Re: [rtcweb] Separating stream manipulation from the SDP loudness (Re: Proposed Plan for Usage of SDP and RTP)

Ted Hardie <ted.ietf@gmail.com> Sun, 10 March 2013 18:22 UTC

Return-Path: <ted.ietf@gmail.com>
X-Original-To: rtcweb@ietfa.amsl.com
Delivered-To: rtcweb@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 65BC421F88A0 for <rtcweb@ietfa.amsl.com>; Sun, 10 Mar 2013 11:22:20 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.577
X-Spam-Level:
X-Spam-Status: No, score=-2.577 tagged_above=-999 required=5 tests=[AWL=0.023, BAYES_00=-2.599, NO_RELAYS=-0.001]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id TAEJ7W3xsjKJ for <rtcweb@ietfa.amsl.com>; Sun, 10 Mar 2013 11:22:19 -0700 (PDT)
Received: from mail-ie0-x235.google.com (mail-ie0-x235.google.com [IPv6:2607:f8b0:4001:c03::235]) by ietfa.amsl.com (Postfix) with ESMTP id 63A2421F8895 for <rtcweb@ietf.org>; Sun, 10 Mar 2013 11:22:19 -0700 (PDT)
Received: by mail-ie0-f181.google.com with SMTP id 17so3817981iea.40 for <rtcweb@ietf.org>; Sun, 10 Mar 2013 11:22:19 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:cc:content-type; bh=lh2JWD4DL51LoDblr6i4DnxyhDbOfzUEDEFoeCHL9+Y=; b=BTW5k+3w5KovYCX9j566+hVtWNzffQBS7QjkvuyG5v8tw9llQ7t+hKji1HuWXpefEb La+MEeUGJMMjAj7IeJaDRITdcWaBsBJyu/rOHSLcRlmJr7Ap/XkluiKzT0uGIvhPzHWG sHRhOfV/yWXK8PquJcVOKxvgLg6PebnCaAQvemF4Ouy0mhwPBR+XeBLgMzuoDhK1Xh3w 1My1XVU9+ywY/al2mDc9D2aZdP6FPjbCY4XgJsuvGCu7d78FAKDwUQ0l9d6ZF+YC/BJJ 4ujisT8k1G6c7UEmbhZX0S1kESkH3DJbPyaS+xWhtR62se9+3EJFor5iYGQ/llxi9SXy pSpA==
MIME-Version: 1.0
X-Received: by 10.43.88.134 with SMTP id ba6mr3753598icc.18.1362939738984; Sun, 10 Mar 2013 11:22:18 -0700 (PDT)
Received: by 10.43.135.202 with HTTP; Sun, 10 Mar 2013 11:22:18 -0700 (PDT)
In-Reply-To: <CAJrXDUEL_5BjWVaP4Fu7sY+P7kj1GVz3q3_z=wUtgyzMUnud2w@mail.gmail.com>
References: <CD5D3F35.B22B%robin@hookflash.com> <B9549E2E-6E68-4F34-A9C0-1F050285A70A@acmepacket.com> <CABkgnnXCio-Dw7dN5yfSjeRf3wG2oWow_M2mU-Y49TedSAPQmg@mail.gmail.com> <CAHBDyN6CFTix3W9qWgC1T0O36t4SajL3hMXaHOdkat-p5TY_xA@mail.gmail.com> <CABcZeBMLdEkFZq5rMOY0texKb4DtFQ-O86JkC17kJihxv6Dj8w@mail.gmail.com> <CAHBDyN6mM-rT315uSbeTQfKuCiVwsEDhi7Q6DEbt8pjiJ_4i6g@mail.gmail.com> <CAHp8n2nz=NZb=UaevUSS7GRSBpvn-v9_=QHz6iddnZzyx5-TSQ@mail.gmail.com> <CAJrXDUETwfY7ZvaXO_1Bq8gs8pOTgALQE8FiimrUX7sfuEpDsw@mail.gmail.com> <CAHp8n2kcEHcz11LOYYMZ3-nv2PYQKu=z6M=dsQ_H5JuR8ND7hQ@mail.gmail.com> <513B5D98.2070601@alvestrand.no> <CAJrXDUEL_5BjWVaP4Fu7sY+P7kj1GVz3q3_z=wUtgyzMUnud2w@mail.gmail.com>
Date: Sun, 10 Mar 2013 14:22:18 -0400
Message-ID: <CA+9kkMCzV-0LdyzuTuyY_X7UHagVknpuTF3zk1WCeZ2SzgL-zQ@mail.gmail.com>
From: Ted Hardie <ted.ietf@gmail.com>
To: Peter Thatcher <pthatcher@google.com>
Content-Type: text/plain; charset=ISO-8859-1
Cc: rtcweb@ietf.org
Subject: Re: [rtcweb] Separating stream manipulation from the SDP loudness (Re: Proposed Plan for Usage of SDP and RTP)
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <rtcweb.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/rtcweb>
List-Post: <mailto:rtcweb@ietf.org>
List-Help: <mailto:rtcweb-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sun, 10 Mar 2013 18:22:20 -0000

On Sun, Mar 10, 2013 at 12:02 AM, Peter Thatcher <pthatcher@google.com> wrote:
> There's a difference between the resolution that you open the camera at and
> the resolution you send over the network at.  Does the current constraints
> API let you capture at one resolution and send at another?  Also, does it
> let you change the send resolution on the fly?
>
Just to make sure I understand the use case here, is the idea that you
open the camera at one resolution, potentially using that for a
recording or local display, then send a different resolution to the
peer?  I ask because I'm trying to understand how this control would
map to the connection objects--is there always a mediastream track
consuming the "native" resolution of the camera?

regards,

Ted


> These are important controls that, as far as I know, are not currently
> supplied to the application.  They could potentially be supplied by SDP, new
> methods, or as you suggest, perhaps even as some kind of constraint.  But I
> don't think they are currently provided.
>
> On Mar 9, 2013 7:54 PM, "Harald Alvestrand" <harald@alvestrand.no> wrote:
>>
>> As usual, I'm trying to use subject line change in order to achieve some
>> separation of concerns...
>>
>> On 03/07/2013 10:22 PM, Silvia Pfeiffer wrote:
>>>
>>> Agreed, but it's also not sufficient. SDP is not "programmer friendly"
>>> enough because it has too many details that are protocol-details only and
>>> it's too hard to see the semantic bits in SDP and ignore the rest.
>>>
>>> For example: the programmer wants to say - I want to get this video
>>> resolution, this audio bitrate & channels, I want to use this camera and
>>> this microphone for this call. Having to manipulate SDP directly for this is
>>> a programmer's nightmare.
>>
>>
>> I think we've been over exactly those pieces, and our current proposed
>> solution is called the Media Stream API and the constraints mechanism - and
>> they have exactly nothing to do with SDP, or even with PeerConnection.
>>
>> I don't think we've got it to be "unproblematic" yet, but also, I don't
>> think SDP, JSON or even the offer-answer model is either the problem or the
>> solution on this set of functionalities.
>>
>> Or did I misunderstand something basic?
>>
>>                Harald
>>
>> _______________________________________________
>> rtcweb mailing list
>> rtcweb@ietf.org
>> https://www.ietf.org/mailman/listinfo/rtcweb
>
>
> _______________________________________________
> rtcweb mailing list
> rtcweb@ietf.org
> https://www.ietf.org/mailman/listinfo/rtcweb
>