On Sat, Jan 18, 2025 at 4:18 AM Frank Plowman <p...@frankplowman.com> wrote:
> When the chroma format changes mid-sequence, c->pix_fmt and s->pix_fmt > can get out-of-sync. More specifically, > 1. export_frame_params is called. > c->pix_fmt and s->pix_fmt are both set to their new values. > 2. set_output_format is called. > c->pix_fmt is set back to its old value. > > The two getting out of sync results in a memory error. The check in > export_frame_params passes as it only tests the s->pix_fmt, therefore > c->pix_fmt keeps the old value and the buffers are not allocated for the > new pixel format. > > Patch fixes this by not setting c->pix_fmt in set_output_format. > > Signed-off-by: Frank Plowman <p...@frankplowman.com> > --- > @Nuo Mi, Fei Wang: > Does this look okay? I am not really sure why c->pix_fmt was set again > in set_output_format, was this accounting for some specific scenario? > In terms of bitstreams where the pix_fmt changes, I only have fuzzed > bitstreams unfortunately, so while this prevents crashing it is > difficult to know whether the output is correct. > Hi Frank, I agree with you; it's better to remove the duplicate pix_fmt in the VVC context. If we need it for hardware, it should be renamed to hw_fmt or something more descriptive. Could you share the clip? > --- > libavcodec/vvc/dec.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/libavcodec/vvc/dec.c b/libavcodec/vvc/dec.c > index 1cb168de7e..53e3eeec6d 100644 > --- a/libavcodec/vvc/dec.c > +++ b/libavcodec/vvc/dec.c > @@ -970,7 +970,6 @@ static int set_output_format(const VVCContext *s, > const AVFrame *output) > if ((ret = ff_set_dimensions(c, output->width, output->height)) < > 0) > return ret; > } > - c->pix_fmt = output->format; > return 0; > } > > -- > 2.47.0 > > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
