[FFmpeg-devel] [PATCH] Add A53 Closed Captions to MPEG header if they are available.

[Devin Heitmueller]

Hello Marton,

On Tue, Jun 6, 2017 at 5:45 PM, Marton Balint <cus at passwd.hu> wrote:

> As far as I remember multiple side data of the same type is not something we
> wanted to support. Why do you need it? Can't a single AV_FRAME_DATA_A53_CC
> side data packet contain many CC entries?

Could you please expand on where this was discussed?  Is there any
design documentation for side data infrastructure that's been
introduced into ffmpeg?  Is there some list of other known design
constraints/limitations?

While I agree it would be great to simply say that you should never
have multiple side data items of the same type, I'm not sure how
realistic that is.  It would be helpful if I could better understand
the rationale in that thinking.

I'm starting a rather large project which will likely stretch the
design for side data in order to support a variety of other ancillary
data protocols (e.g. SCTE-104, SMPTE 2038, etc), and it would be great
to better understand where the constraints are (so I can either plan
to address those issues, or if too significant then choose a different
multimedia framework to work with before making a significant
investment building out a bunch of features in ffmpeg).

Thanks,

Devin

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com