IETF Logo Mail Archive

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

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

Return-Path: <harald@alvestrand.no>
X-Original-To: codec@ietfa.amsl.com
Delivered-To: codec@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 35689131083 for <codec@ietfa.amsl.com>; Wed, 13 Feb 2019 00:46:28 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.899
X-Spam-Level:
X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id A7t27k1FRxNc for <codec@ietfa.amsl.com>; Wed, 13 Feb 2019 00:46:25 -0800 (PST)
Received: from mork.alvestrand.no (mork.alvestrand.no [IPv6:2001:700:1:2::117]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id B1715131047 for <codec@ietf.org>; Wed, 13 Feb 2019 00:46:25 -0800 (PST)
Received: from localhost (localhost [127.0.0.1]) by mork.alvestrand.no (Postfix) with ESMTP id C720B7C3E59; Wed, 13 Feb 2019 09:46:23 +0100 (CET)
X-Virus-Scanned: Debian amavisd-new at alvestrand.no
Received: from mork.alvestrand.no ([127.0.0.1]) by localhost (mork.alvestrand.no [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id e3UwAlphEii3; Wed, 13 Feb 2019 09:46:22 +0100 (CET)
Received: from hta-hippo.lul.corp.google.com (unknown [IPv6:2620:0:1043:12:88ab:4fa2:7af4:100d]) by mork.alvestrand.no (Postfix) with ESMTPSA id 3C70E7C0C58; Wed, 13 Feb 2019 09:46:22 +0100 (CET)
To: Jean-Marc Valin <jmvalin@jmvalin.ca>, codec@ietf.org
References: <15e1a439-bdc1-cd5f-8c9b-ee02c0248a30@alvestrand.no> <cb4b10dc-f9d2-43af-eb78-5d27649ad849@jmvalin.ca>
From: Harald Alvestrand <harald@alvestrand.no>
Openpgp: preference=signencrypt
Message-ID: <181650d0-db82-dde6-6624-fdb27ee03917@alvestrand.no>
Date: Wed, 13 Feb 2019 09:46:21 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <cb4b10dc-f9d2-43af-eb78-5d27649ad849@jmvalin.ca>
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Content-Language: en-US
Archived-At: <https://mailarchive.ietf.org/arch/msg/codec/SKjCV79SwU3gtRFq9EWbWPc3tCU>
Subject: Re: [codec] SDP mapping for > 2 channels in OPUS?
X-BeenThere: codec@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Codec WG <codec.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/codec>, <mailto:codec-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/codec/>
List-Post: <mailto:codec@ietf.org>
List-Help: <mailto:codec-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/codec>, <mailto:codec-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 13 Feb 2019 08:46:29 -0000

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
>>
>>
>> _______________________________________________
>> codec mailing list
>> codec@ietf.org
>> https://www.ietf.org/mailman/listinfo/codec
>>
> _______________________________________________
> codec mailing list
> codec@ietf.org
> https://www.ietf.org/mailman/listinfo/codec

v2.23.0 | Report a Bug | By Email