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To the developpers: WAV sound should be improved


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The software has seen so many improvements over the years, but we still need need to upload 8 kHz Mono, 16 bit wav files for prompts.


HD audio now is a standard in the SIP world, and I would love our clients to hear prompts that do not sound sound like they come from underground.


Improving sound quality would be a great feature and a much better experience for any calling party.

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It is actually hard to say how this really turns out. Some people might even be confused if the phone system suddenly sounds so natural (really). Most of the calls that run through the PBX end up in the "PSTN", in other words 8 kHz; especially those calls that are considered valuable. Many years ago when we so proud to present G722 we had to find out that most people don't want it.


The new G711 might become OPUS; but it will take some time until it is really mainstream. Next steps must be to start supporting OPUS and make sure that every recording that we have is with 48 kHz. The codec will make sure that the recorded voice will be presented in the best possible quality.

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  • 2 years later...
  • 1 month later...

Having just deployed Vodia internally in place of another software PBX vendor the difference in audio quality for our IVRs and mailbox prompts is awful in comparison. At least 50% of our calls come via other HD enabled PBX's so some movement here wouldn't be lost on low quality PSTN or cellular calls.

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We had G.722 support for a long time. My estimation is that less than 0.01 percent of the calls were using it, even though most phones support it. There are a few things to keep in mind here.

  • First of all, we have to keep in mind that every kind of transcoding reduces quality. Audio quality never goes up, even when using a great codec. If you are on Opus and then the call gets transcoded to G711, it sounds not as good as everybody using G711. That being said, there are very few (no?) SIP trunk providers that offer anything better than G.711.
  • Internal calls may have great quality. The problem is that they are usually not the call generating revenue in businesses. 
  • Most modern HD codecs were written for client devices, meaning that CPU usage is not a big deal. However when you want to have 500 calls going on in the PBX, it is a big deal.
  • It is debatable, but IMHO there is a certain user expectation about how a office phone system should sound like. When IVR sounds narrow band, callers have that warm fuzzy feeling they are talking to their good old (and reliable) phone system.

From a sales point of view, Opus and HD are indeed a great way to wow new customers. That is currently probably the most important point. 

We have added Opus to the development branch, however this needs to be tested first and made sure that it does not cause any harm. We need to change the default priority of the codecs and put HD first. Otherwise nobody will ever experience HD audio on the Vodia PBX. We found only a few Cisco and Polycom models support it today. Its a chicken egg problem obviously, and the PBX should take the first step. 

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