[FFmpeg-devel] [PATCH, v3] 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
> Carl Eugen Hoyos
> Sent: Tuesday, March 17, 2020 23:04
> To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH, v3] lavc/vp9: fix reference frame
> dimensions check for SINGLE_REFERENCE mode
> 
> Am Di., 17. März 2020 um 10:45 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
> SINGLE_REFERENCE
> > mode that not all reference frames have valid dimensions.
> >
> > Check and error out if invalid reference frame is used in inter_recon.
> 
> I strongly suspect we only want to error out if explode > default.
> 
> Not necessarily related to this patch:
> In general, FFmpeg should not unnecessarily copy the behaviour
> of other libraries.

Yes, and IMHO it depends on whether such behavior it's valuable and
suitable for FFmpeg.

(In this case, libvpx uses longjmp to error out when block-level error happens,
which seems not suitable/allowed in FFmpeg)

Thanks for the review.

- Linjie