[FFmpeg-devel] [PATCH] ffh264: stop trying to decode colorspaces it doesn't support

Michael Niedermayer michaelni
Tue Jan 11 03:41:03 CET 2011

On Mon, Jan 10, 2011 at 06:02:16PM -0800, Jason Garrett-Glaser wrote:
> On Mon, Jan 10, 2011 at 5:52 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > On Mon, Jan 10, 2011 at 03:30:18PM -0800, Jason Garrett-Glaser wrote:
> >> This works with one problem: I can't get ffh264 to stop trying to
> >> decode. ?It will simply keep spamming and spamming if it encounters an
> >> unsupported file, instead of printing the error once and exiting.
> >
> >> What's the right way to fix this?
> >
> > you have to fail from ?ff_h264_decode_init()
> > but is it really fatal if one SPS has a unsupported chroma_format ?
> > there can be multiple SPS and that one maybe isnt even used in the whole
> > file
> That's so rare that probably no files exist in the world that do that.
> Maybe it's not the "right" thing to do, but I think that ffmpeg should
> not try to decode streams it doesn't support: it just confuses users.
> I also don't think that the H.264 spec lets you switch chroma formats
> randomly between frames, as that would make inter prediction slightly
> problematic...

there could be IDR between
practical case would be 2 films one in 422 one in 420 transmitted on the same
channel one after the other. When crudely cut one still could have the
previous films SPS at the begin
iam not saying this is a prtactical issue but i know mpeg2 switches resolution,
interlacing and other supposedly unchangeable things as well in rare cases in
real world streams
so at least the user should be able to override and force lavc to continue
trying even if it appears unsupported at first

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Avoid a single point of failure, be that a person or equipment.
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