Re: [codec] SDP mapping for > 2 channels in OPUS?

Harald Alvestrand <harald@alvestrand.no> Wed, 13 February 2019 08:46 UTC

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To: Jean-Marc Valin <jmvalin@jmvalin.ca>, codec@ietf.org
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From: Harald Alvestrand <harald@alvestrand.no>
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Subject: Re: [codec] SDP mapping for > 2 channels in OPUS?
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On 12. feb. 2019 23:41, Jean-Marc Valin wrote:
> Hi Harald,
>
> There's no such spec yet. It probably would not be too hard to come up
> with one, starting from the RFC7845 and RFC8486. That being said, I
> think we would need to define a new payload and corresponding media
> subtype to avoid compatibility problems with RFC7587.

Thanks for confirming the absence of specs. The hackaround that Google
folks are trying is to send 5.1 as 3 OPUS stereo channels, which doesn't
make me particularly happy.

>
> Cheers,
>
> 	Jean-Marc
>
>
> On 02/12/2019 03:50 PM, Harald Alvestrand wrote:
>> Hi,
>>
>> I wonder if there exists some specification for multichannel OPUS in SDP
>> - I have searched for it and missed it.
>>
>> I note that RFC 8486 (ambisonics) doesn't say anything about SDP
>> considerations.
>>
>> Harald
>>
>>
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