Author Topic: transcoding for dissimilar codec supporting endpoints  (Read 1018 times)

Dieselboy (OP)

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transcoding for dissimilar codec supporting endpoints
« on: June 15, 2017, 06:06:53 AM »
My PSTN SIP trunk is using g.711 but some of my fancy endpoints support Opus. Opus codec is great because it can recover quite well from a bit of lost packets. So those fancy wifi endpoints which have the odd lost packet on the wifi or their remote internet are great on internal calls. But occasionally have some issues when on a PSTN call.

I have the idea that if I invoke a transcoder for PSTN calls, then I can utilise the Opus codec between the device and the voice gateway / transcoder / Cisco CUBE and then from there I can use the g711. My 2921 doesn't support Opus anyway, but has anyone done anything like this before? Is it normally done or can it even be done?

DanC

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Re: transcoding for dissimilar codec supporting endpoints
« Reply #1 on: July 29, 2017, 04:41:17 PM »
Sounds like a good idea in principal, I like Opus, the quality is great between Jabber or deskphones that support it!

However, not sure the CUBE supports it, doesn't seem to appear on the supported codecs list:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube/configuration/cube-book/cube-codec-basic.html#concept_481BE95CF6AB447C9DB4C46866FDA2D5

In our case, for low BW connections, we usually run g.729 to the CUBE, then transcode to g.711 which is the only codec our ITSP supports.


wintermute000

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Re: transcoding for dissimilar codec supporting endpoints
« Reply #2 on: July 29, 2017, 09:11:49 PM »
ilbc is the way to go for CUCM and Cisco handset / DSP transcoder supported WAN friendly codec

Dieselboy (OP)

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Re: transcoding for dissimilar codec supporting endpoints
« Reply #3 on: July 30, 2017, 08:21:42 PM »
We find that g.729 is not great for conferencing, the quality is worstened enough that we find it difficult to understand each other. Most of the people that work in my company don't have English as their first language.  We literally have people from all corners of the globe.

I wonder if the new ISR's will support this.

Dieselboy (OP)

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Re: transcoding for dissimilar codec supporting endpoints
« Reply #4 on: July 30, 2017, 08:23:33 PM »
ilbc is the way to go for CUCM and Cisco handset / DSP transcoder supported WAN friendly codec

Hopefully things are changing. ilbc is good but I've found that Opus is way better in terms of clarity / audio quality and packet loss concealment.