[FFmpeg-devel] [PATCH, v2 3/3] lavc/libvpxenc: add dynamic resolution encode support for libvpx

[Fu, Linjie]

> -----Original Message-----
> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> Of James Zern
> Sent: Thursday, August 1, 2019 07:15
> To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH, v2 3/3] lavc/libvpxenc: add dynamic
> resolution encode support for libvpx
> 
> Hi,
> 
> On Tue, Jul 30, 2019 at 10:06 PM Linjie Fu <linjie.fu at intel.com> wrote:
> > [...]
> > diff --git a/libavcodec/libvpxenc.c b/libavcodec/libvpxenc.c
> > index feb52ea..800ba18 100644
> > --- a/libavcodec/libvpxenc.c
> > +++ b/libavcodec/libvpxenc.c
> > @@ -1067,6 +1067,15 @@ static int vpx_encode(AVCodecContext *avctx,
> AVPacket *pkt,
> >      int res, coded_size;
> >      vpx_enc_frame_flags_t flags = 0;
> >
> > +    if (frame && (avctx->width != frame->width ||
> > +                  avctx->height != frame->height)) {
> > +        avctx->width  = frame->width;
> > +        avctx->height = frame->height;
> > +
> > +        avctx->codec->close(avctx);
> 
> You shouldn't need to destroy the encoder for a resolution change,
> unless I'm missing something. Take a look at resize_test.cc [1].
> 
> [1]
> https://chromium.googlesource.com/webm/libvpx/+/refs/heads/master/te
> st/resize_test.cc#305

Yes, IMHO vp8 supports resolution change in key frame, and for vp9,  resolution change
is supported per frame, thus current modification may lead to unnecessary Key frames.

Will find a better solution. Thanks.

- linjie