Codecs FreePBX: Opus, AAC, Vorbis

FreePBX
1

Hi! I found out this (not so recent) article on how the Codecs are evolving. https://bloggeek.me/opus-hd-voice-domination/

  1. FreePBX already uses Opus. AAC and Vorbis have a future in the codecs field?

  2. Also, I am using the following codecs in my FreePBX, in this sequence: opus, g719, ulaw, alaw, gsm, g726, g723, g722, g729. I wonder if I need all those codecs and do not know if their sequence into the FreePBX trunk will reduce call completion time or call quality.

any advice and comment is welcome! :slight_smile:

2

Yes, Opus has been added to FreePBX only recently. What triggered it is the change in position from Digium, before they would not include Opus code in asterisk because they were afraid of copyright issues. Now they changed their stance and Opus is present in asterisk starting from 13.11+ and 14.0.1 if I am not mistaken.
I am quite excited with Opus, it has the potential to be the one codec to rule them all. Unfortunately a world where you will only have Opus enabled is unlikely anytime soon given POTS and legacy equipment.

Answering your questions:

  1. I do not think AAC and Vorbis make sense, first because Opus is already up to par and second because they may not be appropriate for a realtime streaming codec (which require low latency, capability to adapt to bandwidth variations, handling of packet loss, etc). And we do not need more codecs when Opus already does the job. Also, keep in mind that we need these codecs in our phones, an HD codec like G722 is already good enough so now the game for HD audio codecs is more about efficiency than about even better audio quality.

  2. If your endpoints support Opus I would enable only Opus and a/ulaw if you need to integrate a POTS gateway. Otherwise make it Opus first, g722 second and a/ulaw last. If you have remote endpoints that do not support Opus you may want to consider g729 but these days I think few people actually need g729 (and for g729 you need to pay). Call completion time will be unchanged, call quality will improve if you place your high quality codecs towards the top of your list. I do not understand why you have g722 listed after a/ulaw, gsm, etc. Now, if the call is coming from POTS line, call quality will be the same, not much you can do.

1 Like
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Marcelo, thank you for the detailed advice. I’ve adjusted the codec settings as you indicate. :slight_smile: