On Wed, Feb 18, 2015 at 02:22:53PM -0800, Chris Kennedy wrote: > This is a pretty obvious bug we caught in the thumbnail filter that is very > subtle and hardly ever shows issues except for certain videos. Yet it can > be seen how it is blatantly going out of bounds by basing the width > increment off of i*3 that resulted in odd crashes in rare cases. > > > Thanks, > Chris > -- > --- > Chris Kennedy > Video Engineer > CrunchyRoll - http://www.crunchyroll.com
> diff --git a/libavfilter/vf_thumbnail.c b/libavfilter/vf_thumbnail.c
> index 1883154..a1272a0 100644
> --- a/libavfilter/vf_thumbnail.c
> +++ b/libavfilter/vf_thumbnail.c
> @@ -142,7 +142,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame
> *frame)
>
> // update current frame RGB histogram
> for (j = 0; j < inlink->h; j++) {
> - for (i = 0; i < inlink->w; i++) {
> + // last third of image, walk every 3 bytes/pixels reading RGB
> + for (i = 0; i < inlink->w/3; i++) {
width is expressed in pixels, not bytes.
How to reproduce the issue or crash?
> hist[0*256 + p[i*3 ]]++;
> hist[1*256 + p[i*3 + 1]]++;
> hist[2*256 + p[i*3 + 2]]++;
>
--
Clément B.
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