Re: [codec] [payload] Frames to Packets in draft-ietf-codec-opus-07?

"Benjamin M. Schwartz" <bmschwar@fas.harvard.edu> Wed, 27 July 2011 19:21 UTC

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Date: Wed, 27 Jul 2011 15:21:02 -0400
From: "Benjamin M. Schwartz" <bmschwar@fas.harvard.edu>
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To: Jonathan Lennox <jonathan@vidyo.com>
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Cc: "codec@ietf.org" <codec@ietf.org>, "payload@ietf.org" <payload@ietf.org>
Subject: Re: [codec] [payload] Frames to Packets in draft-ietf-codec-opus-07?
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On 07/27/2011 03:10 PM, Jonathan Lennox wrote:
> Based on my reading of the Opus spec, it looks like splitting should be possible, relatively trivially.  Aggregation, however, is only possible if the packets to be aggregated have the same value for the Opus TOC byte.

That is a correct reading of the Opus spec as of Opus-02 and later.  Prior
to Opus-02, the spec also described a packet mode that could contain
frames of different types, allowing arbitrary aggregation.  I believe it
was removed because the authors expected that it would be rarely used, and
removing it allowed them to improve the efficiency of more common cases.

--Ben