void ff_xvmc_init_block(MpegEncContext *s) { struct xvmc_render_state *render = (struct xvmc_render_state*)s->current_picture.data[2]; assert(render); if (!render || render->magic != AV_XVMC_RENDER_MAGIC) { assert(0); return; // make sure that this is a render packet } s->block = (DCTELEM *)(render->data_blocks + render->next_free_data_block_num * 64); }