Re: [codec] Multi-mode frame concatenation

Jonathan Lennox <jonathan@vidyo.com> Fri, 29 July 2011 18:37 UTC

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From: Jonathan Lennox <jonathan@vidyo.com>
To: "bens@alum.mit.edu" <bens@alum.mit.edu>
Date: Fri, 29 Jul 2011 14:37:21 -0400
Thread-Topic: [codec] Multi-mode frame concatenation
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Subject: Re: [codec] Multi-mode frame concatenation
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On Jul 29, 2011, at 2:13 PM, Benjamin M. Schwartz wrote:

> On 07/29/2011 01:53 PM, Ralph Giles wrote:
>> Do you mean using lower values of M when the config field indicates
>> the frame has a longer duration?
> 
> Nope.  I mean that once M is invalid, the other two bits are also
> available for signaling.  I would not regard M=49, p=1, v=0 (byte==113) as
> a multi-mode packet indicator, so it's still available for something else.

It would probably be a good idea to explicitly reserve some extension values for the external container, analogous to the way that H.264 reserves NAL Unit Types 24-31.  This ensures that the RTP payload format can both support a mode where it directly places Opus packets into an RTP payload, and also (if necessary) a mode where it add some additional framing or other transport-related data around them.

--
Jonathan Lennox
jonathan@vidyo.com