func: static int planarRgbToplanarRgbWrapper(SwsContext const uint8_t *src[], int int srcSliceY, int uint8_t *dst[], int dstStride[]) if ( dst [ 3 ] )  fillPlane ( dst [ 3 ] , dstStride [ 3 ] , c -> srcW , srcSliceH , srcSliceY , 255 ); static void fillPlane(uint8_t *plane, int stride, int width, int height, int uint8_t val) int i ; uint8_t * ptr = plane + stride * y ; for (i = 0; i < height; i++) memset ( ptr , val , width ); ptr += stride; 