[FFmpeg-devel] BUG in use of extradata and extradata_size with dvb subtitles and teletext

[Andriy Lysnevych]

On Sun, Jan 26, 2014 at 3:43 AM, Marton Balint <cus at passwd.hu> wrote:
> I don't think that is acceptable breakage, but others may know this better.
> To make sure things don't break too badly a better solution maybe is to put
> the subtitling_type byte AFTER the composition and ancillary page id, even
> if that is different from the order in the subtitling descriptor.
>
> Also make sure the dvbsub decoder codec still works after your patch, since
> it is using extradata...
>

Indeed dvbsub decoder uses extradata and expects composition_id and
ancillary_id to be the first two values of extradata. Now patches do
not break compatibility:

1) Put subtitling_type byte AFTER the composition and ancillary page
id, as you suggested.
2) DVB subtitles decoder supports both old 4 byte format and new 5
byte (i.e. with subtitling_type) formats

Regards,
Andriy Lysnevych
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