Files
jellytau/docs/specs
dtourolle 0f928798d7 docs(specs): download the original and fix the audio on device
A Jellyfin transcode is generated as it is sent — no Content-Length, Range
ignored — so every interruption restarts it from byte zero, and three
concurrent downloads are three ffmpeg jobs on the server. Measured on the
tablet: a direct copy moves 2.06 GB in 142 s with no retries, a transcode
crawls at ~1 MB/s and cannot resume. The transcode is only ever requested
because of the audio track.

So: always fetch Static=true, and re-encode the audio on the device when the
source carries something the renderers cannot decode.

DR-171 keeps its diagnosis — a downloaded film played as picture in silence,
and offline there is no other source to fall back to — and loses its remedy,
which explicitly accepted the loss of byte-range resumability. Its other
finding survives and constrains this spec: a downloaded file outlives whatever
experimentalNativeVideo was set to when it arrived, which is why the fix is to
the bytes on disk rather than to one renderer.

Records the rejected alternatives with the specific reason each fails, and the
decision to accept HEVC staying HEVC (Android-first; recoverable by a setting,
unlike silent audio).
2026-09-22 21:00:32 -04:00
..

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-291 (DR-289/290 went to the download stall timeout and the transcode progress estimate in v0.12.2). 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.
on-device-audio-remux.md Downloads fetch the original (Static=true, resumable — measured 14× faster) and a bundled FFmpeg re-encodes only the audio on device, replacing DR-171's server-side transcode. HEVC side effect accepted (Android-first; the webview video path is being retired). Android APK size increase still to be measured.
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)
Playback docs corrections · req-coverage script removal Nothing to document — both were corrections that have been applied