[FFmpeg-devel] [PATCH/RFC] Fix dvbsub framing inconsistencies/add dvbsub bsf

Tomas Härdin tomas.hardin
Wed Oct 20 10:49:43 CEST 2010


On Tue, 2010-10-19 at 20:55 +0200, Reimar D?ffinger wrote:
> On Tue, Oct 19, 2010 at 11:36:55AM +0200, Tomas H?rdin wrote:
> > I finally got around to fixing this. It happens due to
> > compute_pkt_fields() not setting AV_PKT_FLAG_KEY. The simplest and most
> > intuitive solution to this problem IMO is to consider subtitles to be
> > intra-only. I am not aware of any counter case, but please reply if you
> > know of one.
> 
> PGS (BluRay) subtitles it seems (they seem to have update-only commands
> which we do not support it).
> Depending on how you split them DVD subtitles as well, they can have an
> image first and then multiple palette updates to be applied over time.

It seems the dvbsub standard already thought of that:

"To improve random access to DVB subtitling, a page refresh is also
possible. At page refresh all the subtitling data needed to display a
page is provided."

So the parser should probably stay, and be modified to detect such
refreshes (page_state == 1) and set the key frame flag accordingly. I'll
look into that later.

/Tomas
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