Files
jellytau/docs/specs/README.md
T
dtourolle bed1030443 feat(android): play the original file — decode Dolby/DTS audio with FFmpeg
Android ships no AC-3, E-AC-3, DTS or TrueHD decoders; they are licensed
codecs, present only where a vendor paid for them. The ROD2-W09 tablet has a
vendor DTS decoder and no AC-3/E-AC-3 at all. So every film with Dolby audio
was re-encoded by the server, for streaming and for download alike, and a
transcoded download has no Content-Length and ignores Range: ~1 MB/s,
restarting from byte zero on every network blip.

ExoPlayer now carries Jellyfin's media3 FFmpeg audio decoder in extension
mode ON (platform decoders first, FFmpeg for what they lack), and
CodecDetector reports its codecs so the device profile and the download
policy agree with what actually decodes. The download policy judges audio
against the renderer that will play the file (renderer_can_decode_audio)
instead of the webview's list, so Android downloads are always the direct
copy — a 910 MB E-AC-3 5.1 episode downloaded in 94 s and played offline.

The webview video path is removed on Android: it decodes none of these
codecs, so a stored "native video off" would play every original-file
download silent. Rust reports webview_video_fallback (false on Android, true
only beside mpv native video on Linux); Settings offers the switch and the
player honours it only then. Linux keeps the fallback and, with it, the
server transcode for undecodable audio.

The decoder is GPL-3.0; the distributed APK carries its terms and the source
stays MIT (THIRD_PARTY_NOTICES.md). The on-device remux spec this replaces is
folded into 05-platform-backends.md and deleted.

DR-293, UT-259, UT-262.
2026-09-22 22:22:05 -04:00

7.3 KiB

Specs index

Feature specs for JellyTau. Start a new one from SPEC-TEMPLATE.md and run it past SPEC-REVIEW-CHECKLIST.md before accepting it.

What lives here

Only work that has not shipped. Once a spec is fully implemented its design is folded into the architecture docs — which are the maintained description of the build — and the spec file is deleted. Git history keeps the original, including its rejected alternatives and acceptance criteria; the architecture docs keep the reasoning that a future change still needs.

So: a file in this directory is a promise, not a description. If you want to know how something works, read docs/architecture/. If you want to know what is planned, read here.

Status vocabulary

Status Meaning
Proposed Written, not accepted. Nothing built.
Accepted Agreed as the design; implementation not started or not finished.
Partially implemented Some parts shipped; the spec names what is left.
Design authority No code of its own — it records a decision later specs act on.

Next free requirement ids (always re-check requirements.md before allocating): UR-086, IR-036, JA-038, DR-295, UT-264 (DR-289/290 went to the v0.12.2 download fixes; DR-291/292 and UT-255/257/258 to the offline-banner and server-only-reveal work; DR-293/294 and UT-259-263 to Android's FFmpeg decoding and offline-without-network). Three specs below suggested ids that have since been taken by other work; each carries a ⚠️ note at the top — this line was itself stale by five, two and forty-seven until 2026-09-08, which is why the re-check is not optional.

Partially implemented

Spec What landed What is left
frontend-domain-model.md Catalog surface: MediaKind, from_jellyfin isolated, ticks → ms primaryImageTagimageId (~30 sites); player/session/reporting tick math; stream.type
jellyfin-server-version-compatibility.md Route table, ServerCapabilities, the auth-spelling fix (the one thing 12.0 actually breaks), explicit Recursive, cache generation stamping, the frontend route leak, the unsupported-server state, and an HTTP-level harness that runs the repository against both generations DR-283: two resolved flags are not consumed yet, and honours_directplay_audio_codec is unestablished for 12.x — both need a running 12.x server. Nothing has been tested against a real server of either generation
libmpv2-migration.md LICENSE The libmpvlibmpv2 crate swap
read-through-media-cache.md DR-126…128, DR-133…138 — cache entries are download rows; local playback of downloads DR-122/124/125 — the read-through capture. DR-121 shipped as backend-owned stream selection and left this spec
scoped-search-boundary-implementation.md Stage 1: SearchScope owned by Rust (DR-063…067) Stage 2: result-side grouping (GROUP_ITEM_TYPES still in searchScope.ts)

Not started

Spec Blocked on / note
desktop-native-video.md mpv draws video on every desktop platform, then the webview <video> path and hls.js are deleted. Converts a measured 7% direct-play rate toward Android's 85%. Stacked on backend-owned stream selection.
backend-owned-stream-selection.md Rust owns direct-play-vs-transcode, transport and quality; players consume one StreamSelection. Partly built — StreamSelection, Transport and the .m3u8 sniff removal have landed.
build-provenance.md build.rs is still bare. ⚠️ suggested id DR-093 is taken.
player-facade-enforcement.md ~60 commands.player* sites still outside the facade; no lint rule. ⚠️ suggested id DR-095 is taken.
windows-native-audio-backend.md Blocked on the libmpv2 swap. ⚠️ suggested id IR-030 is taken.
linux-native-video-spike.md Spike run 2026-08-21: compositing works on Linux, X11 and Wayland. G1-G6 green bar the Tauri default_vbox() half of G1. The adaptive-bitrate question it was waiting on is answered: the server publishes one EXT-X-STREAM-INF, so there is no ladder for mpv to lose (DR-229). StreamSelection (DR-225) is the contract to consume.

Design authority

Spec Role
playback-backend-unification.md Why video cannot unify onto one native engine and audio can. The audio half has since shipped on Android; Windows has not.
scoped-search-boundary.md The boundary design the check:boundary rule came from. Stage 1 built.
scoped-search.md Superseded in part — its "frontend only, no Rust changes" decision is the leak the boundary spec reversed. UX still current.

Where the shipped specs went

Sixteen specs were folded into the architecture docs and deleted (2026-08-21). Where to look for each:

Shipped work Now documented in
Account menu & global chrome 02-svelte-frontend.md — App Shell and Chrome
Library mosaic 02-svelte-frontend.md — Library Mosaic
Series current-episode navigation 02-svelte-frontend.md — Series and Episode Navigation
Downloads as an offline library 02-svelte-frontend.md — Downloaded Browse
Favourites browsing 01-rust-backend.md — Favorites System
Streaming bitrate cap 01-rust-backend.md — Streaming quality ladder
Locally-indexed search 03-data-flow.md — Search Flow; 01-rust-backend.md — Background workers
Offline downloaded-only filter 06-downloads-and-offline.md — Offline Catalog Visibility
Audio equalizer · Android audio settings parity 05-platform-backends.md — Audio settings on ExoPlayer
Android native video spike 05-platform-backends.md — Native Video Compositing
Video background audio 05-platform-backends.md — Background Audio Handoff
Traceability gate repair traceability-ci.md
Boundary tripwire hardening scripts/check-frontend-boundary.sh (its header is the spec)
Original-file downloads & Android FFmpeg decoding (was on-device-audio-remux) 05-platform-backends.md — Licensed audio codecs; 06-downloads-and-offline.md — What a Video Download Fetches, Offline Means No Network
Playback docs corrections · req-coverage script removal Nothing to document — both were corrections that have been applied