5 Commits

Include renames

Author	SHA1	Message	Date
dtourolle	fecd6022fe	chore(traceability): shift this branch's ids clear of master's ... Master allocated DR-224 and UT-211 while this branch was in flight — the third collision on this work. Everything here moves up by one: DR-224..236 become DR-225..237, UT-211..213 become UT-212..214. UR-079, UR-080 and IR-033 were still free and are unchanged. Mechanical, and matched on each row's own text rather than on its number, so a row cannot be shifted twice or the wrong one caught. Master's DR-224 (the background-audio toggle) and UT-211 are untouched.	2026-08-22 13:45:04 +02:00
dtourolle	156b9e3684	fix(playback): ask the renderer what it can decode, in one place ... Four bugs, one cause. "What can this device decode" was answered in five places, four of which assumed the webview was decoding: - the device profile's direct-play codecs (cfg per platform, inline) - the transcoding targets (hardcoded "h264,hevc") - the direct-play audio narrowing (webview list, all platforms) - the client-side audio override (webview list, all platforms) - get_video_stream_url's VideoCodec (hardcoded "h264") On Android the decoder is ExoPlayer, so four of those were simply wrong there, and the costs were invisible without a device: - dts is in the tablet's own codec list, gets stripped from the profile, and is then forced to transcode by a rule about a renderer that is not playing it. - An hevc source whose *audio* is eac3 had its **picture fully re-encoded**. The server's own transcoding URL got this right — VideoCodec=h264,hevc, TranscodeReasons=AudioCodecNotSupported, video copied — but the moment a quality change or track switch re-opened the stream through our builder, the hardcoded h264 turned a cheap audio remux into a full transcode. That is a quality change silently making playback more expensive, on the exact path a viewer uses when playback is already struggling. `renderer_codecs()` and `renderer_can_decode_audio()` are now the single source, and all five sites read them. On the webview path every value resolves exactly as before, so desktop behaviour is unchanged by construction; on Android the profile becomes the device's own. The list is also what lets the server *copy* rather than re-encode: naming every codec the renderer can decode is what turns a transcode into a passthrough when the source is already playable. That is the whole of "use the best format available". Also corrects this branch's headline number where it is asserted — the architecture doc, the desktop-native-video spec and the spike. The measured 85% Android direct-play rate used a profile containing ac3/eac3; the device it was later verified on reports neither, so eac3 content correctly transcodes there. It is a ceiling for an ExoPlayer-appropriate profile, not what the app achieves, and realising any of it depends on this change. Left in place with the caveat rather than deleted, because the measurement is real — it just measures something narrower than it was quoted as measuring. Unverified: this changes what Android negotiates and has not been exercised on the tablet yet. Desktop is unchanged by construction but also unre-tested.	2026-08-22 13:45:03 +02:00
dtourolle	7cc392d78f	docs(specs): mpv draws desktop video, and the webview path goes ... The spike proved compositing works on Linux, including Wayland, and left two blockers. One is now closed: DR-228 measured a single EXT-X-STREAM-INF in the server's master playlist, so there is no adaptive bitrate for mpv to lose and finding 3 of playback-backend-unification.md is false. The spike is updated to record that. The other — an unexplained SIGSEGV in a decoder thread — is carried into the spec as DR-231 rather than chased: the spike had no render-context teardown at all, which is DR-184 on Android restated, and removing the likeliest cause is worth doing whether or not it was the cause. The spec targets every desktop platform rather than Linux alone, because the maintenance argument runs the other way. Video has three renderers today. A Linux-only version makes it four, permanently — mpv on Linux, HTML5 on Windows, ExoPlayer on Android, hls.js underneath — and the webview path then survives indefinitely because something still needs it. Finishing the job leaves mpv on desktop and ExoPlayer on Android, and hls.js, html5Adapter.ts, videoLoaderFor and the <video> element are deleted in a phase that has its own acceptance criterion so it cannot quietly become "later". The load-bearing change is DR-233: the device profile stops being a compile-time platform constant and becomes a property of the renderer that will decode the stream. The measured 7% desktop direct-play rate and Android's 85% differ by nothing except which component decodes, so that one change is what converts the former toward the latter. It looks like configuration and is not — it decides whether the server re-encodes, and it fails silently when wrong. Windows is costed rather than waved at: the surface is genuinely different code (WebView2 in an HWND, not GTK), but everything else is shared, so nothing may be guarded on cfg!(target_os = "linux"). The real cost is build — libmpv is a Linux-only dependency while Windows cross-compiles via cargo-xwin, so a Windows libmpv must reach that build and ship in the NSIS bundle under the LGPL terms DR-216 already records. Allocates UR-080, DR-230..236, IR-033. No product code yet.	2026-08-22 13:45:03 +02:00
dtourolle	99d96163d8	docs(specs): correct the spike's crash and ABR findings ... Three corrections to the Linux native-video spike, each of which reverses something recorded earlier in the same session: - The crash is unexplained. It was first blamed on hwdec=auto-safe's Vulkan failures, on a misreading of the logs — those are two per run at start-up, not per-frame, and every clean run has the same two. A 300s soak on auto-safe survived. So did 240s of automated fullscreen toggling (~120 transitions) and 240s of continuous resizing (~2000 reallocations). Three hypotheses, none reproduced. Recorded rather than dismissed: an intermittent fault nobody can reproduce is worse to inherit than a deterministic one. - G5 drops to amber. It looked and felt smooth, but the only SIGSEGV observed came from the only session in which fullscreen was exercised, and the spike has no lifecycle handling at all — it never frees the render context. An implementation must bind that to the GL context's lifetime regardless of what caused this crash, because Android already paid for that lesson as DR-184. - Finding 3's premise is in doubt. "The webview path already has real ABR via hls.js" was never checked against the URLs this app builds: get_video_stream_url requests a single rendition, the frontend has no level-handling code at all, and a quality switch is implemented by re-opening the stream. If the playlist is single-variant there is no adaptation to lose. The decisive test needs a live server and is recorded as unrun. Also records hardware decode working through the render API (nvdec-copy engaged), and that hwdec=vaapi silently fell back to software on this box.	2026-08-21 19:41:21 +02:00
dtourolle	f11f5eddd5	docs(specs): record the Linux native-video compositing spike ... Adds the spike write-up and re-opens finding 2 of playback-backend-unification.md, which concluded that video cannot unify on a native engine because the webview owns the surface. That finding's general form has since been falsified on Android, where native video composites behind a transparent WebView and ships on by default. The evidence behind it was also entirely about foreign-window embedding -- mpv's render API, drawing into a GL context we own inside Tauri's own GTK tree, was never tested. The spike tests that one claim and comes back green on Linux for both X11 and Wayland, bar the Tauri default_vbox() half of G1. Findings 3-6 are deliberately left standing. Finding 3 in particular -- mpv has no adaptive bitrate -- is an independent disqualifier that a green compositing result does not clear, and the spike says so rather than reading as a green light. The next-free-id line moves to UR-079 / IR-033 / DR-219: this branch allocated UR-077 and UR-078 for the updater and diagnostics work, and DR-215 through DR-218 with them, after that line was last written. Authored in a parallel session working in the same checkout; committed here so it travels with the rest of the branch.	2026-08-21 19:06:13 +02:00