marsbewohner Posted June 22, 2011 Report Share Posted June 22, 2011 Hi, is it possible to measure the quality of the MoH sound? We're experiencing that the MoH sound is accompanied by a very disturbing noise when played by the PBX, if you open the file (default SnomOne moh.wav) with Windows Media Player for example everything is fine. CPU or media load can't be the reason, the CPU is bored at 5%. Could it be some kind of codec issue? Quote Link to comment Share on other sites More sharing options...
Vodia PBX Posted June 22, 2011 Report Share Posted June 22, 2011 Is that a file that came with the audio files for the PBX or did you create it on your own? The PBX understands only a narrow subset of the WAV file capabilities, for example it will not take stereo files and the sampling frequency must be 8 kHz. Quote Link to comment Share on other sites More sharing options...
marsbewohner Posted June 22, 2011 Author Report Share Posted June 22, 2011 We're using the default one, and it really sounds like beeing send from Earth to Moon and back + having a darth vader scrambler in between Quote Link to comment Share on other sites More sharing options...
marsbewohner Posted July 12, 2011 Author Report Share Posted July 12, 2011 I want to bring this up again, anything more we could check here? Quote Link to comment Share on other sites More sharing options...
Vodia PBX Posted July 13, 2011 Report Share Posted July 13, 2011 Between mars and earth? Usually when the sound does not sound like packet loss, it is a problem with excessive transcoding. Remember from information theory, transcoding can only reduce the audio quality, even when transcoding "to" a great codec. If you do that a couple of times, it really sounds like smoke signs on a mointain. Least common denominator! Quote Link to comment Share on other sites More sharing options...
marsbewohner Posted July 13, 2011 Author Report Share Posted July 13, 2011 Maybe, if necessary Transcoding might be a reason, but it also sounds like this when having MoH internally. Although I must admit that it's much more worse when you're calling from/to external, no matter if it's landline or mobile. Will do some tests on this... As a question, we're using Asterisk as internal SIP registrar for Sangoma cards which are connected to T1s, the trunk PBX <-> Asterisk should be G711, but in case the outgoing line operates in a lower codec, will the Asterisk handle the transcoding or the SnomOne itself? Quote Link to comment Share on other sites More sharing options...
Vodia PBX Posted July 14, 2011 Report Share Posted July 14, 2011 Asterisk can do transcoding as well. It all depends on the setup. But this could be another transcoding step. IMHO the easiest is to keep it to G711 by default, then the transcoding to the PSTN (PRI, ISDN) can be loss less. Quote Link to comment Share on other sites More sharing options...
marsbewohner Posted July 14, 2011 Author Report Share Posted July 14, 2011 Ok, we're currently investigating on this. Are the default MoH wave files which are delivered with SnomOne in u- or a-law encoded? Quote Link to comment Share on other sites More sharing options...
Vodia PBX Posted July 14, 2011 Report Share Posted July 14, 2011 Are the default MoH wave files which are delivered with SnomOne in u- or a-law encoded? Neither. They are 16 bit/sample. Quote Link to comment Share on other sites More sharing options...
marsbewohner Posted July 14, 2011 Author Report Share Posted July 14, 2011 Ok, our Asterisk is configured to use a-law as default, I'll experiment a little bit with that... Quote Link to comment Share on other sites More sharing options...
Scootr923 Posted March 27, 2013 Report Share Posted March 27, 2013 I am having the same issue. I have been able to narrow it down to be that the call has to be with a cell phone. I do not think that packet loss is an issue(MOS on cal is 4.7). We are using g.729 as our default codec and g.711 as the second choice. Can you suggest the .wav format to use to try and correct this. Quote Link to comment Share on other sites More sharing options...
Vodia PBX Posted March 28, 2013 Report Share Posted March 28, 2013 G.729A is not good with music. Nothing will change that. My recommendation is to keep the volume as low as possible; everything else will be painful. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.