filename = 'YourFileNameGoesHere.mp3';
fid = fopen(filename, 'r');
file_bits = fread(fid, [1 inf], 'bit1=>uint8');
fclose(fid);
file_bits is now a vector of binary values ready for modulation.
At the other end, demodulate into a vector of uint8, and do any appropriate error correction. Then
filename = 'YourOutputFileNameGoesHere.mp3';
outfid = fopen(filename, 'w');
fwrite(outfid, file_bits, 'bit1');
fclose(outfid);
The other end will now have a copy of the mp3 file, which can be played through whatever mp3 player the other end has.
Note: if there was uncorrected transmission noise, then the file that is written might be corrupted in a way that makes it impossible to play. So be sure to put in enough error detection and correction for the circumstances.
