[FFmpeg-devel] [PATCH, RFC] lavc/options_table: Add basic candidate h264 profiles

[Fu, Linjie]

> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> lance.lmwang at gmail.com
> Sent: Wednesday, May 6, 2020 22:57
> To: ffmpeg-devel at ffmpeg.org
> Subject: Re: [FFmpeg-devel] [PATCH, RFC] lavc/options_table: Add basic
> candidate h264 profiles
> 
> On Wed, May 06, 2020 at 06:13:10PM +0800, mypopy at gmail.com wrote:
> > On Wed, May 6, 2020 at 6:04 PM mypopy at gmail.com
> <mypopy at gmail.com> wrote:
> > >
> > > On Wed, May 6, 2020 at 5:40 PM Martin Storsjö <martin at martin.st>
> wrote:
> > > >
> > > > On Wed, 6 May 2020, Linjie Fu wrote:
> > > >
> > > > > Allows specifying avctx->profile with string type profile for
> > > > > h264 encoders.
> > > > >
> > > > > Private field/option "profile" may be abled to be removed for basic
> > > > > h264 profiles, directly for encoders like libopenh264/h264_vaapi,
> > > > > or with an map to hardware profile like h264_qsv.
> > > > >
> > > > > Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> > > > > ---
> > > > > One concern is some encoders have options for specific profiles,
> > > > > like "high444p" for nvenc_h264 and "constrained_high" for h264_amf,
> > > > > hence they may not be able to remove the private option easily.
> > > > >
> > > > > Please help to comment.
> > > > >
> > > > > libavcodec/options_table.h | 4 ++++
> > > > > 1 file changed, 4 insertions(+)
> > > >
> > > > This change in itself looks sensible to me (but I'd like for someone else
> > > > to comment as well). Even if it might not be able to get rid of the
> > > > private option for all encoders, it should at least simplify the easiest
> > > > cases.
> > > >
> > > > // Martin
> > > I think we have a discussion about this case,
> > > https://patchwork.ffmpeg.org/project/ffmpeg/patch/fa14da65-9e1a-
> c74b-b3cb-46fc5f3ea932 at gmail.com/
> >
> > I agree with Hendrik Leppkes, and I think "main" more natural than
> > "h264_main"  for 264 codec profile from a user viewpoint, both of
> > command line tools or  application program interface
> 
> So what's the conclusion? I have submit a patch to add mpeg2 profile
>  52 and Marton prefer to use global profile with mpeg2_xxxx. By Hendrik's
> comments, I think it's more reasonable to use private profile.

I'd also prefer an option without prefix which seems more natural, especially
for the codecs that already have implemented it as a private option. Otherwise
it seems to be a sudden break for users to use "h264_main"/"mepg2_main"
instead of "main" unless we declared some deprecated flags and get rid of
the private options later.

Please help to comment.

- Linjie