diff --git a/libavformat/avformat.h b/libavformat/avformat.h index cbd139b574..c540d40dec 100644 --- a/libavformat/avformat.h +++ b/libavformat/avformat.h @@ -145,6 +145,22 @@ * avformat_close_input(). It will free everything associated with the file. * * @section lavf_decoding_read Reading from an opened file + * Reading data from an opened AVFormatContext is done by repeatedly calling + * av_read_frame() on it. Each call, if successful, will return an AVPacket + * containing encoded data for one AVStream, identified by + * AVPacket.stream_index. This packet may be passed straight into the libavcodec + * decoding functions avcodec_decode_video2(), avcodec_decode_audio4() or + * avcodec_decode_subtitle2() if the caller wishes to decode the data. + * + * AVPacket.pts, AVPacket.dts and AVPacket.duration timing information will be + * set if known. They may also be unset (i.e. AV_NOPTS_VALUE for + * pts/dts, 0 for duration) if the stream does not provide them. The timing + * information will be in AVStream.time_base units, i.e. it has to be + * multiplied by the timebase to convert them to seconds. + * + * The packet data belongs to the demuxer and is invalid after the next call to + * av_read_frame(). The user must free the packet with av_free_packet() before + * calling av_read_frame() again or closing the file. * * @section lavf_decoding_seek Seeking * @}