IP Telephony - VCX
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Poor Audio Quality on MOH after conversion to G729

 
Douglas Gillson
Occasional Advisor

Poor Audio Quality on MOH after conversion to G729

After converting IPM to G729 the canned music on hold is loud and distorted.

 

uploaded a new music .wav file and ran wav2ip but it doesn't sound any better.

 

Is there a recommended application we can use to convert the .wav file directly to the format IPM is looking for for G729 without having to use wav2ip ?

 

Assume I would copy this file to /usr/app/app.dir/speak.vox

3 REPLIES 3
IanTomkins
Advisor

Re: Poor Audio Quality on MOH after conversion to G729

To be honest G729 is very compressed and doesn't deal with music at all well, especially if your call go over any carrier who also compress it resulting in multiple re-encodes.

 

Note that the WAV file that the VCX requires is in a very particular format which most WAV files are not.  You may also need to experiment with reducing the volume of your WAV file before you convert it on the VCX.

 

I have sucessfully used the linux command line tool sox to make the required format change and volume changes in one step as follows:

 

sox input.wav -c 1 -r 8000 -U output.wav vol -17 dB

 

Note that sox is not installed on VCX systems as standard, although it is possible to install centos packages on a VCX system because VCX is built from modified Redhat Enterprise sources.

 

For VCX 7.x use Centos 3.9 and for VCX 8.x to 9.5.x use Centos 4.8 packages.

 

To install sox you would need the sox, libogg and libvorbis rpms.

 

Note that installing third party RPMs on a VCX is not recommended in general.

Justin_Goldberg
Valued Contributor

Re: Poor Audio Quality on MOH after conversion to G729

Sorry for taking over this thread, but is it possible to use an external source music player like an MOH box or ipod for music on hold on the VCX?
wkmiller
New Member

Re: Poor Audio Quality on MOH after conversion to G729

I tried many variations on formating the audio files with the G729 and VCX framework. Nothing would work due to the high compression as already mentioned. So we just had our carrier (ATT) drop the G729 and used G711 only. Much better.