[FFmpeg-devel] [PATCH 1/4] lavc: correctly set AVSubtitle format for text based subtitles.
Wolfram Gloger
wmglo at dent.med.uni-muenchen.de
Mon Dec 31 13:30:57 CET 2012
Hi,
> On Wed, Nov 28, 2012 at 11:37:15AM +0100, Nicolas George wrote:
>> Le septidi 7 frimaire, an CCXXI, Clément Bœsch a écrit :
>> > ---
>> > libavcodec/utils.c | 1 +
>> > 1 file changed, 1 insertion(+)
>>
>> I do not think it can cause any problem, but this AVSubtitle structure is
>> very ugly. So probably ok.
Clément Bœsch <ubitux at gmail.com> writes:
> Finally applied, thanks.
libavcodec/utils.c
ret = avctx->codec->decode(avctx, sub, got_sub_ptr, &tmp);
+ sub->format = sub->num_rects && sub->rects[0]->ass;
Firstly, the AVSubtitle 'format' field appears to be totally unused in
ffmpeg currently, right?
If the intent is to define "format == 1" for text subtitles
rather than 'graphics', please add a comment to avcodec.h to
that effect.
But I think this _will_ cause problems because
(a) I see nothing that forbids a decoder generating graphics and _text_
rectangles in the same AVSubtitle. Why should we forbid that?
(b) If anything, the codec->decode function should set sub->format;
otherwise, how would a completely new decoder set text format?
ASS markup may be good today but I still think it's not the least
common denominator and also it may not be possible for all future
text decoders.
Regards,
Wolfram.
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