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

[Lynne]

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.