public static extern int avcodec_encode_subtitle(AVCodecContext* avctx, byte* buf, int buf_size, AVSubtitle* sub);
public static extern void avsubtitle_free(AVSubtitle* sub);
public static extern int avcodec_decode_subtitle2(AVCodecContext* avctx, AVSubtitle* sub, int* got_sub_ptr, AVPacket* avpkt);
public static extern int avcodec_encode_subtitle(AVCodecContext* @avctx, sbyte* @buf, int @buf_size, AVSubtitle* @sub);