[FFmpeg-devel] [PATCH 1/3] lavc/avcodec: Add caps for the support of variable dimension encoding

[Fu, Linjie]

> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> Lynne
> Sent: Thursday, June 18, 2020 16:04
> To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH 1/3] lavc/avcodec: Add caps for the
> support of variable dimension encoding
> 
> Jun 18, 2020, 04:02 by linjie.fu at intel.com:
> 
> >> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> Fu,
> >> Linjie
> >> Sent: Tuesday, June 9, 2020 17:02
> >> To: FFmpeg development discussions and patches <ffmpeg-
> >> devel at ffmpeg.org>
> >> Subject: Re: [FFmpeg-devel] [PATCH 1/3] lavc/avcodec: Add caps for the
> >> support of variable dimension encoding
> >>
> >> > From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf
> Of
> >> > Linjie Fu
> >> > Sent: Monday, June 8, 2020 23:11
> >> > To: FFmpeg development discussions and patches <ffmpeg-
> >> > devel at ffmpeg.org>
> >> > Subject: Re: [FFmpeg-devel] [PATCH 1/3] lavc/avcodec: Add caps for the
> >> > support of variable dimension encoding
> >> >
> >> > > From: "Anton Khirnov" <anton at khirnov.net>
> >> > > Sent Time: 2020-06-08 18:50:43 (Monday)
> >> > > To: "FFmpeg development discussions and patches" <ffmpeg-
> >> > devel at ffmpeg.org>
> >> > > Cc:
> >> > > Subject: Re: [FFmpeg-devel] [PATCH 1/3] lavc/avcodec: Add caps for
> the
> >> > support	of variable dimension encoding
> >> > >
> >> > > Quoting Linjie Fu (2020-06-08 10:58:03)
> >> > > > And declare AV_CODEC_CAP_VARIABLE_DIMENSIONS for rawvideo
> >> and
> >> > > > wrapped_avframe.
> >> > > >
> >> > > > Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> >> > > > ---
> >> > > >  doc/APIchanges               | 3 +++
> >> > > >  fftools/cmdutils.c           | 2 ++
> >> > > >  libavcodec/avcodec.h         | 4 +++-
> >> > > >  libavcodec/codec.h           | 5 +++++
> >> > > >  libavcodec/rawenc.c          | 1 +
> >> > > >  libavcodec/version.h         | 2 +-
> >> > > >  libavcodec/wrapped_avframe.c | 1 +
> >> > > >  7 files changed, 16 insertions(+), 2 deletions(-)
> >> > >
> >> > > During the last iteration, I asked how is this preferable to just making
> >> > > a new encoder instance. Don't think I got a sufficient reply.
> >> >
> >> > Thanks Anton for the remind, indeed making a new encoder instance
> >> would
> >> > be
> >> > more general and suitable for all encoders, with resolution changing in
> key
> >> > frames.
> >> >
> >> > In this patch set, I prefer to restrict the implementation/support to
> >> > rawvideo and wrapped_avframe encoders, since they don't need to be
> >> > recreated
> >> > when resolution/dimension changes and are required. at this moment.
> >> >
> >> > Also as we've discussed about whether it's worthwhile:
> >> >
> >> > >> Do we get sufficient benefits from having parameter change
> capability
> >> > inside
> >> > >> encoders over just creating a new encoder instance when needed?
> Do
> >> > people
> >> > >> really need to change resolution mid-GOP?
> >> >
> >> > This implementation didn't touch the logic of encoders which supports
> >> > variable
> >> > resolution encoding on inter frames(vp9, av1), since such
> >> > enhancement/requirement
> >> > seems to be rare for now.
> >>
> >> Sent the encoder instance recreate patch set for review as a follow-up
> step,
> >> please
> >> help to review:
> >> https://patchwork.ffmpeg.org/project/ffmpeg/list/?series=1450
> >>
> >
> > Will apply this patch set (1-3) as discussed in:
> > https://lists.ffmpeg.org/pipermail/ffmpeg-devel/2020-June/264649.html
> >
> 
> You said you'd only apply the first patch, not the entire patchset in your
> previous email.
> I'd like to wait to have a well engineered solution we can agree on instead of
> rushing this in, I too have an interest in variable frame size encoding.

Sure and totally agree, will only apply auto scale patch.
Thanks for the input.

- Linjie