In article <[EMAIL PROTECTED]>, xlab <[EMAIL PROTECTED]> wrote: > > > In article <[EMAIL PROTECTED]>, xlab <[EMAIL PROTECTED]> > > wrote: > > > >>When using phones that are using G.711 codec and the calls are recorded > >>with "Monitor", when played back the files sound great. > >> > >>When we use gsm codec at one or both ends of the call, the recorded > >>files sound very bad. Much worse than the audio sounds during the call. > > > >This is probably because Asterisk calls sox to mix the separate incoming > >and outgoing files into a single file. In order to mix two gsm files, > >sox will need internally to convert them both to linear, do the mixing, > >and then convert back to gsm. Since gsm is not a lossless compression, > >the sound gets worse with each conversion round-trip. > > > We have tried it with and without the mixing option. Sox was not used. > The recorded sounds are garbled sounding. There appears to be a 3-4 Hz > signal in the audio that causes the amplitude to decrease momentarily > for around 26ms at that rate.
Oh well, it was just a thought as I read your posting.... > As I stated previously, this only happens when gsm is used on the > phones. It is still present in the recording regardless of the three > ways the recorded file is saved (gsm, wav, WAV). The problem is not the > normal degradation of the gsm codec, it is much worse than that. Any > other ideas? I can send a sample file to listen to if that would help. Sorry, but codecs are outside my area, and lack of time is a problem... Hope you find the solution Cheers Tony -- Tony Mountifield Work: [EMAIL PROTECTED] - http://www.softins.co.uk Play: [EMAIL PROTECTED] - http://tony.mountifield.org _______________________________________________ Asterisk-Users mailing list [email protected] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
