The May Build of AVChat 3 (due next week) will have support for the Speex audio codec introduced in Flash Player 10. This will mean better audio quality,lower latency and less bandwidth usage than before!

This is one of the reasons we’ve switched to Flash Player 10 for AVChat 3 starting with the April Build, other changes will include separate volume control for each web cam and proper behaviour when the users denies access to his web cam and mic.

The old codec we’ve been using so far in AVChat 3, the NellyMoser Asao codec, was introduced in Flash Player 6 and was licensed by Adobe from NellyMoser Inc. . Because NellyMoser Inc. had the full rights to the audio codec this made it hard and expensive for developers to convert files encoded with NellyMoser to AAC or MP3. This was one of the main complains against NellyMoser Asao.

The Speex codec, introduced in FP10, is optimized for voice and provides better audio quality using less bandwdith. It is also open souce so you can decode it and convert it to mp3 or aac (ffmpeg already decodes Speex) without needing any licenses. It also provides more levels (11) of quality as opposed to NellyMoserAsao (only 5).

In this table comparing compression rates for Nelly Moser Asao and Speex in Flash Player you can see that Speex at its highest setting needs half the bandwidth NellyMoser Asao uses at its highest setting:

Speex Nelly Moser Asao
Required bandwidth
in Kbps
Required bandwidth
in Kbps
0 3.95 5 11.025
1 5.75 8 16
2 7.75 11 22.05
3 9.80 22 44.1
4 12.8 44 88.2 (default in AVChat 3
so far)
5 16.8
6 20.6 (default in AVChat 3
from now on)
7 23.8
8 27.8
9 34.2
10 42.2

We will update our article covering changing the audio quality in AVChat 3 in time for the release next week, however, no changes will be needed as the new build will default to using the new Speex codec for audio. Until next week you can test the new audio quality in our online demo of AVChat 3.

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