williamconley wrote:Soft phones can have g729 embedded. Most hardware VOIP phones have it installed by default. I don't know of any that have OPUS.
Both sides of the tunnel must have the codec for it to work.
GSM, however, is already in almost every VOIP device during a stock install and uses much less bandwidth than ULAW/G711. G729 uses even less bandwidth and is widely accepted in most devices, but costs money up until recently. Not sure if any softphones have g729 free yet, or OPUS. I'd let that be my guide if I were you (find out), but start with GSM as it's less CPU intense and already installed everywhere.
Please note that the codec you use with your agents is in NO way related to the codec you use with your carriers. Some people forget that too easily.
Thanks for the response.
As I have said before, the remote agents use desktops with chrome (webrtc/viciphone) as their endpoint. So whatever codec can run on chrome is what we can use. I am not sure if g729 will work on chrome.
I want to know the ranking for codecs in terms of the quality of the audio achievable on a poor and relatively latent connection between the asterisk cluster and agent endpoint.
I have just tested opus yesterday, even in wideband it kept below 50kbps. I want to try it in narrowband where the bandwidth goes down to just 16-24 kpbs at g711 quality....Where can I put config for opus as I have tried /etc/asterisk/codecs.conf but asterisk doesn't seem to be picking the configuration for opus from there.
Which codec is better to use in chrome/webrtc environment over low bandwidth (100-200kbps) network with 150ms latency to server?
Opus (only tested wideband, couldn't configure narrowband)
G729 (ok quality, worse than working g711, low bandwidth usage, same cpu usage as opus on poorer audio quality)
GSM (jittery, water sounds, quality poor)
G711 (is not able to cope, I have already tested it.)
The cluster has servers that have dual e5-2620 v3 processors. Generally the load is below 30%....Opus adds about 2-5% extra load which about the same as g729 for 30 endpoints.
I think if I am able to get narrowband setup on opus we might be able to get better output.