+int ff_nvdec_simple_end_frame(AVCodecContext *avctx);
+int ff_nvdec_simple_decode_slice(AVCodecContext *avctx, const uint8_t *buffer,
+ uint32_t size);
+int ff_nvdec_frame_params(AVCodecContext *avctx,
+ AVBufferRef *hw_frames_ctx,
+ int dpb_size);
+int ff_nvdec_get_ref_idx(AVFrame *frame);