static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref) { PixdescTestContext *priv = inlink->dst->priv; AVFilterLink *outlink = inlink->dst->outputs[0]; AVFilterBufferRef *outpicref; int i; outlink->out_buf = avfilter_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h); outpicref = outlink->out_buf; avfilter_copy_buffer_ref_props(outpicref, picref); for (i = 0; i < 4; i++) { int h = outlink->h; h = i == 1 || i == 2 ? h>>priv->pix_desc->log2_chroma_h : h; if (outpicref->data[i]) { uint8_t *data = outpicref->data[i] + (outpicref->linesize[i] > 0 ? 0 : outpicref->linesize[i] * (h-1)); memset(data, 0, FFABS(outpicref->linesize[i]) * h); } } /* copy palette */ if (priv->pix_desc->flags & PIX_FMT_PAL) memcpy(outpicref->data[1], outpicref->data[1], 256*4); avfilter_start_frame(outlink, avfilter_ref_buffer(outpicref, ~0)); }