[codec] Padding in draft-ietf-codec-opus-07?
"Christian Hoene" <hoene@uni-tuebingen.de> Mon, 25 July 2011 16:11 UTC
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From: Christian Hoene <hoene@uni-tuebingen.de>
To: payload@ietf.org, codec@ietf.org
Date: Mon, 25 Jul 2011 10:33:27 -0400
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Subject: [codec] Padding in draft-ietf-codec-opus-07?
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Hello, I am wondering about a padding feature in draft-ietf-codec-opus-07. It allows you to extend the frame size by filling it up with zeros. I just spoke with the Tim, Jean-Marc and Gregory about this feature. As far as I understood, this feature is required at transcoding gateways to enforce a stream of packets having a constant size (while using UDP). Otherwise, attackers could potentially follow the conversation by observing packet sizes. To my understanding, padding is a feature that can be easily skipped from the codec specification. It violates the layering principle and is intended only for a very specific use cases. On the other side, constant sized frames can be easily supported by keeping the codec parameters fixed. With best regards, Christian Hoene ---------------------------------------------------------------------------- ----- Dr.-Ing. Christian Hoene, University of Tübingen, Computer Science, Chair of Communication Networks, Research Group Interactive Communication Systems (ICS) Sand 13, 72076 Tübingen, Germany, Tel +49 7071 2970532, www.net.uni-tuebingen.de
- Re: [codec] [payload] Padding in draft-ietf-codec… Jean-Marc Valin
- [codec] Padding in draft-ietf-codec-opus-07? Christian Hoene
- Re: [codec] [payload] Padding in draft-ietf-codec… Stephen Botzko
- Re: [codec] [payload] Padding in draft-ietf-codec… Christian Hoene
- Re: [codec] [payload] Padding in draft-ietf-codec… Christian Hoene
- Re: [codec] [payload] Padding in draft-ietf-codec… Jean-Marc Valin
- Re: [codec] [payload] Padding in draft-ietf-codec… Wyss, Felix
- Re: [codec] [payload] Padding in draft-ietf-codec… Christian Hoene