[asterisk-dev] OPUS horrible quality with packet loss

[Kevin Harwell]

On Fri, Mar 31, 2017 at 6:54 PM, Yury Tsaregorodtsev <aero.1080 at icloud.com>
wrote:

> Examples of OPUS with 30% of LOSS with FEC on http://opus-codec.org/
> examples/
> Sounds too perfect. Why I can't achieve even similar quality on asterisk
> with built codec by digium?
> To simulate 30% packet loss I use:
>
>  # tc qdisc add dev eth0 root netem delay 100ms loss 30%
>
> But even with 15-20% of loss it's almost impossible to talk.
> Tried different bitrates, result is always same.
> If I do PESQ predicted MOS of degraded audio (recorded with packet loss)
> in compare to original: 1.025
> Horrible results, horrible sound.
>
> Anyone get better experience using opus with huge packet losses ?
>
>
Have you enabled FEC and made sure both sides negotiated it? If not you can
enable it within "codecs.conf" by setting "fec=yes".

When a packet has been lost and the decoder receives a frame with FEC data
(and fec is enabled) it will attempt to rebuild the lost packet (current
packet minus one) from the given FEC information.


Kevin Harwell
Digium, Inc. | Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at: http://digium.com & http://asterisk.org
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