[FFmpeg-devel] [PATCH] new codec id for SSA/ASS subtitles

Aurelien Jacobs aurel
Sat Dec 29 20:32:56 CET 2007

On Sat, 29 Dec 2007 18:42:46 +0300
Evgeniy Stepanov <eugeni.stepanov at gmail.com> wrote:

> Hi,
> current matroska demuxer mangles SSA/ASS subtitles by stripping 8 leading 
> fields from each line in an effort to make them look like plaintext 
> subtitles. I believe that conversion between different formats is not a 
> dexumer's job.

I agree. That was just a simple way to get those subtitles at least
partly working. Right now, MPlayer display them properly as plain text.

> With this patch, SSA/ASS subtitles are kept unchanged. To distinguish them 
> from simple plaintext subtitles, a new codec id is added.

That's something desirable. And I'm willing to apply this patch.
But this will break playback of those subtitles in MPlayer.
Do you plan to improve MPlayer's demux_lavf so that it supports
SSA subtitles ?

Also I gave one more look at SSA specs, and I think we may need
to append the following text to the extradata so that a clean
SSA decoder can decode packets payload without having to guess
fields contents:

Format: ReadOrder, Layer, Style, Name, MarginL, MarginR, MarginV, Effect, Text

At least that's what I deduced from:
Do you agree with this ?


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