func: static int vda_h264_end_frame(AVCodecContext *avctx)
  {
      H264Context *h                      = avctx->priv_data;
      struct vda_context *vda_ctx         = avctx->hwaccel_context;
      AVFrame *frame                      = &h->cur_pic_ptr->f;
      struct vda_buffer *context;
      AVBufferRef *buffer;
      int status;
      if (!vda_ctx->decoder || !vda_ctx->priv_bitstream)
      status = vda_sync_decode(vda_ctx);
      frame->data[3] = (void*)vda_ctx->cv_buffer;
      if (status)
          av_log(avctx, AV_LOG_ERROR, "Failed to decode frame (%d)\n", status);