fun liveActivityChat(
+        streamAddress: String,
+        limit: Int = 200,
+    ): Filter =
+        Filter(
+            kinds = listOf(LiveActivitiesChatMessageEvent.KIND),
+            tags = mapOf("a" to listOf(streamAddress)),
+            limit = limit,
+        )
+
    /**
     * Creates a filter for text notes (kind 1) from all authors.
     *
@@ -28,6 +28,7 @@ import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip01Core.relay.client.reqs.SubscriptionListener
 import com.vitorpamplona.quartz.nip01Core.relay.filters.Filter
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import java.util.concurrent.atomic.AtomicLong

 /**
 * Represents an active relay subscription that can be unsubscribed.
@@ -122,4 +123,9 @@ fun rememberSubscription(
 /**
 * Generates a unique subscription ID with timestamp.
 */
-fun generateSubId(prefix: String): String = "$prefix-${System.currentTimeMillis()}"
+private val subIdCounter = AtomicLong(0)
+
+// Append a monotonic per-process counter so two subscriptions created in the same millisecond
+// (e.g. the live bar + the Discover Lives section on the same frame) can't collide on subId — a
+// collision would make one's unsubscribe tear down the other's REQ.
+fun generateSubId(prefix: String): String = "$prefix-${System.currentTimeMillis()}-${subIdCounter.incrementAndGet()}"
@@ -137,6 +137,7 @@ import com.vitorpamplona.amethyst.desktop.subscriptions.createSearchPeopleSubscr
 import com.vitorpamplona.amethyst.desktop.subscriptions.createThreadRepliesSubscription
 import com.vitorpamplona.amethyst.desktop.subscriptions.generateSubId
 import com.vitorpamplona.amethyst.desktop.subscriptions.rememberSubscription
+import com.vitorpamplona.amethyst.desktop.ui.live.LiveNowBar
 import com.vitorpamplona.amethyst.desktop.ui.media.LightboxOverlay
 import com.vitorpamplona.amethyst.desktop.ui.note.DesktopPollCard
 import com.vitorpamplona.amethyst.desktop.ui.note.NoteCard
@@ -580,6 +581,10 @@ fun FeedScreen(
    onZapFeedback: (ZapFeedback) -> Unit = {},
    onNavigateToRelays: () -> Unit = {},
    onSearchClick: () -> Unit = {},
+    onOpenLive: (String) -> Unit = {
+        com.vitorpamplona.amethyst.desktop.ui.live.LiveWatchController
+            .open(it)
+    },
 ) {
    val feedSearchActiveState = com.vitorpamplona.amethyst.desktop.ui.theme.LocalFeedSearchActive.current
    var searchActive by feedSearchActiveState
@@ -968,6 +973,20 @@ fun FeedScreen(
            // Reserve space for the header card that floats above the feed.
            Spacer(Modifier.height(headerSpacerHeight))

+            // Pinned "live now" bar, scoped to this column's audience (Following / Global only).
+            if (feedMode == FeedMode.FOLLOWING || feedMode == FeedMode.GLOBAL) {
+                val liveBarPadding = LocalReadingSidePadding.current
+                Spacer(Modifier.height(8.dp))
+                LiveNowBar(
+                    cache = localCache,
+                    relayManager = relayManager,
+                    scopeAuthors = if (feedMode == FeedMode.FOLLOWING) followedUsers else null,
+                    onOpenLive = onOpenLive,
+                    modifier = Modifier.padding(horizontal = liveBarPadding + 12.dp),
+                )
+                Spacer(Modifier.height(4.dp))
+            }
+
            // Feed content based on FeedState
            when (val state = feedState) {
                is FeedState.Loading -> {
@@ -0,0 +1,144 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.desktop.ui.live
+
+import com.vitorpamplona.amethyst.commons.model.nip53LiveActivities.LiveActivitiesChannel
+import com.vitorpamplona.amethyst.commons.nip53LiveActivities.LiveActivitySorting
+import com.vitorpamplona.amethyst.commons.nip53LiveActivities.LiveActivitySorting.LiveActivityRank
+import com.vitorpamplona.quartz.nip01Core.tags.hashtags.HashtagTag
+import com.vitorpamplona.quartz.nip53LiveActivities.streaming.tags.StatusTag
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+/**
+ * Ranks + filters cached NIP-53 live-stream channels for the Desktop Discover grid and the
+ * per-column live bar, delegating the ordering contract to the shared, unit-tested
+ * [LiveActivitySorting] (so Desktop and Android order streams identically).
+ *
+ * [isOfflineNow] lets the caller feed in the online-probe verdict for a stream's `.m3u8` so a dead
+ * `status=live` sinks; pass `{ false }` until the probe is wired in.
+ */
+object LiveActivityRanking {
+    fun rankOf(
+        channel: LiveActivitiesChannel,
+        followSet: Set<String>,
+        isOfflineNow: Boolean,
+    ): LiveActivityRank {
+        val info = channel.info
+        if (info == null) {
+            return LiveActivityRank(LiveActivitySorting.ORDER_ENDED, 0, 0, 0L, channel.address.toValue())
+        }
+        val participants = info.participants()
+        val involved =
+            buildSet {
+                add(info.pubKey)
+                participants.forEach { add(it.pubKey) }
+            }
+        val followParticipants = involved.count { it in followSet }
+        val startOrCreated = info.starts() ?: info.createdAt
+        return LiveActivityRank(
+            statusOrder = LiveActivitySorting.statusOrder(info.status(), isOfflineNow),
+            followParticipants = followParticipants,
+            totalParticipants = participants.size,
+            startOrCreated = startOrCreated,
+            idHex = channel.address.toValue(),
+        )
+    }
+
+    /** Best-first ranked list for the Discover grid (live > planned > ended). */
+    fun rankForDiscover(
+        channels: Collection<LiveActivitiesChannel>,
+        followSet: Set<String>,
+        isOfflineNow: (LiveActivitiesChannel) -> Boolean = { false },
+    ): List<LiveActivitiesChannel> = LiveActivitySorting.sortDescending(channels) { rankOf(it, followSet, isOfflineNow(it)) }
+
+    /**
+     * The set of channels currently live-and-fresh within [followSet] (or globally when [followSet]
+     * is null), for the per-column "live now" bar. Ranked by viewer count (`current_participants`)
+     * per the design decision, newest first as a tiebreak.
+     */
+    fun liveNowForBar(
+        channels: Collection<LiveActivitiesChannel>,
+        followSet: Set<String>?,
+        now: Long = TimeUtils.now(),
+        isOfflineNow: (LiveActivitiesChannel) -> Boolean = { false },
+    ): List<LiveActivitiesChannel> {
+        val eligible =
+            channels.filter { channel ->
+                val info = channel.info ?: return@filter false
+                val fresh = LiveActivitySorting.isLiveAndFresh(info.status(), info.createdAt, now, isOfflineNow(channel))
+                fresh && (followSet == null || involvesFollow(channel, followSet))
+            }
+        // Rank by viewers (current_participants), then recency. MUST go through sortDescending so the
+        // keys are snapshotted once — channel.info is a var swapped from relay threads, and reading it
+        // lazily inside a comparator violates TimSort's contract and crashes the feed column.
+        return LiveActivitySorting.sortDescending(eligible) { channel ->
+            val info = channel.info
+            LiveActivityRank(
+                statusOrder = LiveActivitySorting.ORDER_LIVE,
+                followParticipants = 0,
+                totalParticipants = info?.currentParticipants() ?: 0,
+                startOrCreated = info?.createdAt ?: 0L,
+                idHex = channel.address.toValue(),
+            )
+        }
+    }
+
+    private fun involvesFollow(
+        channel: LiveActivitiesChannel,
+        followSet: Set<String>,
+    ): Boolean {
+        val info = channel.info ?: return false
+        if (info.pubKey in followSet) return true
+        return info.participants().any { it.pubKey in followSet }
+    }
+
+    /** Client-side search over cached streams: title, host name, and hashtags. */
+    fun matchesQuery(
+        channel: LiveActivitiesChannel,
+        query: String,
+    ): Boolean {
+        if (query.isBlank()) return true
+        val q = query.trim()
+        val info = channel.info ?: return false
+        if (info.title()?.contains(q, ignoreCase = true) == true) return true
+        if (channel.creatorName()?.contains(q, ignoreCase = true) == true) return true
+        if (info.summary()?.contains(q, ignoreCase = true) == true) return true
+        return info.tags.any { tag -> HashtagTag.parse(tag)?.contains(q, ignoreCase = true) == true }
+    }
+
+    fun isLive(channel: LiveActivitiesChannel): Boolean = channel.info?.status() == StatusTag.STATUS.LIVE
+
+    fun isPlanned(channel: LiveActivitiesChannel): Boolean = channel.info?.status() == StatusTag.STATUS.PLANNED
+
+    /**
+     * True only when the stream is genuinely live right now: `status=live` AND its 30311 is fresh
+     * (re-published within the freshness window). Used to keep the "LIVE NOW" surfaces free of
+     * ended/planned/zombie streams.
+     */
+    fun isLiveNow(
+        channel: LiveActivitiesChannel,
+        now: Long = TimeUtils.now(),
+        isOfflineNow: Boolean = false,
+    ): Boolean {
+        val info = channel.info ?: return false
+        return LiveActivitySorting.isLiveAndFresh(info.status(), info.createdAt, now, isOfflineNow)
+    }
+}
@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.desktop.ui.live
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import com.vitorpamplona.amethyst.desktop.cache.DesktopLocalCache
+import com.vitorpamplona.amethyst.desktop.network.RelayConnectionManager
+import com.vitorpamplona.amethyst.desktop.subscriptions.createLiveActivitiesSubscription
+import com.vitorpamplona.amethyst.desktop.subscriptions.rememberSubscription
+
+/**
+ * Compact pinned "live now" bar for the top of a feed column. Shows the single most-watched live
+ * host in the column's audience ([scopeAuthors] = the column's follows, or null for the global
+ * feed) plus a "+N live ›" affordance that expands the rest. Hidden entirely when nobody in scope
+ * is live. Clicking a host opens the watch screen via [onOpenLive].
+ */
+@Composable
+fun LiveNowBar(
+    cache: DesktopLocalCache,
+    relayManager: RelayConnectionManager,
+    scopeAuthors: Set<String>?,
+    onOpenLive: (String) -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val connectedRelays by relayManager.connectedRelays.collectAsState()
+
+    // Keyed on the Set (stable identity from the account state holder) — not a fresh list per
+    // recomposition — so the subscription and the snapshot below don't churn on unrelated recomposes.
+    rememberSubscription(connectedRelays, scopeAuthors, relayManager = relayManager) {
+        if (connectedRelays.isEmpty()) {
+            null
+        } else {
+            createLiveActivitiesSubscription(
+                relays = connectedRelays,
+                authors = scopeAuthors?.toList(),
+                onEvent = { event, _, relay, _ -> cache.consume(event, relay) },
+            )
+        }
+    }
+
+    val version by cache.liveActivityVersion.collectAsState()
+    val liveNow =
+        remember(version, scopeAuthors) {
+            LiveActivityRanking.liveNowForBar(cache.snapshotLiveActivities(), scopeAuthors)
+        }
+
+    if (liveNow.isEmpty()) return
+
+    val top = liveNow.first()
+    var expanded by remember { mutableStateOf(false) }
+
+    Row(
+        verticalAlignment = Alignment.CenterVertically,
+        modifier =
+            modifier
+                .fillMaxWidth()
+                .clip(RoundedCornerShape(10.dp))
+                .background(MaterialTheme.colorScheme.surfaceVariant)
+                .clickable { onOpenLive(top.address.toValue()) }
+                .padding(horizontal = 14.dp, vertical = 10.dp),
+    ) {
+        LiveDotSmall()
+        Spacer(Modifier.width(8.dp))
+        Text(
+            text = topLabel(top.toBestDisplayName()),
+            style = MaterialTheme.typography.bodyMedium,
+            fontWeight = FontWeight.SemiBold,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+            modifier = Modifier.weight(1f),
+        )
+        if (liveNow.size > 1) {
+            Spacer(Modifier.width(8.dp))
+            Box {
+                Text(
+                    text = "+${liveNow.size - 1} live ›",
+                    style = MaterialTheme.typography.labelMedium,
+                    color = MaterialTheme.colorScheme.primary,
+                    fontWeight = FontWeight.SemiBold,
+                    modifier = Modifier.clickable { expanded = true },
+                )
+                DropdownMenu(expanded = expanded, onDismissRequest = { expanded = false }) {
+                    liveNow.forEach { channel ->
+                        DropdownMenuItem(
+                            text = { Text(channel.toBestDisplayName(), maxLines = 1, overflow = TextOverflow.Ellipsis) },
+                            onClick = {
+                                expanded = false
+                                onOpenLive(channel.address.toValue())
+                            },
+                        )
+                    }
+                }
+            }
+        }
+    }
+}
+
+private fun topLabel(name: String): String = "$name is live"
+
+@Composable
+private fun LiveDotSmall() {
+    Box(
+        modifier =
+            Modifier
+                .size(9.dp)
+                .clip(CircleShape)
+                .background(Color(0xFFD32F2F)),
+    )
+}
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.desktop.ui.live
+
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+/**
+ * App-level controller for the full-window live watch screen. Holds the address (`kind:pubkey:d`)
+ * of the stream currently being watched, or null when the watch overlay is closed.
+ *
+ * This is a singleton (like [com.vitorpamplona.amethyst.desktop.service.media.GlobalMediaPlayer])
+ * so any live surface — the Discover grid card, the per-column live bar, a profile Streams tab —
+ * can open the watch overlay via [open] without threading a callback up through the whole deck /
+ * single-pane navigation tree. The overlay itself is rendered once at the composition root in
+ * `Main.kt`, observing [current].
+ */
+object LiveWatchController {
+    private val _current = MutableStateFlow<String?>(null)
+    val current: StateFlow<String?> = _current.asStateFlow()
+
+    fun open(streamAddress: String) {
+        _current.value = streamAddress
+    }
+
+    fun close() {
+        _current.value = null
+    }
+}
@@ -0,0 +1,373 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.desktop.ui.live
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.aspectRatio
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.VerticalDivider
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import com.vitorpamplona.amethyst.commons.icons.symbols.MaterialSymbols
+import com.vitorpamplona.amethyst.desktop.account.AccountState
+import com.vitorpamplona.amethyst.desktop.cache.DesktopLocalCache
+import com.vitorpamplona.amethyst.desktop.network.DesktopRelayConnectionManager
+import com.vitorpamplona.amethyst.desktop.service.media.GlobalMediaPlayer
+import com.vitorpamplona.amethyst.desktop.subscriptions.createLiveChatSubscription
+import com.vitorpamplona.amethyst.desktop.subscriptions.rememberSubscription
+import com.vitorpamplona.amethyst.desktop.ui.media.DesktopVideoPlayer
+import com.vitorpamplona.quartz.nip01Core.core.Address
+import com.vitorpamplona.quartz.nip53LiveActivities.chat.LiveActivitiesChatMessageEvent
+import com.vitorpamplona.quartz.nip53LiveActivities.streaming.tags.StatusTag
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import com.vitorpamplona.amethyst.commons.icons.symbols.Icon as SymbolIcon
+
+/**
+ * Full-window watch screen for a NIP-53 live stream: HLS player on the left, live chat (kind 1311)
+ * on the right, host/metadata + status below the player. Rendered as an app-root overlay driven by
+ * [LiveWatchController]; [onClose] tears it down and returns to the deck / single-pane view.
+ *
+ * v1 scope: watch + read + post chat. Zap-the-stream and the live-vs-VOD player refinements
+ * (seek-bar suppression, stall watchdog) are follow-ups.
+ */
+@Composable
+fun LiveWatchScreen(
+    address: String,
+    cache: DesktopLocalCache,
+    relayManager: DesktopRelayConnectionManager,
+    account: AccountState.LoggedIn?,
+    onClose: () -> Unit,
+) {
+    val channel =
+        remember(address) {
+            Address.parse(address)?.let { cache.getOrCreateLiveActivityChannel(it) }
+        }
+
+    LaunchedEffect(address, channel?.info) {
+        val info = channel?.info
+        println(
+            "LiveWatchScreen open address=$address status=${info?.status()} " +
+                "streaming=${info?.streaming() ?: "<none>"} recording=${info?.recording() ?: "<none>"}",
+        )
+    }
+
+    // Stop playback when the watch overlay closes (leaves composition) so audio/decoding doesn't
+    // keep running in the background. Switching to another stream keeps the overlay composed (only
+    // `address` changes), so this fires only on a real close.
+    DisposableEffect(Unit) {
+        onDispose { GlobalMediaPlayer.stopVideo() }
+    }
+
+    Surface(color = MaterialTheme.colorScheme.background, modifier = Modifier.fillMaxSize()) {
+        if (channel == null) {
+            WatchError("This stream could not be opened.", onClose)
+            return@Surface
+        }
+
+        val connectedRelays by relayManager.connectedRelays.collectAsState()
+
+        // Live chat subscription for this stream (kind 1311 by the root `a` tag), torn down on close.
+        rememberSubscription(connectedRelays, address, relayManager = relayManager) {
+            if (connectedRelays.isEmpty()) {
+                null
+            } else {
+                createLiveChatSubscription(
+                    relays = connectedRelays,
+                    streamAddress = address,
+                    onEvent = { event, _, relay, _ -> cache.consume(event, relay) },
+                )
+            }
+        }
+
+        Column(modifier = Modifier.fillMaxSize()) {
+            // Top bar
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                modifier = Modifier.fillMaxWidth().padding(start = 4.dp, end = 12.dp, top = 16.dp, bottom = 8.dp),
+            ) {
+                IconButton(onClick = onClose) {
+                    SymbolIcon(symbol = MaterialSymbols.Close, contentDescription = "Close")
+                }
+                Spacer(Modifier.width(4.dp))
+                Text(
+                    text = channel.toBestDisplayName(),
+                    style = MaterialTheme.typography.titleMedium,
+                    fontWeight = FontWeight.SemiBold,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                )
+            }
+            HorizontalDivider()
+
+            Row(modifier = Modifier.fillMaxSize()) {
+                // Left: player + metadata
+                Column(modifier = Modifier.weight(1f).fillMaxSize().padding(16.dp)) {
+                    val streamUrl = channel.info?.streaming()
+                    if (streamUrl != null) {
+                        DesktopVideoPlayer(
+                            url = streamUrl,
+                            autoPlay = true,
+                            isLive = channel.info?.status() == StatusTag.STATUS.LIVE,
+                            modifier = Modifier.fillMaxWidth().aspectRatio(16f / 9f).clip(RoundedCornerShape(8.dp)),
+                        )
+                    } else {
+                        Box(
+                            modifier =
+                                Modifier
+                                    .fillMaxWidth()
+                                    .aspectRatio(16f / 9f)
+                                    .clip(RoundedCornerShape(8.dp))
+                                    .background(MaterialTheme.colorScheme.surfaceVariant),
+                            contentAlignment = Alignment.Center,
+                        ) {
+                            Text("Stream is offline", color = MaterialTheme.colorScheme.onSurfaceVariant)
+                        }
+                    }
+
+                    Spacer(Modifier.height(12.dp))
+                    WatchHeader(channel = channel)
+                }
+
+                VerticalDivider()
+
+                // Right: live chat
+                Column(modifier = Modifier.width(380.dp).fillMaxSize()) {
+                    Text(
+                        text = "LIVE CHAT",
+                        style = MaterialTheme.typography.labelMedium,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        modifier = Modifier.padding(12.dp),
+                    )
+                    HorizontalDivider()
+                    ChatColumn(
+                        channel = channel,
+                        account = account,
+                        relayManager = relayManager,
+                        modifier = Modifier.weight(1f).fillMaxWidth(),
+                    )
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun WatchHeader(channel: com.vitorpamplona.amethyst.commons.model.nip53LiveActivities.LiveActivitiesChannel) {
+    val info = channel.info
+    Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.fillMaxWidth()) {
+        if (info?.status() == StatusTag.STATUS.LIVE) {
+            Box(modifier = Modifier.size(10.dp).clip(CircleShape).background(Color(0xFFD32F2F)))
+            Spacer(Modifier.width(6.dp))
+            Text("LIVE", style = MaterialTheme.typography.labelMedium, color = Color(0xFFD32F2F), fontWeight = FontWeight.Bold)
+            Spacer(Modifier.width(12.dp))
+        }
+        val host = channel.creatorName()
+        if (host != null) {
+            Text(
+                text = host,
+                style = MaterialTheme.typography.bodyMedium,
+                fontWeight = FontWeight.SemiBold,
+            )
+        }
+        Spacer(Modifier.weight(1f))
+        val viewers = info?.currentParticipants()
+        if (viewers != null) {
+            Text("$viewers watching", style = MaterialTheme.typography.labelMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+        }
+    }
+    val summary = channel.summary()
+    if (!summary.isNullOrBlank()) {
+        Spacer(Modifier.height(6.dp))
+        Text(summary, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 3, overflow = TextOverflow.Ellipsis)
+    }
+}
+
+@Composable
+private fun ChatColumn(
+    channel: com.vitorpamplona.amethyst.commons.model.nip53LiveActivities.LiveActivitiesChannel,
+    account: AccountState.LoggedIn?,
+    relayManager: DesktopRelayConnectionManager,
+    modifier: Modifier = Modifier,
+) {
+    val notesState by channel
+        .flow()
+        .notes.stateFlow
+        .collectAsState()
+    // Newest first so reverseLayout puts the latest message at the visual bottom.
+    val messages =
+        remember(notesState) {
+            channel.notes
+                .values()
+                .filter { it.event is LiveActivitiesChatMessageEvent }
+                .sortedByDescending { it.createdAt() ?: 0L }
+        }
+
+    val listState = rememberLazyListState()
+    // Auto-stick to the newest message while the user is at the bottom (index 0 in reverseLayout).
+    // Keyed on the newest message id (not size) so it still fires once the 500-cap prune keeps size
+    // flat (drop-one/add-one) on a busy stream.
+    LaunchedEffect(messages.firstOrNull()?.idHex) {
+        if (messages.isNotEmpty() && listState.firstVisibleItemIndex <= 1) {
+            listState.animateScrollToItem(0)
+        }
+    }
+
+    Column(modifier = modifier) {
+        LazyColumn(
+            state = listState,
+            reverseLayout = true,
+            verticalArrangement = Arrangement.spacedBy(6.dp),
+            modifier = Modifier.weight(1f).fillMaxWidth().padding(horizontal = 12.dp, vertical = 8.dp),
+        ) {
+            items(messages, key = { it.idHex }) { note ->
+                ChatMessageRow(
+                    author = note.author?.toBestDisplayName() ?: "anon",
+                    content = note.event?.content.orEmpty(),
+                )
+            }
+        }
+        HorizontalDivider()
+        ChatComposer(channel = channel, account = account, relayManager = relayManager)
+    }
+}
+
+@Composable
+private fun ChatMessageRow(
+    author: String,
+    content: String,
+) {
+    Column(modifier = Modifier.fillMaxWidth()) {
+        Text(
+            text = author,
+            style = MaterialTheme.typography.labelMedium,
+            fontWeight = FontWeight.SemiBold,
+            color = MaterialTheme.colorScheme.primary,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+        )
+        Text(text = content, style = MaterialTheme.typography.bodyMedium)
+    }
+}
+
+@Composable
+private fun ChatComposer(
+    channel: com.vitorpamplona.amethyst.commons.model.nip53LiveActivities.LiveActivitiesChannel,
+    account: AccountState.LoggedIn?,
+    relayManager: DesktopRelayConnectionManager,
+) {
+    val scope = rememberCoroutineScope()
+    var text by remember { mutableStateOf("") }
+    var sending by remember { mutableStateOf(false) }
+
+    val canPost = account != null && !account.isReadOnly
+
+    Row(
+        verticalAlignment = Alignment.CenterVertically,
+        modifier = Modifier.fillMaxWidth().padding(8.dp),
+    ) {
+        OutlinedTextField(
+            value = text,
+            onValueChange = { text = it },
+            enabled = canPost && !sending,
+            singleLine = true,
+            placeholder = { Text(if (canPost) "Say something…" else "Log in to chat") },
+            modifier = Modifier.weight(1f),
+        )
+        Spacer(Modifier.width(8.dp))
+        TextButton(
+            enabled = canPost && !sending && text.isNotBlank(),
+            onClick = {
+                val acct = account ?: return@TextButton
+                val body = text.trim()
+                if (body.isBlank()) return@TextButton
+                sending = true
+                scope.launch {
+                    try {
+                        withContext(Dispatchers.IO) {
+                            val template = LiveActivitiesChatMessageEvent.message(body, channel.toATag())
+                            val signed = acct.signer.sign(template)
+                            relayManager.publish(signed, relayManager.connectedRelays.value)
+                        }
+                        text = ""
+                    } finally {
+                        sending = false
+                    }
+                }
+            },
+        ) {
+            Text("Send")
+        }
+    }
+}
+
+@Composable
+private fun WatchError(
+    message: String,
+    onClose: () -> Unit,
+) {
+    Column(
+        horizontalAlignment = Alignment.CenterHorizontally,
+        verticalArrangement = Arrangement.Center,
+        modifier = Modifier.fillMaxSize(),
+    ) {
+        Text(message, style = MaterialTheme.typography.bodyLarge)
+        Spacer(Modifier.height(12.dp))
+        TextButton(onClick = onClose) { Text("Close") }
+    }
+}
@@ -0,0 +1,292 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.desktop.ui.live
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ExperimentalLayoutApi
+import androidx.compose.foundation.layout.FlowRow
+import androidx.compose.foundation.layout.FlowRowOverflow
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.aspectRatio
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.Card
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import coil3.compose.AsyncImage
+import com.vitorpamplona.amethyst.commons.model.nip53LiveActivities.LiveActivitiesChannel
+import com.vitorpamplona.amethyst.desktop.cache.DesktopLocalCache
+import com.vitorpamplona.amethyst.desktop.network.RelayConnectionManager
+import com.vitorpamplona.amethyst.desktop.subscriptions.createLiveActivitiesSubscription
+import com.vitorpamplona.amethyst.desktop.subscriptions.rememberSubscription
+import com.vitorpamplona.quartz.nip53LiveActivities.streaming.tags.StatusTag
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+/**
+ * "LIVE NOW" section for the Desktop Discover screen: subscribes to NIP-53 live streams (kind
+ * 30311) while visible, ranks them via the shared [LiveActivityRanking] (live > planned > ended,
+ * follow-participation, then viewers), and offers a client-side search over title / host / hashtag.
+ * Clicking a card invokes [onOpenLive] with the stream's address (`kind:pubkey:d`).
+ */
+@OptIn(ExperimentalLayoutApi::class)
+@Composable
+fun LivesSection(
+    cache: DesktopLocalCache,
+    relayManager: RelayConnectionManager,
+    followSet: Set<String>,
+    onOpenLive: (String) -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val connectedRelays by relayManager.connectedRelays.collectAsState()
+
+    // Subscribe to global live streams while this section is composed; torn down on dispose.
+    rememberSubscription(connectedRelays, relayManager = relayManager) {
+        if (connectedRelays.isEmpty()) {
+            null
+        } else {
+            createLiveActivitiesSubscription(
+                relays = connectedRelays,
+                authors = null,
+                onEvent = { event, _, relay, _ -> cache.consume(event, relay) },
+            )
+        }
+    }
+
+    val version by cache.liveActivityVersion.collectAsState()
+    var query by rememberSaveable { mutableStateOf("") }
+
+    // "LIVE NOW" shows only streams that are genuinely live right now — never planned or ended.
+    val ranked =
+        remember(version, query, followSet) {
+            val liveOnly = cache.snapshotLiveActivities().filter { LiveActivityRanking.isLiveNow(it) }
+            LiveActivityRanking
+                .rankForDiscover(liveOnly, followSet)
+                .filter { LiveActivityRanking.matchesQuery(it, query) }
+        }
+
+    // Hide the whole section when nothing is live (keeps Discover clean; no empty band).
+    if (ranked.isEmpty() && query.isBlank()) return
+
+    Column(modifier = modifier.fillMaxWidth()) {
+        Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.fillMaxWidth()) {
+            LiveDot()
+            Spacer(Modifier.width(6.dp))
+            Text(
+                text = "LIVE NOW",
+                style = MaterialTheme.typography.titleMedium,
+                fontWeight = FontWeight.SemiBold,
+                modifier = Modifier.weight(1f),
+            )
+        }
+        Spacer(Modifier.height(8.dp))
+        OutlinedTextField(
+            value = query,
+            onValueChange = { query = it },
+            singleLine = true,
+            placeholder = { Text("Search live streams…") },
+            keyboardOptions = KeyboardOptions.Default,
+            modifier = Modifier.fillMaxWidth(),
+        )
+        Spacer(Modifier.height(12.dp))
+        if (ranked.isEmpty()) {
+            Text(
+                text = "No live streams match \"$query\".",
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        } else {
+            // Cap at two rows so the rest of Discover ("From the pack" etc.) stays visible; extra
+            // live streams are still reachable via the search box and the per-column live bar.
+            FlowRow(
+                horizontalArrangement = Arrangement.spacedBy(12.dp),
+                verticalArrangement = Arrangement.spacedBy(12.dp),
+                maxLines = 2,
+                overflow = FlowRowOverflow.Clip,
+                modifier = Modifier.fillMaxWidth(),
+            ) {
+                ranked.forEach { channel ->
+                    LiveStreamCard(
+                        channel = channel,
+                        onClick = { onOpenLive(channel.address.toValue()) },
+                    )
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun LiveStreamCard(
+    channel: LiveActivitiesChannel,
+    onClick: () -> Unit,
+) {
+    val info = channel.info
+    Card(
+        modifier =
+            Modifier
+                .width(240.dp)
+                .clickable(onClick = onClick),
+        colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceVariant),
+        shape = RoundedCornerShape(12.dp),
+    ) {
+        Box {
+            val image = channel.profilePicture()
+            if (image != null) {
+                AsyncImage(
+                    model = image,
+                    contentDescription = null,
+                    modifier =
+                        Modifier
+                            .fillMaxWidth()
+                            .aspectRatio(16f / 9f)
+                            .clip(RoundedCornerShape(topStart = 12.dp, topEnd = 12.dp)),
+                )
+            } else {
+                Box(
+                    modifier =
+                        Modifier
+                            .fillMaxWidth()
+                            .aspectRatio(16f / 9f)
+                            .background(MaterialTheme.colorScheme.surface),
+                )
+            }
+            StatusBadge(
+                channel = channel,
+                modifier = Modifier.align(Alignment.TopStart).padding(6.dp),
+            )
+        }
+        Column(modifier = Modifier.padding(10.dp)) {
+            Text(
+                text = channel.toBestDisplayName(),
+                style = MaterialTheme.typography.bodyMedium,
+                fontWeight = FontWeight.SemiBold,
+                maxLines = 2,
+                overflow = TextOverflow.Ellipsis,
+            )
+            val host = channel.creatorName()
+            if (host != null) {
+                Spacer(Modifier.height(2.dp))
+                Text(
+                    text = host,
+                    style = MaterialTheme.typography.labelMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                )
+            }
+            val viewers = info?.currentParticipants()
+            if (viewers != null && LiveActivityRanking.isLive(channel)) {
+                Spacer(Modifier.height(2.dp))
+                Text(
+                    text = "$viewers watching",
+                    style = MaterialTheme.typography.labelSmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun StatusBadge(
+    channel: LiveActivitiesChannel,
+    modifier: Modifier = Modifier,
+) {
+    val status = channel.info?.status()
+    when (status) {
+        StatusTag.STATUS.LIVE ->
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                modifier =
+                    modifier
+                        .clip(RoundedCornerShape(4.dp))
+                        .background(Color(0xE6D32F2F))
+                        .padding(horizontal = 6.dp, vertical = 2.dp),
+            ) {
+                Text("LIVE", style = MaterialTheme.typography.labelSmall, color = Color.White, fontWeight = FontWeight.Bold)
+            }
+
+        StatusTag.STATUS.PLANNED ->
+            Text(
+                text = startsInLabel(channel.info?.starts()),
+                style = MaterialTheme.typography.labelSmall,
+                color = Color.White,
+                modifier =
+                    modifier
+                        .clip(RoundedCornerShape(4.dp))
+                        .background(Color(0xCC000000))
+                        .padding(horizontal = 6.dp, vertical = 2.dp),
+            )
+
+        else -> Unit
+    }
+}
+
+@Composable
+private fun LiveDot() {
+    Box(
+        modifier =
+            Modifier
+                .size(10.dp)
+                .clip(CircleShape)
+                .background(Color(0xFFD32F2F)),
+    )
+}
+
+private fun startsInLabel(startsAt: Long?): String {
+    if (startsAt == null) return "SCHEDULED"
+    val delta = startsAt - TimeUtils.now()
+    if (delta <= 0) return "SCHEDULED"
+    val hours = delta / 3600
+    val minutes = (delta % 3600) / 60
+    return when {
+        hours >= 24 -> "in ${hours / 24}d"
+        hours >= 1 -> "in ${hours}h"
+        else -> "in ${minutes}m"
+    }
+}
@@ -63,6 +63,7 @@ fun DesktopVideoPlayer(
    viewMode: ViewMode = ViewMode.DEFAULT,
    onViewModeChange: ((ViewMode) -> Unit)? = null,
    trailingControls: @Composable (() -> Unit)? = null,
+    isLive: Boolean = false,
 ) {
    val videoState by GlobalMediaPlayer.videoState.collectAsState()
    val isActiveVideo = videoState.url == url
@@ -89,6 +90,14 @@ fun DesktopVideoPlayer(
        }
    }

+    // Surface playback errors to the log — kdroidFilter reports these only via state, so without
+    // this a stream that fails to start ("live doesn't start") leaves no trace.
+    LaunchedEffect(isActiveVideo, videoState.errorReason) {
+        if (isActiveVideo && videoState.errorReason != null) {
+            println("DesktopVideoPlayer ERROR url=$url reason=${videoState.errorReason}")
+        }
+    }
+
    if (isActiveVideo && videoState.aspectRatio != 16f / 9f) {
        aspectRatio = videoState.aspectRatio
    }
@@ -167,6 +176,7 @@ fun DesktopVideoPlayer(
                    },
                onViewModeChange = onViewModeChange,
                trailingControls = trailingControls,
+                isLive = isLive,
            )
        }
    }
@@ -34,6 +34,7 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -72,6 +73,7 @@ fun VideoControls(
    viewMode: ViewMode = ViewMode.DEFAULT,
    onViewModeChange: ((ViewMode) -> Unit)? = null,
    trailingControls: @Composable (() -> Unit)? = null,
+    isLive: Boolean = false,
 ) {
    var hovering by remember { mutableStateOf(false) }

@@ -128,18 +130,21 @@ fun VideoControls(
                        .background(Color.Black.copy(alpha = 0.6f))
                        .padding(horizontal = 8.dp),
            ) {
-                // Seek slider (full width, no horizontal competition)
-                Slider(
-                    value = position,
-                    onValueChange = onSeek,
-                    modifier = Modifier.fillMaxWidth(),
-                    colors =
-                        SliderDefaults.colors(
-                            thumbColor = Color.White,
-                            activeTrackColor = MaterialTheme.colorScheme.primary,
-                            inactiveTrackColor = Color.White.copy(alpha = 0.3f),
-                        ),
-                )
+                // Seek slider (full width, no horizontal competition). Hidden for live streams —
+                // the underlying HLS is non-seekable, so a scrubber would be inert and misleading.
+                if (!isLive) {
+                    Slider(
+                        value = position,
+                        onValueChange = onSeek,
+                        modifier = Modifier.fillMaxWidth(),
+                        colors =
+                            SliderDefaults.colors(
+                                thumbColor = Color.White,
+                                activeTrackColor = MaterialTheme.colorScheme.primary,
+                                inactiveTrackColor = Color.White.copy(alpha = 0.3f),
+                            ),
+                    )
+                }

                // Buttons row
                Row(
@@ -159,11 +164,32 @@ fun VideoControls(
                        )
                    }

-                    Text(
-                        text = "${formatTime(currentTime)} / ${formatTime(duration)}",
-                        style = MaterialTheme.typography.labelSmall,
-                        color = Color.White,
-                    )
+                    if (isLive) {
+                        // Live: a single "elapsed since you started watching" timer + a LIVE dot —
+                        // no total duration (the stream has no fixed end).
+                        Box(
+                            modifier =
+                                Modifier
+                                    .size(8.dp)
+                                    .background(Color(0xFFD32F2F), shape = CircleShape),
+                        )
+                        Text(
+                            text = "LIVE",
+                            style = MaterialTheme.typography.labelSmall,
+                            color = Color(0xFFFF5252),
+                        )
+                        Text(
+                            text = formatTime(currentTime),
+                            style = MaterialTheme.typography.labelSmall,
+                            color = Color.White,
+                        )
+                    } else {
+                        Text(
+                            text = "${formatTime(currentTime)} / ${formatTime(duration)}",
+                            style = MaterialTheme.typography.labelSmall,
+                            color = Color.White,
+                        )
+                    }

                    // Spacer pushes right-side controls to the end
                    Box(Modifier.weight(1f))
@@ -0,0 +1,467 @@
+---
+title: Desktop Live Media (NIP-53) — Consume & Discover
+type: feat
+status: active
+date: 2026-08-20
+origin: docs/brainstorms/2026-08-20-feat-desktop-live-media-brainstorm.md
+---
+
+# ✨ Desktop Live Media (NIP-53) — Consume & Discover
+
+## Enhancement Summary
+
+**Deepened on:** 2026-08-20 (7 parallel research/review agents: performance, architecture,
+simplicity, flow/edge-cases, security, HLS+chat best-practices, in-repo Compose patterns.)
+
+### Key improvements folded in
+1. **Player reality check (kdroidFilter 0.11.4):** no `isLive` flag, no buffered ranges, no
+   stall detector (except Linux). `duration == 0.0` is the live signal **but is ambiguous with
+   loading** → detect live/VOD from the **NIP-53 `status` tag** (+ manifest `#EXT-X-ENDLIST`
+   for precise ended), and **build our own stall/reconnect watchdog**. `seekTo` is a hard no-op
+   at `duration<=0`, so suppressing the seek bar for live is confirmed safe.
+2. **Chat = one coalescing pipeline**, reusing the existing 250ms `BasicBundledInsert` feed path
+   (do **not** hand-roll a chat list). Ingest→dedup-by-id→moderate→classify→batch→ring-trim(500)
+   →immutable-commit→`LazyColumn(reverseLayout,key=id)`→auto-scroll(`derivedStateOf`+`yield`).
+3. **Three factual corrections** to the original plan (see ⚠️ callouts): `OnlineChecker` is
+   Android-only (must extract + swap `android.util.LruCache`); `DesktopLocalCache` has **no channel
+   abstraction** (must stand up the first one); the watch-screen host I assumed (window-level
+   overlay) **doesn't exist** — `DesktopScreen`/`navState` are per-column.
+4. **Security:** URL-scheme allowlist gating both the player **and** the "Open in default player"
+   fallback; probe-on-intent (not on discovery) via the proxy-aware client; verify participant
+   `proof`; sanitize chat (bidi/auto-load).
+5. **Performance:** the player singleton has a **real unsynchronized race** + 60/s position-tick
+   recompose churn; Desktop has **no pruning** today (must add the trigger); snapshot **all**
+   comparator keys (incl. volatile `current_participants`) to avoid TimSort violations.
+6. **Scope correction:** the standalone "Lives" sidebar destination is **removed** — it
+   contradicted the brainstorm decision to *fold lives into Discover*.
+
+### New considerations discovered
+- Mid-watch lifecycle (live→ended, URL rotation, stall) is the highest-risk cluster and is now
+  first-class in Phase 0/3.
+- Mute/block enforcement in live chat is a **known silent-no-op gap** on Desktop (memory
+  `desktop_moderation_safety.md`) — must be the explicit enforcement point, not assumed.
+- Stream-zap recipient semantics (single author vs NIP-53 zap splits) needs a decision.
+
+---
+
+## Overview
+
+Bring NIP-53 Live Streaming to Amethyst **Desktop** as a **consumption + discovery** feature:
+find who/what is live, open a stream, watch the HLS video, read + post live chat, and zap.
+**Broadcasting is out of scope.**
+
+Quartz has the full NIP-53 protocol; `commons/` has the `LiveActivitiesChannel` model +
+top-zappers aggregation; Desktop ships an HLS-capable player (kdroidFilter, MIT); Android has a
+complete consumer UX to copy. This plan is **wiring + Desktop-native layouts + closing real gaps**
+(cache/channel routing for 30311/1311; live-vs-VOD player handling + stall recovery; online-probe
+extraction; a full-window watch host).
+
+Four surfaces (decided in the brainstorm):
+1. **Per-column "live now" bar** — pinned above a feed column, scoped to that column's audience;
+   one host (ranked by viewers) + `+N live ›`.
+2. **Discover integration** — a Lives section + search folded into the existing Discover (no
+   standalone sidebar destination).
+3. **Full-window watch screen** — HLS player (left) + kind-1311 chat (right) + metadata/zap.
+4. **Zaps** — zap the stream (30311 address) + chat messages (1311).
+
+Statuses: **live + planned + ended (recording/VOD)**. Profile gets a **Streams tab**.
+
+---
+
+## Problem Statement / Motivation
+
+Desktop has **zero** NIP-53 UI today while Android is mature and zap.stream has set the "live bar
+ watch-with-chat" expectation. Live streaming is high-engagement; Desktop's large screen suits a
+side-by-side watch+chat layout mobile can't match. Clear parity gap with heavy reuse leverage.
+
+---
+
+## Proposed Solution (high level)
+
+- **Reuse** Quartz protocol + `commons` model/aggregator/player/zap infra.
+- **Extract pure ranking/status/freshness logic** to `commons/.../nip53LiveActivities/`
+  (shared by Android + Desktop); keep each platform's filter thin over its own cache.
+- **Close the gaps:** stand up Desktop's first channel cache + route 30311/1311; extract the
+  online-probe to a shared source set; add a live-vs-VOD player mode + stall/reconnect watchdog;
+  add a real full-window watch host.
+- **Build Desktop-native** surfaces: per-column live bar, Discover Lives section + search,
+  full-window watch screen, profile Streams tab, event-driven planned reminders.
+
+---
+
+## Technical Approach
+
+### Architecture & reuse map
+
+**Reuse as-is — Quartz (`quartz/.../nip53LiveActivities/`):** `streaming/LiveActivitiesEvent.kt`
+(kind 30311; `checkStatus()` 8h live→ended; `LiveStreamLike`), `chat/LiveActivitiesChatMessageEvent.kt`
+(kind 1311; builders `.message(content, hint)` / `.reply(content, replyingTo)`), tag parsers under
+`streaming/tags/`.
+
+**Reuse as-is — commons:** `model/nip53LiveActivities/LiveActivitiesChannel.kt` (CLI-safe: address,
+creator, `info`, `presenceNotes`, `pruneStalePresence`), `nip53LiveActivities/LiveActivityTopZappersAggregator.kt`
+ `viewmodels/LiveStreamTopZappersViewModel.kt`, `nip53LiveActivities/ui/StreamSystemCard.kt`,
+feed DAL (`ui/feeds/`), `viewmodels/FeedViewModel.kt` + `ListChangeFeedViewModel`.
+
+**Extract Android → commons (pure logic only):** `convertStatusToOrder` + the
+`compareBy(status, participantCount, allParticipants, startTime, idHex).reversed()` comparator from
+`amethyst/.../discover/nip53LiveActivities/DiscoverLiveFeedFilter.kt:116-134` → new
+`commons/.../nip53LiveActivities/LiveActivitySorting.kt`. Freshness cutoff + viewer/follow ranking
+from `HomeLiveFilter.kt`. **Keep the `MeetingRoom`/`MeetingSpace` branches intact** (Android
+audio-rooms callers depend on the same helper) or provide a `LiveActivitiesEvent`-only overload.
+`HomeLiveFilter` (extends amethyst-only `AdditiveComplexFeedFilter<Channel,Note>`) is **not**
+portable — extract only its helpers.
+
+> ⚠️ **Correction 1 — `OnlineChecker` is an extraction, not a reuse.** It lives only in
+> `amethyst/src/main/.../service/OnlineCheck.kt` and hard-depends on **`android.util.LruCache`**
+> (won't compile in `jvmAndroid`). Task: **move it to `commons/jvmAndroid`, swapping `LruCache`
+> for a KMP-safe bounded cache** (existing `LargeCache`/`KmpLock` primitives). It already exposes
+> a `(String) -> OkHttpClient` factory + a **5-min TTL, 100-URL LRU** with same-URL dedup — reuse
+> those. Confirm Desktop supplies an OkHttp client factory (route it through the **proxy-aware**
+> `RoleBasedHttpClientBuilder.okHttpClientForVideo` — see Security). OkHttp is banned in
+> `commonMain` (`verifyKmpPurity`), so `jvmAndroid` is the correct home.
+
+### Player: live-vs-VOD + stall recovery (kdroidFilter 0.11.4 reality)
+
+The engine collapses every backend's live signal into `duration == 0.0` and exposes **no** live
+flag / buffered ranges / (Win+Mac) stall detector. Therefore:
+
+- **Classify live/VOD from NIP-53, not the player.** Use the 30311 `status` tag as source of truth
+  (`live`/`planned`/`ended`). Use `duration == 0.0` only as a corroborating hint (it's ambiguous
+  with "still loading"). For precise *ended* detection, optionally fetch the `.m3u8` and check
+  `#EXT-X-ENDLIST` (RFC 8216) — resolve a variant first if it's a master playlist.
+- **Live mode UI:** suppress the seek `Slider` (extend `VideoControls`' existing `viewMode` param;
+  `seekTo` is inert at `duration<=0` so this is safe), show a **"● LIVE" pill** (with hysteresis),
+  no `current/duration` row. "Jump to live" = `stop()` + `openUri(url)` (re-open lands at the edge).
+  Read viewer count from 30311 `current_participants`, not client-side.
+- **Own stall watchdog (mandatory Win/Mac):** sample `currentTime` ~every 1s; if `isPlaying` but no
+  advance for ~1.25–2s → stalled. OR it with Linux's `isLoading`. Reconnect via `stop()`+`openUri`
+  with bounded exponential backoff + jitter (~1s→cap ~8–30s). **Do not trust** `onPlaybackEnded` /
+  AVFoundation's `DidPlayToEndTime` for "ended" (false-fires on live). Terminal "Stream ended/offline"
+  card only on an authoritative signal (`status=ended`, stale-`live` fallback, or `#EXT-X-ENDLIST`).
+- **VOD path** (ended streams' `recording`) keeps the existing seekable controls unchanged — the
+  *easy* path.
+
+> ⚠️ **Player singleton is a real latent bug.** `GlobalMediaPlayer` is an `object`; `playVideo`/
+> `seek`/`volume`/`toggle` are **not synchronized** (only engine init is). Two callers (NowPlayingBar
+> feed video + LiveWatch) racing `playVideo(urlA/urlB)` do unguarded RMW on the same engine → torn
+> state. **Serialize player mutations behind a `Mutex`/`initLock`.** Also: `videoState` updates
+> ~60×/sec (position) and callers `collectAsState()` the whole struct → 60/s recompose churn.
+> **Split `position` out** (pass `() -> Float` / a separate `StateFlow<Float>` to the slider); in
+> **live mode read no position at all** (seek bar suppressed) → zero churn on the common path.
+> Watch-close `DisposableEffect` must stop playback, cancel the sync job, and reset
+> `MediaPlaybackState` so stale duration/position doesn't leak into a later VOD/feed video.
+
+### Data flow: channel cache + routing (the other gap)
+
+> ⚠️ **Correction 2 — Desktop has no channel abstraction.** `DesktopLocalCache.getAnyChannel()`
+> returns `null` ("Desktop doesn't support channels yet"). Routing 1311 requires **standing up the
+> first Desktop channel cache**, not just two `when` cases:
+> - Add `DesktopLocalCache.liveChatChannels = LargeCache<Address, LiveActivitiesChannel>` +
+>   `getOrCreateLiveChannel(address)` (mirror Android; keep it **live-activity-only**, don't port
+>   the 7-type Android abstraction).
+> - **30311** → `AddressableNote` in `addressableNotes` with `existing.createdAt >= event.createdAt`
+>   supersession (replaceable ⇒ one entry/stream; bounded, safe). Attach `info` to the channel.
+> - **1311** → attach to its stream's channel `notes` by root `a` tag.
+> - **`LocalRelayStore` hydration policy** (Desktop-only write-through SQLite Android lacks):
+>   **hydrate 30311** (replaceable, bounded), **skip 1311** (avoid unbounded chat replay).
+
+> ⚠️ **Desktop has no pruning today.** `pruneOldMessages()` (caps `channel.notes` to 500 newest,
+> emits `SetDeletion`) exists on the model but **nothing calls it on Desktop** (no `CachePruner`/
+> `MemoryTrimmingService`). Add a trigger: prune when the 1311 bundler tick sees `notes.size > 500`;
+> `pruneStalePresence(now - 20min)` for presence; **evict the channel's `notes` on watch-close** so
+> watching 5 busy streams doesn't retain 5×∞.
+
+### Chat: one coalescing pipeline (reuse, don't hand-roll)
+
+Route 1311 through the **existing** `ListChangeFeedViewModel` → `FeedContentState` path (same as
+Android's `ChannelFeedViewModel`/`ChannelFeedFilter`). The **250ms `BasicBundledInsert`** already
+coalesces hundreds of arrivals into ~4 list emissions/sec; stable `key = { it.idHex }`; list capped
+at `limit()=500`. The pipeline order: **ingest → dedup by event id (multi-relay dups) → moderate
+(mute/block + spam) → classify (message vs zap tier) → batch (250ms; bump to 300–500ms if jank) →
+ring-trim (500, only while at bottom) → commit one immutable list → `LazyColumn(reverseLayout=true,
+key=id, @Immutable rows)` → auto-scroll**.
+- Auto-scroll: stick to bottom only while at/near bottom (`derivedStateOf` on
+  `firstVisibleItemIndex==0 && offset<threshold`); floating "↓ N new" pill when scrolled up;
+  **`yield()` before `animateScrollToItem(0)`** (layout-race fix). Desktop: **hover-to-pause**
+  auto-scroll (mouse-first).
+- Reuse the existing desktop `ChatPane.kt` (already `reverseLayout` + auto-scroll) as the template.
+- **Note:** `DesktopCacheEventStream` is `DROP_OLDEST` (buffer 64) → chat may gap under sustained
+  burst (acceptable for chat) **but the 30311 metadata refresh must not share that lossy stream**
+  (never drop a status→live/ended transition).
+
+### Pinned chat + inline zaps
+- **Pinned** messages come from 30311 `["pinned", "<1311 id>"]` tags (host-controlled, we're already
+  subscribed to 30311) → resolve to the 1311 and render a sticky banner above the list. *(Nice-to-have;
+  keep if cheap.)*
+- **Zaps inline**: model rows as a sealed `ChatRow.Message | ChatRow.Zap(amountSats, zapper, comment)`;
+  amount from the 9735 receipt's bolt11; amount-based visual tier. Same id-dedup as messages.
+
+### Watch-screen host
+
+> ⚠️ **Correction 3 — there is no window-level overlay host.** `DesktopScreen`/`navState`/
+> `OverlayContent` are **per-column** (`navState = remember(column.id)`), so in **deck mode** a push
+> lands in a ~400px column — exactly the side-by-side-impossible layout the brainstorm rejected.
+> Only **single-pane** mode's overlay `fillMaxSize()`. **Decision needed (blocks Phase 3):**
+> - **(a) ✅ CHOSEN** — Add a genuine window-level overlay host at the `App()`/composition root in
+>   `Main.kt` (above both `DeckColumnContainer` and `SinglePaneLayout`), app-scoped nav state. The
+>   watch screen spans the whole window (player left / chat right). This is the first true full-window
+>   route — new app-scoped nav state, **not** the per-column `ColumnNavigationState`.
+> - (b) Separate top-level Compose `Window` — not chosen.
+> - (c) Single-pane overlay + max-width column — not chosen.
+
+### State-holder placement
+Per `commons/ARCHITECTURE.md`: the watch/chat **state holder** (chat list assembly, status,
+zapper wiring) goes in **`commons/viewmodels`** (reuse `LiveStreamTopZappersViewModel`); only the
+Compose screen + subscription wiring live in `desktopApp`. `LiveActivitySorting.kt` (CLI-safe pure
+logic) sits beside `LiveActivityTopZappersAggregator.kt` in `commons/.../nip53LiveActivities/`.
+
+### Sort stability
+`LiveActivitySorting` must take a **pre-snapshotted** `Map<Note,Int>` of comparator keys (status
+**and** the volatile `current_participants` — the desktop bar sorts by it, more exposed than
+Android's home bar) — never a live accessor inside the comparator (else `"Comparison method
+violates its general contract"`). Unit-test with concurrent mutation during sort.
+
+### Integration points (verified file:line)
+
+| Surface | File:location | Change |
+|---|---|---|
+| Column type | `desktopApp/.../ui/deck/DeckColumnType.kt:25-145` | *(no new Lives destination — folded into Discover)* |
+| Per-column live bar | `desktopApp/.../ui/FeedScreen.kt` (above feed `LazyColumn`; `feedMode` @~649) | insert `LiveNowBar(scope=feedMode)` pinned header (Following/Global; see scope note) |
+| Discover Lives + search | `desktopApp/.../followpacks/ui/DiscoverScreen.kt:79-265` | add Lives section + client-side search box |
+| Profile Streams tab | `desktopApp/.../ui/UserProfileScreen.kt` (tabs ~1191, `when` ~1249) | add "Streams" tab #11 |
+| Watch host | `Main.kt` App root / new window | per Correction 3 |
+| Cache routing | `desktopApp/.../cache/DesktopLocalCache.kt` `route()` | 30311/1311 + `liveChatChannels` + prune trigger |
+| Player | `desktopApp/.../ui/media/{DesktopVideoPlayer,VideoControls}.kt`, `service/media/GlobalMediaPlayer.kt` | live mode + watchdog + `Mutex` + position split |
+| Zap | `desktopApp/.../ui/NoteActions.kt` (`zapNote`, `ZapAmountDialog`) | target 30311 addr + 1311 |
+| Subscriptions | `desktopApp/.../subscriptions/SubscriptionUtils.kt` (`rememberSubscription`) | `{kinds:[30311]}` discovery, `{kinds:[1311],#a}` watch |
+| Online probe | extract → `commons/jvmAndroid` | per Correction 1 |
+
+### Implementation Phases
+
+#### Phase 0 — De-risking spikes (do first; some are now blocking)
+- **Live HLS spike:** point `DesktopVideoPlayer` at a real live zap.stream `.m3u8`; confirm
+  `duration==0.0` on live, seek no-op, error surface on a dead stream; prototype the stall watchdog
+  + `stop()`+`openUri` reconnect. Validate on macOS at minimum; note Win/Mac lack a native stall flag.
+- **Watch host decision** (Correction 3): choose (a)/(b)/(c) — **blocks Phase 3**.
+- **`OnlineChecker` extraction** (Correction 1): move to `commons/jvmAndroid`, swap `LruCache`,
+  confirm Desktop OkHttp factory + proxy-aware routing.
+- **Deliverable:** spike note in `desktopApp/plans/`.
+
+#### Phase 1 — Data layer (commons + desktop cache)
+- `commons/.../nip53LiveActivities/LiveActivitySorting.kt` — pure status-order + freshness +
+  viewer/follow ranking, **snapshot-map API** (+ unit tests incl. overdue-planned, zombie-live→ended,
+  latest-per-address dedupe, host-I-follow vs participant, concurrent-mutation). Refactor Android
+  filters to call it (hard AC — prevents drift).
+- `DesktopLocalCache`: `liveChatChannels` + `getOrCreateLiveChannel`; route 30311 (supersession) +
+  1311 (attach); prune trigger (cap 500 + `pruneStalePresence(20min)`); `LocalRelayStore` hydration
+  (30311 yes, 1311 no).
+- Desktop filters: `DesktopLiveActivityDiscoverFilter` (status LIVE>PLANNED>ENDED + online-downgrade +
+  viewer sort) and `DesktopLiveNowFilter` (follows + 15-min fresh + rank by `current_participants`).
+
+#### Phase 2 — Discovery + per-column live bar
+- `LiveNowBar` composable: single host (ranked by `current_participants`, snapshotted) + `+N live ›`;
+  scoped by column `feedMode`; **online-gated (one probe loop, visible-only, reuse 5-min LRU)**;
+  immutable `StateFlow` + `distinctUntilChanged` (no recompose when ranking unchanged); pinned above
+  the feed `LazyColumn`. **Scope: Following + Global columns** (see note); generalize later.
+- Discover Lives section + client-side search (title/host/hashtag over cached 30311s) — grid of
+  live + planned + VOD cards with `LiveFlag`/`ScheduledFlag`/"starts in…" badges. No standalone
+  sidebar destination.
+
+#### Phase 3 — Watch screen (player + chat + zap)
+- `LiveWatchScreen(address)` in the chosen host: player (live mode, watchdog, no seek bar) left;
+  chat pipeline right (read/post via `.message`/`.reply`); header (title, host, participant roles,
+  viewer count, status badge, live metadata bound to StateFlow). Online-probe before mount → offline/
+  ended placeholder (play `recording` VOD if present). Mid-watch transitions: live→ended banner
+  (disable composer, offer recording; never auto-close); URL rotation → re-point player.
+- Zap **the stream** (30311 addr); reuse `ZapAmountDialog`. **Decide zap recipient semantics**
+  (single author vs NIP-53 zap splits). Disable-with-reason when no LN address / NWC not connected.
+  Chat mute/block filtering is the enforcement point (memory `desktop_moderation_safety.md`).
+  **Per-message chat zap + top-zappers header are deferred to v1.5** (chat still renders inline zap
+  rows received from relays — just no zap-a-message action / leaderboard).
+- 2nd-stream-open + close teardown: cancel both subscriptions + reset player before mounting next.
+
+#### Phase 4 — Profile Streams tab + planned badge
+- `UserProfileScreen` "Streams" tab: user's 30311s (live + past; VOD via `recording`). **Kept in v1.**
+- Planned streams: **"starts in…" badge only** (nearly free; reuse `ScheduledFlag`). Overdue-planned
+  relabeled/downranked. **"Remind me" notify machinery is deferred** (no OS scheduler; event-driven
+  in-app-only had low hit-rate — revisit when an OS-notification path lands).
+
+#### Phase 5 — Polish, tests, format
+- Reuse `MaterialSymbols.Videocam` (no new codepoint → **no font subset regen**); LIVE badge = red
+  dot + text.
+- Unit tests (see Phase 1). `./gradlew spotlessApply`; compile `commons` (JVM+iOS purity),
+  `desktopApp`, `amethyst`, `cli`.
+- Manual testing sheet `desktopApp/plans/2026-08-20-live-media-manual-testing.md` (Linux GStreamer note).
+
+### Optional v1 trim (simplicity review — user decision)
+
+The simplicity reviewer recommends a smaller v1 (some items conflict with brainstorm choices — flagged
+for you, **not** auto-applied): live bar on **Following/Global only** (already adopted above; the
+per-`feedMode` scoping for hashtag/list/search columns is the riskiest part); **defer** the Profile
+Streams tab; **cut** planned "Remind me" (fires only when app is open + stream happens to flip live —
+high plumbing-to-payoff, gated on absent OS scheduler; keep the passive badge); **defer** per-message
+chat zap + top-zappers header + host-pinned. Core loop (find → watch → chat → zap-stream + VOD)
+survives every cut. See Open Questions.
+
+---
+
+## Alternative Approaches Considered
+- **Watch as a deck column** — rejected (400px can't hold side-by-side video+chat).
+- **Standalone "Lives" sidebar destination** — removed; brainstorm chose *fold into Discover*.
+- **Single global sidebar "Live Now"** — rejected for per-column contextual bar.
+- **New player dep (VLCJ/ffmpeg)** — rejected: VLCJ is GPL (MIT-licensing rule); kdroidFilter (MIT)
+  already does HLS.
+- **NIP-50 relay search for lives** — deferred; v1 search is client-side over cached 30311s.
+- **Hand-rolled chat throttling** — unnecessary; the 250ms `BasicBundledInsert` already exists.
+
+---
+
+## System-Wide Impact
+
+### Interaction graph
+Discover/bar → subscribe `{kinds:[30311]}` → `DesktopLocalCache.consume` builds `LiveActivitiesChannel`
+→ filters scan cache → cards render. Open card → watch host → `GlobalMediaPlayer.playVideo(streaming())`
+(serialized) + `rememberSubscription(1311,#a)` → chat pipeline → `zapNote()`.
+
+### Error & failure propagation
+- Dead `status=live` → probe false → offline placeholder (never a spinner). Player stall → watchdog
+  → "Reconnecting…" → Retry. Player error → scheme-checked "Open in default player" fallback.
+- Zap failure → existing `ZapFeedback.Error/Timeout` snackbar. No relays → `rememberSubscription`
+  returns null (no crash).
+
+### State lifecycle risks
+- **Cache growth (1311 unbounded):** Desktop has no prune — add the trigger (cap 500) + evict on
+  watch-close. 30311 bounded (replaceable). Presence pruned at 20-min cutoff.
+- **Player singleton:** race (fix with `Mutex`) + 60/s position churn (split position out; live mode
+  reads none) + source-switch must reset `MediaPlaybackState`.
+- **Reminder persistence:** expire dormant reminders.
+- **Lossy event stream** (`DROP_OLDEST`): fine for chat; 30311 metadata must not share it.
+
+### API surface parity
+- Android + Desktop share `LiveActivitySorting` (hard AC → no ordering drift). `amy` CLI out of scope
+  for v1, but the shared helper makes a future `amy lives` cheap.
+
+### Integration test scenarios
+1. Two follows live → bar shows higher-`current_participants` + "+1 live ›".
+2. `status=live` but `.m3u8` dead → treated offline (probe), not shown live.
+3. Post chat → 1311 with correct root `a` tag → appears; muted author's messages filtered.
+4. Zap stream → request carries 30311 `a` tag → receipt attributed to stream (recipient per decision).
+5. Planned flips live while app open → reminded user gets in-app snackbar.
+6. Ended stream with `recording` → VOD plays with normal seekable bar.
+7. live→ended mid-watch → end banner, composer disabled, "Play recording" offered, no auto-close.
+8. Open 2nd stream while watching → first's player+subscription torn down before second mounts.
+
+---
+
+## Acceptance Criteria
+
+### Functional
+- [ ] Discover has a **Lives** section + client-side search (title/host/hashtag over cached 30311s).
+- [ ] Each **Following/Global** feed column shows a pinned live-now bar: one host (ranked by
+      `current_participants`) + `+N live ›`; hidden when none live.
+- [ ] Opening a live shows a **full-window watch screen** (chosen host): live player (**no seek bar**,
+      LIVE pill, stall→reconnect watchdog) left + kind-1311 chat right + header (title/host/roles/
+      viewer count/status).
+- [ ] Live metadata (title/roles/viewer count/status) updates live as the 30311 is re-published.
+- [ ] User can **read + post** live chat; posts are 1311 with the correct root `a` tag; chat filters
+      **muted/blocked** authors (private + public) and re-filters on live mute-list change.
+- [ ] Chat composer disabled-with-reason when: stream ended, logged out, or send in flight/failed
+      (draft preserved).
+- [ ] User can **zap the stream** (recipient semantics defined); disabled-with-reason when no LN
+      address / NWC not connected. (Per-message chat zap deferred to v1.5.)
+- [ ] **Planned** streams show a "starts in…" badge; overdue-planned relabeled/downranked.
+- [ ] **Ended** streams with `recording` play as **VOD** (seekable); ended-without-recording shows a
+      non-playable "no recording" state everywhere it can appear.
+- [ ] Profile has a **Streams** tab (user's live + past streams).
+- [ ] Mid-watch `live→ended` shows an end banner, disables composer, offers recording; never auto-closes.
+- [ ] Streaming-URL change or mid-playback stall re-points/reconnects → offline+Retry, never a frozen frame.
+- [ ] Opening a 2nd stream cleanly tears down the first (both subscriptions + player) before mounting.
+- [ ] Direct naddr/nevent open resolves + fetch-first (loading→branch); unknown/not-found handled, no hang.
+
+### Non-functional
+- [ ] Chat UI ≤ 4 list updates/sec (250ms bundler); list ≤ 500 rows; no recompose storm.
+- [ ] Live-bar recompose only when top-host/count changes (immutable `StateFlow` + `distinctUntilChanged`).
+- [ ] ≤ 1 network HEAD per `.m3u8` per 5 min; visible-only probing; one poll loop (not per-card).
+- [ ] Player mutations serialized; position ticks don't recompose header/chat; live mode reads no position.
+- [ ] Player + "Open in default player" both gated by a URL-scheme allowlist (https only; block
+      `file://`/`smb://`/custom schemes); probe routed through the proxy-aware client; probe-on-intent,
+      not on discovery.
+- [ ] Chat text sanitized (bidi controls escaped per repo rule / CVE-2021-42574; no remote auto-load
+      abuse); participant `proof` verified before showing a claimed role (`hasValidProof`).
+- [ ] No new copyleft dependency (player stays kdroidFilter MIT).
+
+### Quality gates
+- [ ] Unit tests: status order, freshness, ranking, offline-downgrade, overdue-planned, zombie-live,
+      latest-per-address dedupe, concurrent-mutation sort stability.
+- [ ] `commons` JVM + iOS-purity, `desktopApp`, `amethyst`, `cli` compile; `spotlessApply` clean.
+- [ ] Manual testing sheet executed on macOS (+ Linux GStreamer note).
+
+---
+
+## Dependencies & Risks
+- **Live `.m3u8` handling + stall recovery** — highest risk; Phase 0 spike. Win/Mac have no native
+  stall flag → app-level watchdog mandatory.
+- **Channel cache is new on Desktop** — first channel abstraction + first prune trigger; core-file change.
+- **Player singleton race** — fix before shipping (Mutex).
+- **Watch host** — no window-level host exists; pick (a)/(b)/(c) in Phase 0.
+- **Mute/block in chat** — known Desktop silent-no-op gap; must not regress.
+- **No OS scheduler** — "Remind me" is in-app/event-driven only.
+- **Linux runtime** — GStreamer required (documented in `desktopApp/build.gradle.kts`).
+
+---
+
+## Non-Goals / Deferred
+Broadcasting; audio rooms / Nests (30312/10312); raids (`LiveActivitiesRaidEvent`); clips
+(`LiveActivitiesClipEvent`); zap-goal progress bar + zap-to-highlight (fast follow — `goal` tag
+parsed); OS-level/system-tray notifications; `amy` live verbs; PiP/mini live-player; NIP-53 `proof`
+signature *generation*; per-column bar on hashtag/list/search columns (v2).
+
+---
+
+## Open Questions
+
+**Blocking (resolve in Phase 0):**
+1. **Watch host** — (a) app-root overlay [recommended] / (b) separate `Window` / (c) single-pane +
+   max-width column?
+2. **Live signal** — confirm `duration==0.0` on real live `.m3u8` across backends; is manifest
+   `#EXT-X-ENDLIST` fetching worth it for precise ended, or rely on `status=ended`?
+3. **Stream-zap recipient** — single 30311 author, or honor NIP-53 zap splits / `p`-tag recipient?
+
+**Scope (RESOLVED 2026-08-20):**
+4. Profile Streams tab → **kept in v1**.
+5. Planned "Remind me" → **badge-only in v1** (notify machinery deferred).
+6. Per-message chat zap + top-zappers header → **deferred to v1.5**.
+7. Watch host → **(a) app-root overlay host** (also blocking Q1 above).
+
+**During work:**
+7. Chat windowing vs virtualization — confirm the 250ms-bundler + 500-cap path suffices (likely yes).
+8. Search — client-side for v1; NIP-50 relay search later?
+
+---
+
+## Sources & References
+
+### Origin
+- **Brainstorm:** [docs/brainstorms/2026-08-20-feat-desktop-live-media-brainstorm.md](../brainstorms/2026-08-20-feat-desktop-live-media-brainstorm.md)
+  — carried forward: per-column live bar (one host + `+N`, viewers-ranked); lives folded into Discover
+  + search; full-window watch+chat; zaps in v1; live+planned+VOD; Streams tab; planned "Remind me";
+  online HEAD-probe.
+
+### Internal (verified file:line)
+- Quartz `nip53LiveActivities/{streaming/LiveActivitiesEvent, chat/LiveActivitiesChatMessageEvent, LiveStreamLike}.kt`, `streaming/tags/`.
+- commons `model/nip53LiveActivities/LiveActivitiesChannel.kt`, `nip53LiveActivities/{LiveActivityTopZappersAggregator, ui/StreamSystemCard}.kt`, `viewmodels/{FeedViewModel, LiveStreamTopZappersViewModel}.kt`, `ui/feeds/`, `ARCHITECTURE.md`, `build.gradle.kts` (`verifyKmpPurity`).
+- Android `home/dal/HomeLiveFilter.kt`, `home/live/{RenderLiveActivityBubble,LiveStatusIndicator}.kt`, `discover/nip53LiveActivities/DiscoverLiveFeedFilter.kt:116-134`, `livestreams/dal/LiveStreamsFeedFilter.kt`, `note/types/{LiveActivity,LiveActivityChatMessage}.kt`, `chats/publicChannels/nip53LiveActivities/*`, `service/OnlineCheck.kt` (android-only, `LruCache`), `AccountViewModel.checkVideoIsOnline`.
+- Desktop `ui/deck/{DeckSidebar,DeckColumnType,DeckColumnContainer,DeckState,SinglePaneLayout}.kt`, `ui/{FeedScreen,ReadingColumn,UserProfileScreen,SearchScreen,ChatPane}.kt`, `followpacks/ui/DiscoverScreen.kt`, `ui/media/{DesktopVideoPlayer,VideoControls}.kt`, `service/media/GlobalMediaPlayer.kt`, `ui/NoteActions.kt`, `nwc/NwcPaymentHandler.kt`, `cache/DesktopLocalCache.kt` (`getAnyChannel`→null, `route()`, `addressableNotes`), `subscriptions/SubscriptionUtils.kt`, `Main.kt` (`DesktopScreen` per-column), `DesktopPreferences`.
+- Build: `gradle/libs.versions.toml` (`composemediaplayer = 0.11.4`, MIT).
+- Memory: `desktop_moderation_safety.md` (mute/block enforcement gap).
+
+### External
+- NIP-53: https://github.com/nostr-protocol/nips/blob/master/53.md
+- zap.stream: https://github.com/v0l/zap.stream
+- kdroidFilter ComposeMediaPlayer: https://github.com/kdroidFilter/ComposeMediaPlayer (issues #244 buffered-ranges, #173 HLS Win/Mac, #77 403→blank)
+- RFC 8216 (HLS) `#EXT-X-ENDLIST`/`PLAYLIST-TYPE`: https://www.rfc-editor.org/rfc/rfc8216.html
+- Mux HLS ext tags: https://www.mux.com/articles/hls-ext-tags
+- Twitch chat rendering perf: https://blog.twitch.tv/en/2016/08/08/improving-chat-rendering-performance-1c0945b82764/
+- video.js live guide: https://videojs.com/guides/live/ · hls.js gap-controller: https://github.com/video-dev/hls.js/blob/master/src/controller/gap-controller.ts
+- Safer flow collection: https://medium.com/androiddevelopers/a-safer-way-to-collect-flows-from-android-uis-23080b1f8bda