static AVFilterBufferRef *get_video_buffer(AVFilterLink *link, int perms, int w, int h) { FlipContext *flip = link->dst->priv; int i; AVFilterBufferRef *picref = avfilter_get_video_buffer(link->dst->outputs[0], perms, w, h); for (i = 0; i < 4; i ++) { int vsub = i == 1 || i == 2 ? flip->vsub : 0; if (picref->data[i]) { picref->data[i] += ((h >> vsub)-1) * picref->linesize[i]; picref->linesize[i] = -picref->linesize[i]; } } return picref; }