id	summary	reporter	owner	description	type	status	priority	component	version	resolution	keywords	cc	blockedby	blocking	reproduced	analyzed
1924	ASS subtitles are demuxed inconsistently	gjdfgh		"There's a difference how subtitles are demuxed with the ""matroska"" and the ""ass"" demuxers.

Consider an even like this in the source file:
{{{
Dialogue: 0,0:00:00.00,0:00:01.00,,,0000,0000,0000,,text
}}}

""matroska"" outputs as packet:
{{{
0,0,,,0000,0000,0000,,text
}}}

while ""ass"" outputs:
{{{
Dialogue: 0,0:00:00.00,0:00:01.00,,,0000,0000,0000,,text
}}}

Matroska produces output that libass' ass_process_chunk() can consume. That means an application using the ffmpeg demuxer interface to read ASS subtitles (possibly for uniformity with the matroska case) has to add extra workarounds. Further, the ""ass"" output doesn't include the event index, while ""matroska"" does. (The event index is the first number, called ""ReadOrder"" in libass.) Additionally, the ""ass"" output does not seem to seem to set the packet duration correctly.

The ""ass"" decoder in libavcodec is indifferent to that, but libass can't handle it. This makes the ""ass"" demuxer useless. Please fix."	enhancement	closed	normal	avformat	unspecified	invalid	ass				0	0