[FFmpeg-devel] [PATCH] Bluray Subtitle Support, v7 (Updated patch to v12)

Reimar Döffinger Reimar.Doeffinger
Wed Aug 26 20:48:02 CEST 2009

On Wed, Aug 26, 2009 at 08:02:45PM +0200, Michael Niedermayer wrote:
> fine, so i have a few more questions
> * is 0/0 actually required by spec / players or just like the existing
>   muxers do?

I have no spec and I have no player - testing by others is welcome.

> * are the 0 packets we write causing actual problems with spec/players?

They are causing a massive size increase with the current time base
(8*90000 bytes per second) and even with the correct time base for 1 ms
it would still be 8 kB/s

> the internal timebase should be set to whichever value the timebase of
> the subs has (ms ?)

Yes, that can be done in the stream creation logic, but first the AVI
demuxer must be stopped from overwriting it with bogus codec values.

> forcing the written timebase to 0/0 if we do have to do that, is easy
> (obvious if(XSUB) put(0) ..), i dont think ff_parse_specific_params()
> could set a 0/0 tb and the muxer would still function but if it works
> that would be an option as well

ff_parse_specific_params already sets it to 0/1 and it works really
badly or without extra hacks actually crashes, so no I don't think
that's the way to go.

> the demuxer of course will require code to handle this (i think we dont
> have any ATM), that is probably if(XSUB) pts=dts=AV_NOPTS_VALUE and leaving
> it to a parser to fill them in

That is rather independent though IMO, since we have that issue already
with the original .divx files.
Also that will break transcoding, resulting in the message "Subtitle
packets must have a pts", despite the fact that all the necessary info
is there after decoding.

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