[rtcweb] m-line recycling

Eric Rescorla <ekr@rtfm.com> Mon, 12 May 2014 04:51 UTC

Return-Path: <ekr@rtfm.com>
X-Original-To: rtcweb@ietfa.amsl.com
Delivered-To: rtcweb@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 554FF1A03EE for <rtcweb@ietfa.amsl.com>; Sun, 11 May 2014 21:51:06 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.976
X-Spam-Level:
X-Spam-Status: No, score=-1.976 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, FM_FORGED_GMAIL=0.622, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7, WEIRD_PORT=0.001] autolearn=ham
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 8WK_x1iQiE0N for <rtcweb@ietfa.amsl.com>; Sun, 11 May 2014 21:51:05 -0700 (PDT)
Received: from mail-wg0-f52.google.com (mail-wg0-f52.google.com [74.125.82.52]) by ietfa.amsl.com (Postfix) with ESMTP id B60121A03EA for <rtcweb@ietf.org>; Sun, 11 May 2014 21:51:04 -0700 (PDT)
Received: by mail-wg0-f52.google.com with SMTP id l18so6176552wgh.11 for <rtcweb@ietf.org>; Sun, 11 May 2014 21:50:58 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:from:date:message-id:subject:to :content-type; bh=lLjL5zC3DzT2YUifJ4RDLDZKou0YzJrKzYQCqKFdERo=; b=EyDE6iiSuUS9TzTkCqnK4s6LPvey4EXI08PnwzJ9pW4xmRf4cuBWcHHSPpVAYQQjpI OMTYVPrh3+WTqM5pzBgNcd4oDTOUnuA4VEyTzlOX6wNZYrDTTQmKv/5tetMb/l8/kUjx sllNIzE0DJ67QrmjpbNJ+UPdrF1JTt+JpXcN1IwY4HWHnreZpf8QaeV4PFdNVGF4IIvK zZ8geayJkLGKkIr+DjI60kEd5YaDLe6yRjrWdkslX/nziXmHBzySJ1sPEKnArI2IUq3t 5zjhlC+/klYGIZflaeS29nnm4DakQy9wOlbXUcJ5+LOWM0htHHULpNbo/I2D5VLod5BK Gf8Q==
X-Gm-Message-State: ALoCoQnuBRi4AVHjvGc3jy/WO3VSTrkUs0+YbbbATasfBMrMlNIIurorauMTPzSrxVmrUPW0VFT0
X-Received: by 10.180.94.226 with SMTP id df2mr13451213wib.1.1399870258447; Sun, 11 May 2014 21:50:58 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.216.218.198 with HTTP; Sun, 11 May 2014 21:50:18 -0700 (PDT)
X-Originating-IP: [74.95.2.168]
From: Eric Rescorla <ekr@rtfm.com>
Date: Sun, 11 May 2014 21:50:18 -0700
Message-ID: <CABcZeBPXKt6EeEa+PzRqWoa9194Ewte3MQik9T6TmaTTiGK_+w@mail.gmail.com>
To: mmusic WG <mmusic@ietf.org>, "rtcweb@ietf.org" <rtcweb@ietf.org>
Content-Type: multipart/alternative; boundary=f46d04447e617cf71a04f92cb156
Archived-At: http://mailarchive.ietf.org/arch/msg/rtcweb/DNsiRpXNE833cs9D_ViKYibP8E4
Subject: [rtcweb] m-line recycling
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.15
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: Mon, 12 May 2014 04:51:06 -0000

The JSEP spec specifies m-line recycling:

 o  If any MediaStreamTracks have been added, and there exist m=
      sections of the appropriate media type with no associated
      MediaStreamTracks (i.e. as described in the preceding paragraph),
      those m= sections MUST be recycled by adding the new
      MediaStreamTrack to the m= section.  This is done by adding the
      necessary "a=msid", "a=ssrc", and "a=ssrc-group" lines to the
      recycled m= section, and removing the "a=recvonly" attribute.

Based on the minutes from IETF 89, we were going to take this to mmusic.

http://etherpad.tools.ietf.org:9000/p/notes-ietf-89-rtcweb?useMonospaceFont=true

Thoughts?

-Ekr


https://github.com/rtcweb-wg/jsep/issues/21