Some mpeg versions use LSF (low sampling frequency) when encoding
low sample rates which changes a bit how the side info is layed out.
Also skip trying to separate data and other_data as after reading up
a bit on how main data begin and bit reservoir works i think it was done
incorrectly. To know the real audio data length i think you need to decode
the huffman tables. Instead just have a "audio_data" field which are the
bits with audo data for current and possibly following frames.
