Re: [codec] A concrete proposal for requirements and testing

[Stefan Hacker <[e-mail]>]

Hello,

I am writing this on behalf of the developers of the OSS VoIP tool Mumble. Since the 1.2.0 release of our software in December 2009, which integrated CELT as the new default codec to complement Speex, hundreds of thousands of users have sent and listened to millions of hours of CELT VoIP audio of different versions using Mumble. The response was hugely positive, with the most recent versions of CELT reportedly outperforming Speex even at low bit-rates. CELT, despite not even being finalized, has also been picked up by a number of other well known VoIP tools. It goes without saying that SILK has seen an even greater amount of usage, and is well known for its quality.

We have been closely following the development of Opus as well as the tests being performed by others and are excited about the prospect of being able to utilize Opus in future versions of our software. From the tests we have seen and participated in so far, we expect Opus in its current state to outperform pure CELT in our specific use-case and want to integrate and distribute it to our users sooner rather than later. We will do so as soon as licensing allows us to, which will generate millions of hours of real-world listening tests.

It is the reality of most Internet based applications that they are in testing and production at the same time. Publishing a proposed standard does not set it in stone forever, it just opens the field for testing on a much, much broader scale. We believe in the current state of Opus and are eager to show that belief by delivering it to all of our users.

Thank you all for your great work.

Regards,
Thorvald Natvig,
Mikkel Krautz,
Benjamin Jemlich,
Stefan Hacker