Re: [rtcweb] Comments to use-cases/reqs document

Dzonatas Sol <> Tue, 12 July 2011 17:23 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 997A221F8C07 for <>; Tue, 12 Jul 2011 10:23:31 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2.08
X-Spam-Status: No, score=-2.08 tagged_above=-999 required=5 tests=[AWL=-4.308, BAYES_00=-2.599, GB_SUMOF=5, J_CHICKENPOX_13=0.6, RCVD_IN_DNSWL_LOW=-1, SARE_SUB_OBFU_Q1=0.227]
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id hPyKdEy7XY6r for <>; Tue, 12 Jul 2011 10:23:27 -0700 (PDT)
Received: from ( []) by (Postfix) with ESMTP id 7670E21F8C04 for <>; Tue, 12 Jul 2011 10:23:27 -0700 (PDT)
Received: by iwn39 with SMTP id 39so5839319iwn.31 for <>; Tue, 12 Jul 2011 10:23:27 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=MOWWzWDoWzf06aw/96gjzMXgMUoAIOdzRysOiOHUoMA=; b=YTYGeAx6rrtyHqi4T8OkopD2LaEsVeKq45BWrxhH5sTloS95T/Wm6bwiS9syAYcevC j7M3cSB5N27RptBAMagTtt0COUiUwdbevDTtkzIV24CoyTPquBiRFn+RIYqm+AT8BnOt I4jrHaPDn3j6eKQxril721Wxn955NwnHz8Q58=
Received: by with SMTP id jj6mr170265icb.203.1310491405526; Tue, 12 Jul 2011 10:23:25 -0700 (PDT)
Received: from [] ([]) by with ESMTPS id v16sm8425655ibe.34.2011. (version=TLSv1/SSLv3 cipher=OTHER); Tue, 12 Jul 2011 10:23:23 -0700 (PDT)
Message-ID: <>
Date: Tue, 12 Jul 2011 10:23:15 -0700
From: Dzonatas Sol <>
User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv: Gecko/20110505 Icedove/3.0.11
MIME-Version: 1.0
To: Stephan Wenger <>
References: <>
In-Reply-To: <>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Cc: "" <>
Subject: Re: [rtcweb] Comments to use-cases/reqs document
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Tue, 12 Jul 2011 17:23:31 -0000

The crystal radio is "not quite simple" if we use standard memory 
technology (or hard-ware version).

Given signal-to-noise, the maximal fractal surface may seem to be the 
union of point-to-point. That is falsifiable, the millisecond is not 
unless one proves one. ASCII presents "the choice" to support that. 
Standard? "Not my business."

The event horizon for real-time appears only simulated (by us), and I 
like the religions topics on this, for science by science.

For example,

We could express: millisecond := <square>alpha+beta</square>

We could write that with MathML, yet the published MathML is not in 
plain English, enough. Reason? Maybe. How do you know if that means 
"square root of the value of alpha plus beta" or "alpha squared plus 
beta squared, and that the square root of that value". Which quote is in 
present tense? The obvious.

The constance is the power of two, a magic number in computer science, 
yet for mathematics, a real number? 1 + 1.

Elementary support for that number? Some say not their business.

Let's revisit the scale factor of affine transformations:

How would re-write that equation to remove the magic numbers in order to 
have the pure scalar value? Replace the first two and last two with 
"alpha" and "omega", and format with XML to MathML.

Is the truth, the pure scalar value, of two relative to the affine 
transformation by Wolfram? Ballard's method is E=mcc, so not always. 
Mathematicians think relative to "Energy equals mass times speed of 
light to the power of two."

Use-case for "real-time": law of two.

On 07/12/2011 08:09 AM, Stephan Wenger wrote:
> That's fine, but then you need to add at least one more use case:
> point-to-point, and not quite simple...
> Stephan
> On 7.12.2011 08:02 , "Harald Alvestrand"<>  wrote:
>> On 07/12/11 16:35, Stephan Wenger wrote:
>>> Hi Harald,
>>> If you define "simple" as "minimum functionality", then there should
>>> also
>>> be a use case "not quite so simple; offer at least the user experience
>>> you
>>> get from a Skype client today".  That use case may well turn out to be
>>> more popular than the "simple" use case according to your definition.
>>> However, my preference would be not to assume minimalistic use cases,
>>> but
>>> rather tune the level of mandation of the requirements.  (So I'm in
>>> Stefan's camp -- keeping the number of use cases reasonable)
>> I'm all for "reasonable", but my "reasonable" may be different from
>> yours.... the sum of all requirements should indeed allow us to build
>> equivalents to Skype or Google Talk on top of this platform (except for
>> the parts that don't make sense, of course :-) ), but I find it easier
>> to talk about auto-zoom to keep head size constant (for instance - at
>> least one Skype beta supported that) as a separate use case, not merged
>> with the "basic use case".
>>> Stephan
>>> On 7.12.2011 07:17 , "Harald Alvestrand"<>   wrote:
>>>> On 07/12/11 13:58, Stefan H�kansson LK wrote:
>>>>>>> All,
>>>>>>> some comments to
>>>>>>> <
>>>>>>> ir
>>>>>>> ements/?include_text=1>
>>>>>>> 3. The "Video Size Change" use case derives F22; but that is already
>>>>>>> derived in "Simple Video Communication Service". I propose to remove
>>>>>>> the "Video Size Change" use case.
>>>>>> I disagree with this proposal.
>>>>>> While the "resizing" requirement is in "simple video communication
>>>>>> service" as
>>>>>> "The users can change the display sizes during the session", I
>>>>>> believe
>>>>>> the basic use case does not derive the requirement that the change in
>>>>>> video size be communicated to the other party.
>>>>>> I would propose the following changes:
>>>>>> - Reinstate the text below:
>>>>>> 4.2.4.  Video Size Change
>>>>>>  Description
>>>>>>       Alice and Bob are in a video call in their browsers and have
>>>>>>       negotiate a high resolution video.  Bob decides to change the
>>>>>> size
>>>>>> of
>>>>>>       the windows his browser is displaying video to a small size.
>>>>>>       Bob's browser regenerates the video codec paramters with Alice's
>>>>>>       browser to change the resolution of the video Alice sends to
>>>>>> match
>>>>>>       the smaller size.
>>>>> My preference is always to keep the number of use cases down.
>>>> We may have a difference of style here - I prefer to have explicit use
>>>> cases that show only a single action or attribute that needs to be
>>>> supported, which means that the number of use cases tends to be high.
>>>> I think this is especially important for the situation where a WG has
>>>> to
>>>> decide to drop an use case because no agreed-upon implementation can be
>>>> found.
>>>>>     Could we not just add a sentence to the current "Simple Video
>>>>> Communication Service" use case so it reads something like "The users
>>>>> can change the sizes of the video displays during the session. Changes
>>>>> of the display size are communicated from the displaying browser to
>>>>> the
>>>>> one sending the stream so that the video codec parameters can be
>>>>> changed
>>>>> accordingly."
>>>> As per above - I would prefer the "Simple Video Communication Service"
>>>> to be as simple as possible. Even resizing the window locally is more
>>>> than "as simple as possible" - the Gtalk video client for my phone
>>>> doesn't support that.
>>>>> But my preference is not strong - I'm happy to reinsert the use case
>>>>> if
>>>>> people think so.
>>>>>>  Derived Requirements
>>>>>>       F22 ( It SHOULD be possible to modify video codec parameters
>>>>>> during a
>>>>>>       session.)
>>>>> F22 now reads "The browser SHOULD use encoding of streams suitable for
>>>>> the current rendering (e.g. video display size) and SHOULD change
>>>>> parameters if the rendering changes during the session"
>>>>>> - Change the text of F22 to be:
>>>>>>      It SHOULD be possible for one party to request a change in video
>>>>>> codec parameters, such as size,
>>>>>>      during a session, and for the other party to react to this
>>>>>> request.
>>>>> I think "party" is very vague. What does it mean - the browser, the
>>>>> user, the web app?
>>>> Since this is the IETF WG - the "party" is the browser, user and web
>>>> app
>>>> together; somehow the desire for a change has to be communicated across
>>>> the network, and that's the requirement I think needs to be in the IETF
>>>> requirements list.
>>>> The corresponding API requirement (which I'm not sure how to formulate
>>>> -
>>>> all this may go on in the browser and need no explicit API) needs to go
>>>> into the W3C requirements list.
>>>> _______________________________________________
>>>> rtcweb mailing list
> _______________________________________________
> rtcweb mailing list

--- ---
Web Development, Software Engineering
Ag-Biotech, Virtual Reality, Consultant