[asterisk-dev] OPUS horrible quality with packet loss

[Yury Tsaregorodtsev]

Hi Alexander,
I did try your opus version including native PLC patch (on asterisk 13.14.0, everything compiled without issues but anyway maybe version is too high ?)
I wouldn't see much improvements on quality..... From my personal point of view it's sounds little bit better, from point of view PESQ - predicted MOS its same as without native patch, around 1.025.
If you have time I can setup for you 2x ESXI instances with prepared environment of 2x asterisk with simple configuration and ITU-T PESQ utility, so you can hear everything yourself.

P.S. stupid question, but anyway, will it be a solution to use RTP on TCP if we have high loses/delay spikes ?



> On 3 Apr 2017, at 11:51, Alexander Traud <pabstraud at compuserve.com> wrote:
> 
> With Opus Codec, speech frames interdepend. When one RTP packet is lost, several frames are corrupted. Furthermore, when the RTP packet is not lost but just late, Asterisk simply forwards it down to the transcoding modules. Consequently, a late packet corrupts even more frames. 
> 
> The Opus Codec is able to cope with all this. It is called native packet-loss concealment (Native-PLC). However, Asterisk has to tell the Opus Codec library that there was loss. In RTP, its sequence number can be used for this. More details in <http://issues.asterisk.org/jira/browse/ASTERISK-25629>.
> 
> At <http://github.com/traud/asterisk-opus>, you find a module which uses the PLC of Opus Codec. To enable Asterisk to signal loss/late, you have to apply the <enable_native_plc.patch> there. Please, give it a try and report whether it improves the situation for you.
> 
> When that approach is better, someone (you?) has to drive Native-PLC in Asterisk. Or you sponsor a bug bounty so someone drives Native-PLC into Asterisk on your behalf.
> 
> 
> 
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