[FFmpeg-devel] libavcodec/webp : fix return code check in lossy decoding

[Michael Niedermayer]

On Sat, Jul 09, 2016 at 11:53:04AM +0200, Hendrik Leppkes wrote:
> On Sat, Jul 9, 2016 at 11:13 AM, Michael Niedermayer
> <michael at niedermayer.cc> wrote:
> > On Sun, Jun 26, 2016 at 10:45:33PM +0200, Martin Vignali wrote:
> >> Hello,
> >>
> >> in attach patch to fix ret code check in webp lossy decoding (when files
> >> have alpha)
> >>
> >> before this patch, if an error occured during rgb decoding
> >> the return code was ignored. And a useless ret test was made
> >> after alpha decoding.
> >>
> >> after this patch, the return code of rgb is test before
> >> trying to decode alpha.
> >>
> >>
> >> Comments welcome
> >>
> >> Martin
> >> Jokyo Images
> >
> >>  webp.c |    4 ++--
> >>  1 file changed, 2 insertions(+), 2 deletions(-)
> >> 494399734be14a906e03a1b976dbca27c442cdac  0001-libavcodec-webp-fix-return-code-check-in-lossy-decod.patch
> >> From 4b7a1b3c03ec1a9062d3100d79668d905f6226fe Mon Sep 17 00:00:00 2001
> >> From: Martin Vignali <martin.vignali at gmail.com>
> >> Date: Sun, 26 Jun 2016 22:36:23 +0200
> >> Subject: [PATCH] libavcodec/webp : fix return code check in lossy decoding
> >>
> >> before this patch, if an error occured during rgb decoding
> >> the return code was ignored. And an useless ret test was made
> >> after alpha decoding.
> >>
> >> after this patch, the return code of rgb is test before
> >> trying to decode alpha.
> >
> > should not both be attempted to be decoded and in case both fail an
> > error be returned?
> >
> > One could be correctly decoded and that should not be discarded
> > but maybe iam missing something
> >
> 
> Decoding the alpha plane when the RGB plane failed seems rather
> useless, doesn't it.

I dont know
to me having an alpha plane seems better than having nothing

With slices we generally also return what we can even if its just
one macroblock we could decode
also with videos and slices previous frames would be used to fill in
missing areas ...


> One may argue that decoding and returning the RGB and ignoring failure
> in alpha may be useful.
> 
> - Hendrik
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-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The greatest way to live with honor in this world is to be what we pretend
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