[10.7] Transparent Subtitles

[TheNamelessWonderer]

Describe The Bug
Some subtitles are transparent in 10.7 making them hard to read.

Steps To Reproduce

1. Play a video
2. Watch as some subtitles are transparent

Expected Behavior

The Sub titles shouldn't be transparent

Logs
10:6 FFMPEG command: ffmpeg -ss 00:01:39.000 -noaccurate_seek -f matroska,webm -i file:"/path/to/file" -map_metadata -1 -map_chapters -1 -threads 0 -map 0:0 -map 0:1 -codec:v:0 libx264 -pix_fmt yuv420p -preset veryfast -crf 23 -maxrate 7834386 -bufsize 15668772 -profile:v high -level 4.1 -x264opts:0 subme=0:me_range=4:rc_lookahead=10:me=dia:no_chroma_me:8x8dct=0:partitions=none -force_key_frames:0 "expr:gte(t,99+n_forced*3)" -g 72 -keyint_min 72 -sc_threshold 0 -vf "scale=trunc(min(max(iw\,ih*dar)\,1920)/2)*2:trunc(ow/dar/2)*2,subtitles='/Volumes/sda1/TV Shows/Jojo'\\\''s Bizarre Adventure/Season 3/[Some-Stuffs]_Jojo'\\\''s_Bizarre_Adventure_Diamond_is_Unbreakable_27_(1920x1080_Blu-Ray_FLAC)_[8B33D737].mkv:si=0'" -start_at_zero -vsync -1 -codec:a:0 libmp3lame -ac 2 -ab 192000 -copyts -avoid_negative_ts disabled -f hls -max_delay 5000000 -hls_time 3 -individual_header_trailer 0 -hls_segment_type mpegts -start_number 33 -hls_segment_filename "/Users/user/.local/share/jellyfin/transcodes/f5f139122bdf44f778c29c36b4d383a8%d.ts" -hls_playlist_type vod -hls_list_size 0 -y "/Users/user/.local/share/jellyfin/transcodes/f5f139122bdf44f778c29c36b4d383a8.m3u8"

10.7 FFMPEG command: ffmpeg -f matroska,webm -i file:"/path/to/file" -map_metadata -1 -map_chapters -1 -threads 0 -map 0:0 -map 0:1 -map -0:s -codec:v:0 libx264 -pix_fmt yuv420p -preset veryfast -crf 23 -maxrate 7834386 -bufsize 15668772 -profile:v:0 high -level 41 -x264opts:0 subme=0:me_range=4:rc_lookahead=10:me=dia:no_chroma_me:8x8dct=0:partitions=none -force_key_frames:0 "expr:gte(t,0+n_forced_3)" -vf "scale=trunc(min(max(iw,ih_dar),min(1920,1080*dar))/2)*2:trunc(min(max(iw/dar,ih),min(1920/dar,1080))/2)*2" -start_at_zero -vsync -1 -codec:a:0 aac -ac 2 -ab 384000 -copyts -avoid_negative_ts disabled -max_muxing_queue_size 2048 -f hls -max_delay 5000000 -hls_time 3 -hls_segment_type mpegts -start_number 0 -hls_segment_filename "/Users/user/.local/share/jellyfin/transcodes/429f96bb402453d5392e3e7e80aac2a6%d.ts" -hls_playlist_type vod -hls_list_size 0 -y "/Users/user/.local/share/jellyfin/transcodes/429f96bb402453d5392e3e7e80aac2a6.m3u8"

Screenshots

System (please complete the following information):

• Platform: Linux and iPad
• Browser: Firefox and Jellyfin Mobile App
• Jellyfin Version: 10.7-RC2

Additional Context
This didn't happen in 10.6 and also it is only with certain subtitles and fonts. In this anime the issue only occurs during the intro where the subs are different to the rest of the episode.

[nyanmisaka]

10.6 ass/ssa subtitle burn-in by ffmpeg

10.7 ass/ssa rendered by JavascriptSubtitlesOctopus in browser

[TheNamelessWonderer]

I see is this an upstream issue then?

[nyanmisaka]

I also encountered similar problems on some subtitles before.
JavascriptSubtitlesOctopus may display incorrect transparency for some subtitles.
You can try adding a custom font in dashboard->playback to see if it helps.

[TheNamelessWonderer]

Just to confirm that is a JavascriptSubtitlesOctopus issue here is the same video in VLC with the fonts rending correctly.

[TheNamelessWonderer]

Do you have some fonts I could use or know where I could get some?

[nyanmisaka]

May be Google fonts?
https://fonts.google.com

[TheNamelessWonderer]

I downloaded https://fonts.google.com/specimen/Roboto regular. Made a new folder and extracted them into the folder, put that path into Jellyfin and enabled fallback fonts. Unfortunately it doesn't seem to have done anything and the problem still persists.

[nyanmisaka]

Seems there are some issues with alpha channel.
libass/JavascriptSubtitlesOctopus@aef6772
libass/JavascriptSubtitlesOctopus@3009691

[TheNamelessWonderer]

I see. Both of them are fixes that are merged are they included in 10.7-RC2?

[nyanmisaka]

Sure. But I have never seen it enabled in web browsers.
https://github.com/jellyfin/JavascriptSubtitlesOctopus/blob/58e9a3f1a7f7883556ee002545f445a430120639/src/subtitles-octopus.js#L183

[TheNamelessWonderer]

Nope nothing about it being enabled in my browser console.

[nyanmisaka]

You can force enable it here and rebuild jellyfin-web with it to test.
https://github.com/jellyfin/JavascriptSubtitlesOctopus/blob/58e9a3f1a7f7883556ee002545f445a430120639/src/subtitles-octopus.js#L460

jellyfin-web/yarn.lock

Line 4836 in 3bd4b99

resolved "https://github.com/jellyfin/JavascriptSubtitlesOctopus#58e9a3f1a7f7883556ee002545f445a430120639"

[TheNamelessWonderer]

How do I enable it? What do I need to replace?

[stale]

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[TheNamelessWonderer]

This bug isn’t fixed and still happens in 10.7.5.

[stale]

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[TheNamelessWonderer]

Still an issue on 10.7.7.

[dmitrylyzo]

@TheNamelessWonderer Is there a \fad (fading) in the lines that semi-transparent?

[TheNamelessWonderer]

Do you mean on screen? On screen they show normally but just transparent as shown in the screenshot in the first post. If you mean in the browser console I haven’t looked their but I can have a look if it would help.

Or do you mean in the sub file itself?

[dmitrylyzo]

In the subtitles file.

[TheNamelessWonderer]

Yes there is:

Dialogue: 0,0:02:01.30,0:02:07.10,Part 4 OP3 English,,0,0,0,,{\fad(100,100)}{\1c&H09FFD6&}Shining {\1c&HD055E6&}justice {\1c&H09FFD6&}takes bloom
Dialogue: 0,0:02:07.10,0:02:12.73,Part 4 OP3 English,,0,0,0,,{\fad(100,100)}{\1c&H09FFD6&}Brand-new {\1c&HE5FC3B&}bed town {\1c&H09FFD6&}feels like a breath of fresh air
Dialogue: 0,0:02:12.73,0:02:18.40,Part 4 OP3 English,,0,0,0,,{\fad(100,100)}{\1c&HD500E0&}The cape creates a salty breeze, through the tunnel past the tower's beams
Dialogue: 0,0:02:18.40,0:02:23.66,Part 4 OP3 English,,0,0,0,,{\fad(100,100)}{\1c&HE0ECFF&}Until it's finally drawn in and fades into the town's streets
Dialogue: 0,0:02:23.66,0:02:26.83,Part 4 OP3 English,,0,0,0,,{\fad(100,100)}{\1c&H3100D5&}Within our hearts (Within our hearts)
Dialogue: 0,0:02:26.83,0:02:31.00,Part 4 OP3 English,,0,0,0,,{\fad(100,100)}{\1c&HA200D6&}Lurks a hidden shadow

[l4kr]

I have also noticed ASS/SSA subtitles with motion tracking and/or any sort or special effects to be just static.

I suspect this is a related issue. If not, I will create a new issue.

[dmitrylyzo]

@l4kr
If you post sample events that don't work as expected, I can tell more. But I think this is due to heavy animation, which stalls the oneshot render.

I am waiting for libass/JavascriptSubtitlesOctopus#111 to be merged (we want to migrate to the upstream) and counted about 5 PRs that I am going to open (libass/JavascriptSubtitlesOctopus#111 (comment)). One of them should help a bit with heavy animation - it will discard some frames if it can't render in time.

A new rendering mode from another contributor is also expected - using hardware acceleration in the worker.

[TheNamelessWonderer]

Hello is there any progress on this? I see your pull request on the repo was closed. Also is jellyfin/JavascriptSubtitlesOctopus#21 planning to make it into 10.8? Thanks!

[dmitrylyzo]

Fixed by #3644

[TheNamelessWonderer]

Thank you so much!