[FFmpeg-devel] [PATCH] lavc/vp9: fix reference frame dimensions check

[Fu, Linjie]

> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> Carl Eugen Hoyos
> Sent: Wednesday, March 11, 2020 18:48
> To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH] lavc/vp9: fix reference frame
> dimensions check
> 
> Am Mi., 11. März 2020 um 11:44 Uhr schrieb Linjie Fu <linjie.fu at intel.com>:
> >
> > 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 the condition
> > that not all references frames have valid dimensions.
> >
> > Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> > ---
> > Fix the the decoding faiure for frames with dimension-ilegal refs.
> > Verifying with native vp9 and libvpx-vp9 decoder, the md5 result matches.
> >
> https://github.com/webmproject/libvpx/blob/master/vp9/decoder/vp9_de
> codeframe.c#L1580
> 
> Did you provide a sample?
> 
I'd like to, but to be honest, it seems kind of hard to produce such a stream available
for public (compared with setting TU depth for one frame), hence I could not promise
but will try. (any hints for this?)

To elaborate more, one of the failure case is a 480x272 inter frame with two refs:
Ref[0]: 1920x1088 key frame, invalid;
Ref[1]:  960x 544 inter frame, valid;

Which reports:
[vp9 @ 0x55b18d9be280] Invalid ref frame dimensions 1920x1088 for frame size 480x272

- Linjie