[FFmpeg-devel] [PATCH 3/3] avcodec/wmalosslessdec: Use unsigned operations for overflowing cases

Michael Niedermayer michael at niedermayer.cc
Mon May 16 15:18:00 CEST 2016

On Mon, May 16, 2016 at 02:31:20PM +0200, Paul B Mahol wrote:
> On 5/16/16, Michael Niedermayer <michael at niedermayer.cc> wrote:
> > Fixes undefined behavior in fate-lossless-wma24-2
> >
> > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > ---
> >  libavcodec/lossless_audiodsp.c |    4 ++--
> >  libavcodec/wmalosslessdec.c    |    6 +++---
> >  2 files changed, 5 insertions(+), 5 deletions(-)
> >
> You sure this doesn't introduce artifacts?

It only changes cases that are undefined in C, so before this patch
its certainly wrong as different compilers with different options
will do different things (thats how i found it)

see http://fatebeta.ffmpeg.org/report/x86_64-freebsd10-clang33-ftrapv/20160515224104#failed_tests

If its as intended after the patch i dont know. I hoped somone would
know when seeing the patch, thats why i posted it ...
but fate still passes and all the changed cases are from fate testcases

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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