1 files changed, 26 insertions, 14 deletions

diff --git a/libavcodec/libpostproc/postprocess.c b/libavcodec/libpostproc/postprocess.c
index bc14ef3828..ba4dd83a14 100644
--- a/libavcodec/libpostproc/postprocess.c
+++ b/libavcodec/libpostproc/postprocess.c
@@ -1051,18 +1051,20 @@ void  pp_postprocess(uint8_t * src[3], int srcStride[3],
 	int mbHeight= (height+15)>>4;
 	PPMode *mode = (PPMode*)vm;
 	PPContext *c = (PPContext*)vc;
-        int minStride= MAX(srcStride[0], dstStride[0]);
+	int minStride= MAX(ABS(srcStride[0]), ABS(dstStride[0]));
+	int absQPStride = ABS(QPStride);
 
-	if(c->stride < minStride || c->qpStride < QPStride)
+	// c->stride and c->QPStride are always positive
+	if(c->stride < minStride || c->qpStride < absQPStride)
 		reallocBuffers(c, width, height, 
 				MAX(minStride, c->stride), 
-				MAX(c->qpStride, QPStride));
+				MAX(c->qpStride, absQPStride));
 
 	if(QP_store==NULL || (mode->lumMode & FORCE_QUANT)) 
 	{
 		int i;
 		QP_store= c->forcedQPTable;
-		QPStride= 0;
+		absQPStride = QPStride = 0;
 		if(mode->lumMode & FORCE_QUANT)
 			for(i=0; i<mbWidth; i++) QP_store[i]= mode->forcedQuant;
 		else
@@ -1072,7 +1074,7 @@ void  pp_postprocess(uint8_t * src[3], int srcStride[3],
 
 	if(pict_type & PP_PICT_TYPE_QP2){
 		int i;
-		const int count= mbHeight * QPStride;
+		const int count= mbHeight * absQPStride;
 		for(i=0; i<(count>>2); i++){
 			((uint32_t*)c->stdQPTable)[i] = (((uint32_t*)QP_store)[i]>>1) & 0x7F7F7F7F;
 		}
@@ -1080,6 +1082,7 @@ void  pp_postprocess(uint8_t * src[3], int srcStride[3],
 			c->stdQPTable[i] = QP_store[i]>>1;
 		}
                 QP_store= c->stdQPTable;
+		QPStride= absQPStride;		
 	}
 
 if(0){
@@ -1095,13 +1098,22 @@ for(y=0; y<mbHeight; y++){
 
 	if((pict_type&7)!=3)
 	{
-		int i;
-		const int count= mbHeight * QPStride;
-		for(i=0; i<(count>>2); i++){
-			((uint32_t*)c->nonBQPTable)[i] = ((uint32_t*)QP_store)[i] & 0x3F3F3F3F;
-		}
-		for(i<<=2; i<count; i++){
-			c->nonBQPTable[i] = QP_store[i] & 0x3F;
+		if (QPStride >= 0) {
+			int i;
+			const int count= mbHeight * QPStride;
+			for(i=0; i<(count>>2); i++){
+				((uint32_t*)c->nonBQPTable)[i] = ((uint32_t*)QP_store)[i] & 0x3F3F3F3F;
+			}
+			for(i<<=2; i<count; i++){
+				c->nonBQPTable[i] = QP_store[i] & 0x3F;
+			}
+		} else {
+			int i,j;
+			for(i=0; i<mbHeight; i++) {
+		    		for(j=0; j<absQPStride; j++) {
+					c->nonBQPTable[i*absQPStride+j] = QP_store[i*QPStride+j] & 0x3F;
+				}
+			}
 		}
 	}
 
@@ -1125,8 +1137,8 @@ for(y=0; y<mbHeight; y++){
 	}
 	else if(srcStride[1] == dstStride[1] && srcStride[2] == dstStride[2])
 	{
-		memcpy(dst[1], src[1], srcStride[1]*height);
-		memcpy(dst[2], src[2], srcStride[2]*height);
+		linecpy(dst[1], src[1], height, srcStride[1]);
+		linecpy(dst[2], src[2], height, srcStride[2]);
 	}
 	else
 	{