[FFmpeg-devel] [PATCH] lavfi/deshake: fix deshake crash issue.

Colin NG colin_ng at hotmail.com
Sat Sep 22 01:52:34 EEST 2018


1) The crash is caused by accessing un-allocated  memory area.
2) You can't compute the contrast outside of search window (by default, rx=ry=16).

________________________________
From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> on behalf of Michael Niedermayer <michael at niedermayer.cc>
Sent: September 21, 2018 3:24 PM
To: FFmpeg development discussions and patches
Subject: Re: [FFmpeg-devel] [PATCH] lavfi/deshake: fix deshake crash issue.

On Thu, Sep 20, 2018 at 10:39:37AM +0800, mypopy at gmail.com wrote:
> On Wed, Sep 19, 2018 at 7:07 PM Michael Niedermayer
> <michael at niedermayer.cc> wrote:
> >
> > On Tue, Sep 18, 2018 at 09:37:29PM +0800, Jun Zhao wrote:
> > > Fixes ticket #7441.
> > >
> > > Signed-off-by: Jun Zhao <mypopydev at gmail.com>
> > > ---
> > >  libavfilter/vf_deshake.c |   12 +++++++-----
> > >  1 files changed, 7 insertions(+), 5 deletions(-)
> >
> > this doesnt look correct
> >
> > the blocks that will be used are not going out of array? so the contrast
> > calculated from them also should not
> >
> Do you mean the correct way is changing the pos calculated from:
> pos = (y - i) * stride + (x - j);  to  pos = (y + i) * stride + (x + j)  ?

Iam not the author of vf_deshake, but whatever aligns the checked blocks
correctly, should be the correct solution

[...]
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