Re: [MMUSIC] Scope of RTP payload types in BUNDLE?

Paul Kyzivat <pkyzivat@alum.mit.edu> Mon, 27 May 2013 19:14 UTC

Return-Path: <pkyzivat@alum.mit.edu>
X-Original-To: mmusic@ietfa.amsl.com
Delivered-To: mmusic@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id BC04521F967F for <mmusic@ietfa.amsl.com>; Mon, 27 May 2013 12:14:02 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.11
X-Spam-Level:
X-Spam-Status: No, score=-0.11 tagged_above=-999 required=5 tests=[AWL=0.327, BAYES_00=-2.599, FH_RELAY_NODNS=1.451, HELO_MISMATCH_NET=0.611, RDNS_NONE=0.1]
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 t+8hr-tYZFgU for <mmusic@ietfa.amsl.com>; Mon, 27 May 2013 12:13:57 -0700 (PDT)
Received: from qmta04.westchester.pa.mail.comcast.net (qmta04.westchester.pa.mail.comcast.net [IPv6:2001:558:fe14:43:76:96:62:40]) by ietfa.amsl.com (Postfix) with ESMTP id 917F421F93EF for <mmusic@ietf.org>; Mon, 27 May 2013 12:13:54 -0700 (PDT)
Received: from omta08.westchester.pa.mail.comcast.net ([76.96.62.12]) by qmta04.westchester.pa.mail.comcast.net with comcast id h78D1l0040Fqzac547DtoL; Mon, 27 May 2013 19:13:53 +0000
Received: from Paul-Kyzivats-MacBook-Pro.local ([50.138.229.164]) by omta08.westchester.pa.mail.comcast.net with comcast id h7Dt1l00u3ZTu2S3U7Dtne; Mon, 27 May 2013 19:13:53 +0000
Message-ID: <51A3B070.1090006@alum.mit.edu>
Date: Mon, 27 May 2013 15:13:52 -0400
From: Paul Kyzivat <pkyzivat@alum.mit.edu>
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:17.0) Gecko/20130509 Thunderbird/17.0.6
MIME-Version: 1.0
To: mmusic@ietf.org
References: <749DCA95-2D40-46B3-9A3D-E63356C7A2C1@csperkins.org> <1892A917-C408-4E8F-AB19-206ED508762C@csperkins.org> <7594FB04B1934943A5C02806D1A2204B1C3799BC@ESESSMB209.ericsson.se> <4EDA75BD-D753-4153-929B-10427274224D@csperkins.org> <7594FB04B1934943A5C02806D1A2204B1C3799EE@ESESSMB209.ericsson.se>, <599C780A-F483-470E-91F2-68DBA605C79C@csperkins.org> <7594FB04B1934943A5C02806D1A2204B1C379D6E@ESESSMB209.ericsson.se>, <64C06EE8-A16D-4C3E-8A11-D6400F620A8E@csperkins.org> <7594FB04B1934943A5C02806D1A2204B1C379DC8@ESESSMB209.ericsson.se> <71ED9E54-DF0C-4DB9-A7F4-09A0BC90B177@csperkins.org>
In-Reply-To: <71ED9E54-DF0C-4DB9-A7F4-09A0BC90B177@csperkins.org>
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Content-Transfer-Encoding: 7bit
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20121106; t=1369682033; bh=FBl85KnD0KAbZAhO+hHtP59qiJzQXE2n+HKwSZIZblw=; h=Received:Received:Message-ID:Date:From:MIME-Version:To:Subject: Content-Type; b=gDm5nKcAWoi4Efe/u+/OmHAItAdcXMT43Yg3pSxG+B67VsOU3wmFs/c+VUKkT8G6k rJY+wPcNSEIzcRNuhG5xJsmmbfV+EPii67/Ll8ffaRhJh4AbwbxYv/0mTtIaV0DJfw GE3FsaEuYfdTCBx231AjtOjE7rApLK3LHb33LJuEkiC8XX8LMgEGL9JO8ARJ6eY48w e7t8ms2eOXzGnx6DASefSF8WbYuvmc/eYnKLs9LNAYTDGdRU27p+Khd6K3Dbm+GWQS qza6+Ww8zDOd6IwMNBu08EWi76qw4oQaw+aRaZvp8uHT/cDFYl7hSc/HbbqkV3WdTo WCRzquki2iBlA==
Subject: Re: [MMUSIC] Scope of RTP payload types in BUNDLE?
X-BeenThere: mmusic@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Multiparty Multimedia Session Control Working Group <mmusic.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/mmusic>, <mailto:mmusic-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/mmusic>
List-Post: <mailto:mmusic@ietf.org>
List-Help: <mailto:mmusic-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/mmusic>, <mailto:mmusic-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 27 May 2013 19:14:02 -0000

On 5/27/13 2:52 PM, Colin Perkins wrote:

>>>> In the example above the same payload format, within the same RTP session, is used in two separate m- lines. But, I still can't use the same PT value for both m- lines, even if the payload format is the same, can I?
>>
>>> Why not? I don't see any problem mapping the same payload type to the exact same payload format in two different m= lines.
>>
>> But, when I receive media with that payload format, how do I know to which m- line it "belongs", as the same PT value is used for both m- lines?
>
> You don't. If you care about that, you need to either use distinct PT values for each m= line, or signal SSRCs.

I assert that if you don't care about associating a packet to a 
particular m-line in a bundle that you don't need to use bundle.

So if you used bundle, you must care, and so there must be a way to 
achieve that association.

The reason you care is because doing so allows you to discover all the 
other things in that media section of the SDP that may be pertinent to 
this packet.

	Thanks,
	Paul