I tried a few years ago to write an application similar to audio diffmaker. It's open source http://wavm.sf.net There is even an example of a redigitized signal compared to the source .wav file. The application is not complete, but it shows that: - there's noise but it could be from the CD player (an old Sony car discman) or from the on-board A/D converter. - there is a gradual drift over time because I did not have a dynamic realignment where I readjust the alignment over time to account for CD player system clock error and A/D converter clock error.
So there is the key problem: how to do the alignment: a) plain cross correlate only in time domain? This may weight the alignment more towards the larger amplitude low frequencies. b) Pick a few frequncies and monitor the phase between them? c) how to warp the time domains to minimize the error. d) how to cancel out common mode noise (common between the two sources) like 60/50Hz hum. This part can make the error appear to be larger than it is. If you use a single frequency, you may get more clues. ( http://wavb.sf.net is a utility for signle tone .wav files ). And //wava.sf.net does word by word compare between wav files. Audio diff does not appear to be open source, but working with single frequency tones maybe someone can gather some clues. -- kgoulet ------------------------------------------------------------------------ kgoulet's Profile: http://forums.slimdevices.com/member.php?userid=12688 View this thread: http://forums.slimdevices.com/showthread.php?t=37352 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
