[FFmpeg-devel] [PATCH 2/2] avcodec: add an AVCodecContext flag to export A53/SCTE20/DVD CC side data on demand

[lance.lmwang at gmail.com]

On Wed, May 11, 2022 at 02:00:10PM +0200, Anton Khirnov wrote:
> Quoting lance.lmwang at gmail.com (2022-05-08 09:17:01)
> > From: Limin Wang <lance.lmwang at gmail.com>
> > 
> > some samples include both A53 and SCTE20 data. Before the commit, both
> > of the will be exported, so the CC data will be repeated or garbarge
> 
> Why would it be garbage? That sounds like a bug.
> Why can't we just export both?
for A53/SCTE20/DVDCC are exprted by A53_CC side data and they're sharing
the same a53_buf_ref to store the data, so if stream contains CC wrapped
as ATSC A53 packets + the same data wrapped as SCTE-20 packets, the CC
data will repeated. We can consider to add a new side data type if necessary,
but it's preferable to export A53_CC even it's SCTE20, so we can't export
both by A53_CC still.

related topic for it:
https://trac.ffmpeg.org/ticket/9724
https://patchwork.ffmpeg.org/project/ffmpeg/patch/20220427084949.73931-1-4rusxg@gmail.com/
https://patchwork.ffmpeg.org/project/ffmpeg/patch/20180306222512.20124-1-ffmpeg@tmm1.net/


> 
> -- 
> Anton Khirnov

-- 
Thanks,
Limin Wang