Read packets of a media file to get stream information. This is useful for file formats with no headers such as MPEG. This function also computes the real frame rate in case of mpeg2 repeat frame mode.
The logical file position is not changed by this function; examined packets may be buffered for later processing.
int av_find_stream_info(AVFormatContext *ic);
A pointer to an AVFormatContext struct. Media file handle.