convert ass subtitle contains more than one language to vtt fail

[Tony]

cat /tmp/Armageddon.1998.ass

Title: CNXP
Original Script: lzqc
PlayResX: 384
PlayResY: 288
Timer: 100.0000

[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: chs,simhei,20,&H00ffffff,&H0000ffff,&H00000000,&H80000000,1,0,0,0,90,90,0,0.00,1,2,2,2,20,20,17,1

[V4 Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, TertiaryColour, BackColour, Bold, Italic, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, AlphaLevel, Encoding
Style: eng,Arial Narrow,12,&H00ffeedd,&H00ffc286,&H00000000,&H80000000,-1,0,1,1,0,2,20,20,4,0,1

[Events]
Format: Marked, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:53.11,0:00:55.23,*eng,,0000,0000,0000,,This is the Earth at a time...
Dialogue: 0,0:00:55.36,0:01:00.19,*eng,,0000,0000,0000,,when the dinosaurs roamed a lush and fertile planet.
Dialogue: 0,0:01:07.58,0:01:11.03,*eng,,0000,0000,0000,,A piece of rock just six miles wide...
Dialogue: 0,0:00:53.11,0:00:55.23,*chs,,0000,0000,0000,,这是地球
Dialogue: 0,0:00:55.36,0:01:00.19,*chs,,0000,0000,0000,,那是恐龙称霸的时代 万物滋长 欣欣向荣
Dialogue: 0,0:01:07.58,0:01:11.03,*chs,,0000,0000,0000,,一块只有六里宽的石头

reproduct bug

go install github.com/asticode/go-astisub/astisub@latest
astisub convert -i /tmp/Armageddon.1998.ass -o /tmp/out.vtt

it shows
2022/12/13 21:32:07 astisub: style *eng not found while opening /tmp/Armageddon.1998.ass

[Quentin Renard]

How did you come up with this .ass file ? 🤔

Its content is weird :

1. Only eng style is declared
2. In events, styles *eng and *chs are requested but it won't match anything with the leading *

[Tony]

I extract it from a MKV media file via
ffmpeg -hide_banner -loglevel error -y -i /tmp/Armageddon.1998.mkv -copyts -map 0:3 -an -vn -c:s copy /tmp/3.ass

BTW ffmpeg v5.1.2 extract it into WebVTT it works good as expected
ffmpeg -hide_banner -loglevel error -y -i /tmp/Armageddon.1998.mkv -copyts -map 0:3 -an -vn /tmp/3.vtt

both IINA v1.3.1(mpv 0.34.1) and VLC v3.0.17.3 parse the same Armageddon.1998.mkv subtitle stream successfully.

[Quentin Renard]

Could you share the WebVTT generated by ffmpeg ?

[Quentin Renard]

I've pushed a fix on master, could you check this fixes your issue?

Also could you share both ffmpeg's webvtt as well as astisub's webvtt to check the differences?

[Tony]

Could you share the WebVTT generated by ffmpeg ?

its original file too long, here is first 20 lines

head -n 20 /tmp/3.vtt

WEBVTT

00:53.110 --> 00:55.230
This is the Earth at a time...

00:53.110 --> 00:55.230
这是地球

00:55.360 --> 01:00.190
when the dinosaurs roamed a lush and fertile planet.

00:55.360 --> 01:00.190
那是恐龙称霸的时代 万物滋长 欣欣向荣

01:07.580 --> 01:11.030
A piece of rock just six miles wide...

01:07.580 --> 01:11.030
一块只有六里宽的石头

IINA and VLC auto merge and show the same timestamp *eng and *chs lines in view

I've pushed a fix on master, could you check this fixes your issue?

Also could you share both ffmpeg's webvtt as well as astisub's webvtt to check the differences?

nope, it doesn't works.

I think it is a good idea that go-astisub should use above ass and vtt subtitles snippet as test sample, check it in and out data.

[Quentin Renard]

nope, it doesn't works.

What is going wrong?