quest: plan the follow-ups of #81

quest/m0/README.md

@@ -103,6 +103,8 @@ repository.
 - [The program reaches a relay on every runner](/quest/m0/relay-test-flake.md) - the relay engine test stops failing the nightly on GitHub's runner
 - [Browser sources make no outside requests](/quest/m0/browser-offline.md) - no component updates, spellcheck downloads, or network time from the helper
 - [moq-studio builds on its own](/quest/m0/studio-builds-alone.md) - `cargo build -p moq-studio` no longer leans on a test dependency's features
+- [Unpublishing a scene ends its broadcast cleanly](/quest/m0/unpublish-clean.md) - viewers get a clean finish, not `Unroutable`, when a scene stops publishing
+- [A media file's sound plays with its pictures](/quest/m0/media-av-sync.md) - media sources write a bus latency ahead, as broadcast sources do
 - [The Apple signing identity is available](/quest/m0/signing.md) - the Apple credentials packaging and the macOS camera need; Windows ships unsigned
 - [Packaging](/quest/m0/packaging.md) - a signed macOS app, a Windows installer, and a Flatpak for Linux
 - [The persistable portal restore token is pinned](/quest/m0/pin-portal-token.md) - moq-video's restore token, for Wayland sources

quest/m0/media-av-sync.md

@@ -0,0 +1,20 @@
+# [S] A media file's sound plays with its pictures
+
+## Goal
+
+A media file source's sound plays in step with its own pictures in every
+output (program, published scenes, recordings, and Listen), instead of about
+45 ms behind them.
+
+## Plan
+
+From [moq-dev/studio#81](https://github.com/moq-dev/studio/pull/81), picked
+2026-11-07 (maintainer away under /afk, recommended option), m0 by the rule
+that fixes join m0.
+
+Pictures show when they are due, but a media source writes its sound to the
+bus when it is due, and the bus mixes it a bus latency (50 ms) later.
+Broadcast sources already write a bus latency ahead (`playout::Writer`);
+media sources should do the same. Test that a media file's picture change
+and its sound onset leave an output within one bus block of each other,
+measured on the media clock rather than with sleeps.

quest/m0/unpublish-clean.md

@@ -0,0 +1,24 @@
+# [S] Unpublishing a scene ends its broadcast cleanly
+
+## Goal
+
+When a scene is unpublished, renamed, or removed, its viewers receive the
+end of each track as a clean finish, never an `Unroutable` error, and
+`a_published_scene_has_its_own_broadcast` passes every time.
+
+## Plan
+
+From [moq-dev/studio#81](https://github.com/moq-dev/studio/pull/81), picked
+2026-11-07 (maintainer away under /afk, recommended option), m0 by the rule
+that fixes join m0.
+
+The studio closes a scene's broadcast as soon as its encoders finish their
+tracks locally, so the relay can unroute it before a track's end reaches the
+viewer. The test above failed 3 times in about 33 runs on a loaded host from
+this race. Quitting already waits until the relay has what it was sent
+(`Output::close` in `rs/moq-studio/src/engine.rs`).
+
+- ✅ **Unpublishing waits the same way** before it closes the broadcast.
+  Rejected for now: changing moq-net to deliver a finished track's end after
+  its broadcast closes, which would land upstream first and is only worth it
+  if the studio's wait cannot cover every case.