MP4GetTrackBitRate - Get the average bit rate in bits per second of the
hFile Specifies the mp4 file to which the operation applies.
Specifies the track for which the bit rate is desired.
Upon success, the average bit rate in bits per second of the track.
Upon an error, 0.
MP4GetTrackBitRate returns the average bit rate in bits per second in
the specified track in the mp4 file.
Note: hint tracks will not return their bit rate via this mechanism.