Re: [rtcweb] JSEP-bis and WebRTC-Extensions Section 5.2

Tim Panton <thp@westhawk.co.uk> Sun, 07 May 2023 10:16 UTC

Return-Path: <thp@westhawk.co.uk>
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 E73FBC1516E2 for <rtcweb@ietfa.amsl.com>; Sun, 7 May 2023 03:16:46 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.795
X-Spam-Level:
X-Spam-Status: No, score=-1.795 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, HTTPS_HTTP_MISMATCH=0.1, RCVD_IN_ZEN_BLOCKED_OPENDNS=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001, URIBL_DBL_BLOCKED_OPENDNS=0.001, URIBL_ZEN_BLOCKED_OPENDNS=0.001] autolearn=no autolearn_force=no
Received: from mail.ietf.org ([50.223.129.194]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id IH6c8N-b_b6u for <rtcweb@ietfa.amsl.com>; Sun, 7 May 2023 03:16:43 -0700 (PDT)
Received: from smtp002.apm-internet.net (smtp002.apm-internet.net [85.119.248.221]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 8F4E2C151554 for <rtcweb@ietf.org>; Sun, 7 May 2023 03:16:41 -0700 (PDT)
Received: (qmail 84275 invoked from network); 7 May 2023 10:16:38 -0000
X-APM-Out-ID: 16834545988427
X-APM-Authkey: 255286/0(159927/0) 28
Received: from unknown (HELO zimbra003.verygoodemail.com) (85.119.248.218) by smtp002.apm-internet.net with SMTP; 7 May 2023 10:16:38 -0000
Received: from localhost (localhost [127.0.0.1]) by zimbra003.verygoodemail.com (Postfix) with ESMTP id 9BB4E81845; Sun, 7 May 2023 11:16:38 +0100 (BST)
Received: from zimbra003.verygoodemail.com ([127.0.0.1]) by localhost (zimbra003.verygoodemail.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id 9608OXrEi2LP; Sun, 7 May 2023 11:16:38 +0100 (BST)
Received: from smtpclient.apple (unknown [192.67.4.77]) by zimbra003.verygoodemail.com (Postfix) with ESMTPSA id 5B3AD8178C; Sun, 7 May 2023 11:16:38 +0100 (BST)
From: Tim Panton <thp@westhawk.co.uk>
Message-Id: <61AC7C19-2806-483F-9526-637DB5D46104@westhawk.co.uk>
Content-Type: multipart/alternative; boundary="Apple-Mail=_39A9C496-85E3-41C1-90C8-E600D406CF1D"
Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3731.500.231\))
Date: Sun, 07 May 2023 11:16:27 +0100
In-Reply-To: <HE1PR07MB44416F5D6CCD8940D5974E3193709@HE1PR07MB4441.eurprd07.prod.outlook.com>
Cc: Justin Uberti <justin@fixie.ai>, "rtcweb@ietf.org" <rtcweb@ietf.org>
To: Christer Holmberg <christer.holmberg=40ericsson.com@dmarc.ietf.org>
References: <CAPn_nMPhh0x5-_BKa0xF595Y8LXo5oRQjJqFgxFLtcCf+-FpOw@mail.gmail.com> <HE1PR07MB44416F5D6CCD8940D5974E3193709@HE1PR07MB4441.eurprd07.prod.outlook.com>
X-Mailer: Apple Mail (2.3731.500.231)
Archived-At: <https://mailarchive.ietf.org/arch/msg/rtcweb/UkXY6rph4N7sKJnsHAi9B5zBO6I>
Subject: Re: [rtcweb] JSEP-bis and WebRTC-Extensions Section 5.2
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.39
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: <https://mailarchive.ietf.org/arch/browse/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, 07 May 2023 10:16:47 -0000

I was also thinking about this too - and I somewhat agree.

We could replace ‘supported' with 'supported by the current application’ since at a high level what this change does is to differentiate between extensions that the library (libwebrtc etc) can support vs extensions the current application wants to support.

It also makes it clearer that this is an editorial change.

T.

> On 7 May 2023, at 11:10, Christer Holmberg <christer.holmberg=40ericsson.com@dmarc.ietf.org> wrote:
> 
> Hi,
> 
> I have issues with the proposed change.
> 
> First, AFAIK, "enabled" is not used in any other O/A specification.
> 
> Second, my reading of "supported" is that it is something that the endpoint is actually willing to/capable of using within the session. 
> 
> Third, within the JSEP O/A procedures, "supported" is used for other features (e.g., FEC mechanisms). Using other terminology for one feature will only confuse the reader, in my opinion.
> 
> Fourth, if it is unclear what "supported" really means we should rather clarify that.
> 
> Regards,
> 
> Christer
> 
> Sent from Outlook for iOS <https://aka.ms/o0ukef>
> From: rtcweb <rtcweb-bounces@ietf.org> on behalf of Justin Uberti <justin@fixie.ai>
> Sent: Saturday, May 6, 2023 3:30:33 AM
> To: rtcweb@ietf.org <rtcweb@ietf.org>; superuser@gmail.com <superuser@gmail.com>
> Subject: [rtcweb] JSEP-bis and WebRTC-Extensions Section 5.2
>  
> The WebRTC W3C WG is working on an extension spec <https://w3c.github.io/webrtc-extensions/#rtp-header-extension-control-modifications> that suggests behavior for RTP header extension O/A that conflicts slightly with the current version of JSEP. Rather than have this sort of ad-hoc extensions extension to JSEP in the W3C spec, it was suggested that we could apply a tiny patch to JSEP before JSEP-bis is finalized (it's currently in the RFC Editor state). Murray was supportive of this but wanted to make sure the WG was fully behind this change first.
> 
> For context, Section 5.2 in the W3C extension spec basically says that WebRTC endpoints can control the extensions that are in use, and as a result O/A negotiation should a) use only the extensions that are enabled by the endpoint, and b) always reoffer all extensions, rather than the previously negotiated set.
> 
> I've made a PR that captures this request at https://github.com/rtcweb-wg/jsep/pull/1033/files <https://protect2.fireeye.com/v1/url?k=31323334-501d5122-313273af-454445555731-45f3175ddedc0fdc&q=1&e=d500064c-f63a-47ed-b1ec-2ff879fda6f4&u=https%3A%2F%2Fgithub.com%2Frtcweb-wg%2Fjsep%2Fpull%2F1033%2Ffiles>, and it basically makes two surgical changes:
> 1) replaces the use of "supported RTP header extensions" with "enabled RTP header extensions"
> 2) changes the text around "extensions... present in the most recent answer" to instead say "extensions... enabled on the associated transceiver" (similar to how codecs are handled in JSEP).
> 
> Please let me know if this sounds reasonable to you or you have concerns.
> 
> Thanks,
> Justin
> 
> _______________________________________________
> rtcweb mailing list
> rtcweb@ietf.org
> https://www.ietf.org/mailman/listinfo/rtcweb