swscale: fix underflows in firstline calculations for extreme resizes.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
This commit is contained in:
Ronald S. Bultje 2012-02-22 16:47:14 -08:00
parent 19a65b5be4
commit 491865b57d

View File

@ -407,9 +407,9 @@ static int swScale(SwsContext *c, const uint8_t* src[],
(CONFIG_SWSCALE_ALPHA && alpPixBuf) ? dst[3] + dstStride[3] * dstY : NULL,
};
const int firstLumSrcY= vLumFilterPos[dstY]; //First line needed as input
const int firstLumSrcY2= vLumFilterPos[FFMIN(dstY | ((1<<c->chrDstVSubSample) - 1), dstH-1)];
const int firstChrSrcY= vChrFilterPos[chrDstY]; //First line needed as input
const int firstLumSrcY= FFMAX(1 - vLumFilterSize, vLumFilterPos[dstY]); //First line needed as input
const int firstLumSrcY2= FFMAX(1 - vLumFilterSize, vLumFilterPos[FFMIN(dstY | ((1<<c->chrDstVSubSample) - 1), dstH-1)]);
const int firstChrSrcY= FFMAX(1 - vChrFilterSize, vChrFilterPos[chrDstY]); //First line needed as input
// Last line needed as input
int lastLumSrcY = FFMIN(c->srcH, firstLumSrcY + vLumFilterSize) - 1;