ASS Subtitles not working

[ghost]

Describe the bug

Playing video with embedded ASS subtitles doesn't display any subtitle.

To Reproduce

1. Download mkv anime from this season
2. Let jellyfin server index said anime
3. Play said anime on smartphone

Expected behavior

Subtitle visible when playing video

Logs

No error is displayed whatsoever

Screenshots

Sample video media info

System (please complete the following information):

• App version: v2.0.0-rc2
• Android version: 5
• Device manufacturer and model: Samsung Galaxy S5 Neo
• Jellyfin server version: 10.6.0
• The type of video player implementation used: default player, i think it's the "web" player

Additional context

Only workaround is manually set subtitles to "Off" and the select the subs track again. This sometimes triggers #46

[Maxr1998]

Like for the subtitle desync, I fear this is a web issue again. If I understand it correctly, the subtitles do occasionally show (or if using the workaround), but most times don't?

[ghost]

Like for the subtitle desync, I fear this is a web issue again.

It seems you're right, i just switched to ExoPlayer and i have not been able to reproduce this issue, so it's likely webplayer-only problem.

If I understand it correctly, the subtitles do occasionally show (or if using the workaround), but most times don't?

Exactly.

[redactedscribe]

I couldn't get ASS subtitles to show no matter which subtitle option I selected for a movie: toggling to Off, Sub - Eng, or Undefined (external). This was with the Native player (I presume this is what people mean by ExoPlayer).

However, after numerous attempts, starts and stops etc, the subtitles started working immediately after switching to the Web player and playing it (albeit soon became unusable due to the de-sync bug). After that, I switched back to the Native player and subtitles were still working (and no de-syncing despite a lot of seeking). That was only temporary: If I stopped the Native player playback (returned to menu / home screen) and navigated to hit play on the video again, the subtitles were now gone and no matter the options I selected, they wouldn't come back. (Play method: Transcode and Transcoding: true).

I'm not sure how Jellyfin works, but my guess is the Web player is extracting the subtitles fine, and they remain on-disk after switching to the Native player. But once I stop the Native player, Jellyfin discards the transcoded files, and on pressing play again, the Native player won't extract the subs. Technically, the players aren't the ones doing the extracting I guess, but you get my point, I hope.

Curiously, this seems limited to only when transcoding: playing a different video (a series) via the Native player (Play method: DirectStream and Transcoding: false), the ASS subs are extracted fine and there is no issue (I can turn the subs on and off at will).

---

Media Info (for the transcoded video/movie):

Container: mkv

Video	Audio	Subtitle	Subtitle
Title 1080p HEVC	Title Eng AAC 5.1 Default	Title Sub - Eng	Title Undefined
Codec HEVC	Language eng	Language eng	Codec ASS
Profile Main 10	Codec AAC	Codec ASS	Default No
Level 120	Profile LC	Default No	Forced No
Resolution 1916x1080	Layout 5.1	Forced No	External Yes
Aspect ratio 16:9	Channels 6 ch	External No
Interlaced No	Bitrate 320 kbps
Framerate 23.976025	Sample rate 48000 Hz
Bitrate 1749 kbps	Default Yes
Pixel format yuv420p10le
Ref frames 1

Media Info (for the DirectStream video/series):

Container: mkv

Video	Audio	Subtitle	Subtitle
Title 1080p H264	Title Jpn FLAC stereo Default	Title Sub - Eng - Default	Title Undefined
Codec H264	Language Jpn	Language Eng	Codec ASS
AVC No	Codec FLAC	Codec ASS	Default No
Profile High	Layout Stereo	Default Yes	Forced No
Level 41	Channels 2 ch	Forced No	External Yes
Resolution 1920x1080	Sample rate 48000 Hz	External No
Aspect ratio 16:9	Bit depth 16 bit
Interlaced No	Default Yes
Framerate 23.976025
Bitrate 6532 kbps
Bit depth 8 bit
Pixel format yuv420p
Ref frames 1
NAL 0

---

After some more testing, it seems that this bug is related to the subtitle selection option on the summary screen, the one shown before pressing play on a video (the page with the date, runtime, ratings, etc).

Once I changed the embedded subtitle's Default status to true (using MKVToolNix), the video now plays with subtitles. Granted, re-copying the container may have fixed some errors in the MVK itself, but I don't think that was the case: If you choose to start playing this particular movie with subtitles turned Off (via that prior summary screen), it's impossible to switch the subtitles on when the video is playing. Same goes for if you start this video with a subtitle selected: the subtitles will now work, but it's impossible to turn them off. This, again, is all in the Native player.

Current conclusion seems to be subtitle selection is somehow bugged. If a subtitle track isn't turned on before playing a video (because it wasn't manually selected, or wasn't automatically set due to not being the default), subtitles cannot be displayed for the video.

Something else curious: the subtitles shown for the transcoded movie, seem styled (and not according to the app's subtitle settings as far as I could tell). The DirectStream series however should have some fancy styled subs, but they are all displayed with a black background.

It's hard to pin down exactly what's happening, or what's the cause, but hopefully that wasn't too confusing and may help provide some clues.

Thanks.

[nielsvanvelzen]

Note that ExoPlayer doesn't really support ASS or SSA subtitles, I'd recommend enabling transcoding for those.

[redactedscribe]

That may be why it's a bit buggy then. Are there any plans for it to support SubStation Alpha subs?

I assume you mean to turn off Allow subtitle extraction on the fly? ("Disable this to have embedded subtitles burned in with video transcoding when they are not natively supported by the client device."). That's a solution I guess, but now all content will have burned-in subs I presume.

I could convert the ASS subs to SRT, but that could turn out a mess depending how styled the sub is. I don't know if Jellyfin will already automatically choose an SRT over an ASS/SSA sub when using the Native player, but that may be a good idea (if SRT is supported).

[Artiume]

google/ExoPlayer#8435

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