Subject: Re: [codec] FEC?

From: Koen Vos <[email-masked]>
Date: Fri, 12 Nov 2010 21:28:45 +0100 (CET)

Only the SILK part has in-band FEC (and right now it's not even enabled, but soon it will be).

SILK's in-band FEC is special because 
- it adds FEC only for packets the encoder deems most sensitive (e.g speech onsets)
- the FEC data is coded at a lower bitrate by quantizing more coarsely.
These make the in-band FEC more efficient than an over-the-top scheme.

For music the advantage of in-band FEC seems smaller than for speech.

koen.

----- Original Message -----
From: "Christian Hoene" <[email-masked]>
To: [email-masked]
Sent: Thursday, November 11, 2010 4:46:03 AM
Subject: [codec] FEC?

Hi,

just a few questions on the forward error correction feature. Some
months ago I had a brief look at the FEC feature of Silk, which was a
simple add to the codec. However, only these days I came to think about
it.

1) The support of FEC in Opus, is it support in all coding modes or only
in the Silk mode?
2) Does it provide features that is not already covered by IETF FEC
schemes like the "FEC Framework" or AVT RFC 5109??
3) If it has nothing new, why not to skip it?

Christian

--------------------------------------------------------------- Dr.-Ing.
Christian Hoene
Interactive Communication Systems (ICS), University of Tübingen
Sand 13, 72076 Tübingen, Germany, Phone +49 7071 2970532
http://www.net.uni-tuebingen.de/

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From: "Christian Hoene" <[email-masked]>
Date: Sun, 14 Nov 2010 03:55:50 +0100

> These make the in-band FEC more efficient than an over-the-top scheme.

Cool, sounds good!

Christian