libavcodec/webp: treat out-of-bound palette index as translucent black

See https://code.google.com/p/webp/issues/detail?id=206
for a description of the problem/fix.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

This patch makes the decoder follow the recommendation of the spec.
There is some disagreement (see "[FFmpeg-devel] [PATCH]: libavcodec/webp")
about what would be best to be written in the spec, so in case the spec
is changed again, this potentially would need to be amended or reverted
(cherry picked from commit 4fd21d58a7)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Pascal Massimino 2014-09-16 17:01:07 +02:00 committed by Michael Niedermayer
parent dc4e34a2f0
commit b7f2719951

View File

@ -1028,7 +1028,7 @@ static int apply_color_indexing_transform(WebPContext *s)
ImageContext *img;
ImageContext *pal;
int i, x, y;
uint8_t *p, *pi;
uint8_t *p;
img = &s->image[IMAGE_ROLE_ARGB];
pal = &s->image[IMAGE_ROLE_COLOR_INDEXING];
@ -1066,11 +1066,11 @@ static int apply_color_indexing_transform(WebPContext *s)
p = GET_PIXEL(img->frame, x, y);
i = p[2];
if (i >= pal->frame->width) {
av_log(s->avctx, AV_LOG_ERROR, "invalid palette index %d\n", i);
return AVERROR_INVALIDDATA;
AV_WB32(p, 0xFF000000);
} else {
const uint8_t *pi = GET_PIXEL(pal->frame, i, 0);
AV_COPY32(p, pi);
}
pi = GET_PIXEL(pal->frame, i, 0);
AV_COPY32(p, pi);
}
}