int shift = p->height - avctx->height;
int subsample_h, subsample_v;
- av_pix_fmt_get_chroma_sub_sample(avctx->pix_fmt, &subsample_h, &subsample_v);
+ av_pix_fmt_get_chroma_sub_sample(p->format, &subsample_h, &subsample_v);
p->data[0] += p->linesize[0] * shift;
if (p->data[2]) {