int avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture, int *got_picture_ptr, const AVPacket *avpkt);
int avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options);
int avcodec_close(AVCodecContext *avctx);
+const char *avcodec_get_name(enum AVCodecID id);
void av_free_packet(AVPacket *pkt);
void av_init_packet(AVPacket *pkt);
int av_dup_packet(AVPacket *pkt);