Tunneled playback on an AFTMM judders continuously through 23.976p direct play.
The #1802 reporter isolated it: turning off Tunneled Playback with every other
setting unchanged makes it smooth, and their log shows tunneling active for the
whole session with E-AC3 bitstreamed and the decoded-PCM guard never firing.
Audio Passthrough looked like the trigger only because it is the one user-facing
switch that decides it. Passthrough off, or Downmix to Stereo on, both force the
Dolby track to decode to PCM, which trips the #1458 guard and takes tunneling
down with it. Passthrough on with downmix off is the only combination that keeps
a bitstreamed track, so it is the only one that stays tunneled.
Withdraw tunneling on that model for content at or below 30fps. The cut-off
keeps 4K50/60 tunneled, which is the workload Amazon documents the feature for.
The mechanism stays unconfirmed: tunneling fires no VideoFrameMetadataListener
and stops media3 counting frames in the codec, so nothing app-side can measure
the cadence. Only the trigger is established, and the quirk is scoped to it.
That needs a frame rate the app did not have. Neither MatroskaExtractor nor
Mp4Extractor populates Format.frameRate, and a tunneled session renders no
frames back for the native detector, so the server's rate now rides on the open
call. It is sent only for direct play, matching _primeDisplayCriteria: a
transcode's metadata describes the source, not what the server is about to send.
Also move Audio Passthrough out of the in-player settings sheet. It configures
the audio output route rather than the current playback, and applying it
mid-stream bounces the audio renderer and re-decides tunneling. Settings > Video
Playback already owns it, next to Tunneled Playback, which is applied the same
way. That description now mentions stutter, not only black HDR video, so the
workaround is findable on hardware this quirk does not cover.
The mpv backend failing to start the same 4K file is a separate defect and is
not addressed here; its uploaded log is no longer retrievable.
Episode navigation carries the subtitle choice this screen has committed, so
a way of turning subtitles off that the screen never sees is undone by the
next episode.
ExoPlayer has no renderer-level visibility switch, so the player's hide
toggle is emulated by deselecting the track. That emulation lasted until the
next selection: the automatic pass after an episode change put subtitles
straight back on screen while the toggle still read "hidden", and un-hiding
then restored a track id belonging to the episode that had already ended.
Hiding is now sticky across media opens the way mpv's global sub-visibility
is, selections made while hidden become what un-hiding restores, and the
toggle no longer refuses to restore because the hidden track reads as Off.
Cycling subtitles over the native track list — downloads, and items whose
server exposes no subtitle rows — went straight to the track manager, which
owns the player selection and the server write-back but not the committed
choice. The screen records the cycled track now.
On Auto, Dart derives a buffer size for mpv's demuxer from the device heap and
sets it as `demuxer-max-bytes`. The Android player forwarded that same number to
`DefaultLoadControl.setTargetBufferBytes`, so ExoPlayer's sample allocator was
sized by a tier table written for a different consumer: 64MB on any device whose
large heap is 512MB or less, which every Shield is.
`targetBufferBytes` is a byte cap, so the media it represents collapses as
bitrate rises — 64MB is 53s of a 10 Mbit/s stream but 5.2s of a 103 Mbit/s UHD
remux. With `prioritizeTimeOverSizeThresholds` false the cap is hard:
`shouldContinueLoading` returns false the moment the allocator reaches it no
matter how little media that is, and `shouldStartPlayback` reports READY off the
same byte term. Read-ahead that short starves the audio sink in bursts, and on a
passthrough route that is enough to keep the AudioTrack from ever starting — the
track initializes, accepts one access unit and never renders a frame. Because an
enabled audio renderer owns the MediaClock, the whole player freezes and the
black-screen watchdog then blames the video decoder and drops the session to
mpv.
Size the LoadControl target natively instead, from what actually bounds
`DefaultAllocator`: the Java heap. `min(media3's own default for a video+audio
selection, largeMemoryClass/4, availMem/4)` with a 32MB floor, the lowest tier
that has already shipped. The quarter matches the threshold the Buffer Size
setting already warns at, and the media3 default is a ceiling — this is not
"buffer more than upstream", it is "stop buffering less". Deliberately not
bitrate-aware, because the LoadControl is built during initialize, before any
media is opened. `bufferSizeAuto` carries the distinction over the channel;
`bufferSizeBytes` still travels with it because the plugin's mpv fallback
replays it as a real demuxer property, and an explicit Buffer Size choice is
still honoured verbatim.
Confirmed against the hardware in the 2.9.1 passthrough report. That reporter's
own log is a natural A/B: three runs at 64MB fail with `0 frames rendered after
8002ms`, spanning both DV conversion modes and both tunneling states, while the
single run after he manually selected 128MB logs `Position advancing` and
renders. Reproduced on the same Shield model with codec and bitrate held fixed
and only the cap varied — 6s of audio demand stalls at 64MiB and plays at
128MiB, 4 of 4 predictions, with read-ahead measured off an injected
DefaultAllocator at 65 664 and 131 776 KiB. That device reports
`dalvik.vm.heapsize` 512m, so the heap term binds first at every free-memory
level in his log and Auto now derives exactly the 128MB he had to pick by hand;
the shipped path logs `Buffer: 128MB limit (auto, heap=512MB, available=568MB)`
where it previously logged 64MB.
A 404 on the media stream means the server resolved the item but could not
open the file behind it — moved, deleted, or on storage that went away.
Jellyfin maps the resulting FileNotFoundException to 404, and PlaybackInfo
never stats the file, so negotiation succeeds and only the stream request
fails. Playback then died with a snackbar reading "Failed to open
[REDACTED_URL]" before popping the route, which tells the user nothing and
leaves nothing useful in a bug report.
Generalize the HTTP-500 log probe into PlayerError.httpStatusFromLog and
latch every status in fatalPlaybackHttpStatuses. Each latches on its own so
the 503 that stream-lavf-o deliberately retries cannot mask the fatal status
behind it. A 404 now raises a dedicated modal naming the cause and the fix.
On Android a 404 previously failed the "Response code: 500" string test and
fell through to the ExoPlayer→MPV fallback, showing "switching to compatible
player" before failing again on the same request. Read the real status off
HttpDataSource.InvalidResponseCodeException instead and skip the fallback:
an HTTP status is not a codec problem.
Audio passthrough defaults on for Android TV, scoped to ExoPlayer because
mpv force-passes through every codec named in audio-spdif and has no
decode fallback. That scoping did not survive the ExoPlayer to mpv
handoff: PlayerAndroid queued the raw ac3,eac3,dts,dts-hd,truehd list as
a pending mpv property and prepareMpvFallback replayed it verbatim, so a
sink that bitstreams only Dolby formats was told to force TrueHD and
DTS-HD anyway. mpv selected spdif_truehd, the audio output never
initialised, and playback froze at its start position while still showing
a first frame — the stop timeline reported the position it opened with.
Treat passthrough as a request and resolve the codec list against the
route when mpv actually starts, so an HDMI or AVR change between
ExoPlayer startup and the handoff cannot replay codecs from the old sink.
Gate each codec on the exact advertised encoding rather than media3's
passthrough probe: that probe answers DTS-HD by downgrading to the DTS
core, and mpv reads "dts,dts-hd" as "dts-hd" alone, so accepting the
downgrade would name DTS-HD MA to a core-only receiver and lose DTS too.
setNext() appended raw content:// URIs that mpv cannot open, stalling
playback at the SD-card-download track boundary. Convert to fdclose://
like open(), track the armed fd, and reclaim it via a new closeContentFd
method when the entry is dropped unplayed (close only when provably
unconsumed — playlist-pos 0 before and after the remove; leak on doubt).
The playlist-pos pre-check also keeps the clear path from removing the
playing entry when mpv rolls into the armed track mid-clear.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>