函数 av_seek_frame 

pub unsafe extern "C" fn av_seek_frame(
    s: *mut AVFormatContext,
    stream_index: c_int,
    timestamp: i64,
    flags: c_int,
) -> c_int

Seek to the keyframe at timestamp. ‘timestamp’ in ‘stream_index’.

@param s media file handle @param stream_index If stream_index is (-1), a default stream is selected, and timestamp is automatically converted from AV_TIME_BASE units to the stream specific time_base. @param timestamp Timestamp in AVStream.time_base units or, if no stream is specified, in AV_TIME_BASE units. @param flags flags which select direction and seeking mode

@return >= 0 on success