[FFmpeg-devel] [PATCH, v4] lavc/vp9: fix reference frame dimensions check for SINGLE_REFERENCE mode

[Fu, Linjie]

> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of Fu,
> Linjie
> Sent: Friday, March 20, 2020 09:49
> To: Ronald S. Bultje <rsbultje at gmail.com>; FFmpeg development
> discussions and patches <ffmpeg-devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH, v4] lavc/vp9: fix reference frame
> dimensions check for SINGLE_REFERENCE mode
> 
> > From: Ronald S. Bultje <rsbultje at gmail.com>
> > Sent: Thursday, March 19, 2020 20:10
> > To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> > Cc: Fu, Linjie <linjie.fu at intel.com>
> > Subject: Re: [FFmpeg-devel] [PATCH, v4] lavc/vp9: fix reference frame
> dimensions check for SINGLE_REFERENCE mode
> >
> > Hi,
> >
> > On Tue, Mar 17, 2020 at 10:59 AM Linjie Fu
> <linjie.fu at intel.com<mailto:linjie.fu at intel.com>> wrote:
> > With the description in frame size with refs semantics (SPEC 7.2.5),
> > it is a requirement of bitstream conformance that for at least one
> > reference frame has the valid dimensions.
> >
> > Modify the check to make sure the decoder works well in
> SINGLE_REFERENCE
> > mode that not all reference frames have valid dimensions.
> >
> > Check and error out if invalid reference frame is used in inter_recon.
> >
> > One of the failure case is a 480x272 inter frame (SINGLE_REFERENCE mode)
> > with following reference pool:
> >
> > 0.  960x544    LAST    valid
> > 1. 1920x1088 GOLDEN  invalid, but not used in single reference mode
> > 2. 1920x1088 ALTREF  invalid, but not used in single reference mode
> > 3~7  ...     Unused
> >
> > Identical logic in libvpx:
> >
> <https://github.com/webmproject/libvpx/blob/master/vp9/decoder/vp9_d
> ecodeframe.c#L736>
> >
> > Signed-off-by: Linjie Fu <linjie.fu at intel.com<mailto:linjie.fu at intel.com>>
> > ---
> > [v3]: replace assert with check/return, tested in both multi frame/slice
> mode
> > [v4]: clear error_info to make decoding still work for other frames in this
> stream
> >
> > libavcodec/vp9.c      | 20 ++++++++++++++++++--
> > libavcodec/vp9dec.h   |  5 +++++
> > libavcodec/vp9recon.c | 10 ++++++++++
> > 3 files changed, 33 insertions(+), 2 deletions(-)
> >
> > LGTM, thanks for the revisions. (We have been discussing this on IRC.)
> 
> Thanks for the review and valuable suggestions.
> 
Ping for merge, thx.

- Linjie