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

[Stephan Wenger <[e-mail]>]

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" <[e-mail]> 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"<[e-mail]>  wrote:
>>
>>> On 07/12/11 13:58, Stefan Håkansson LK wrote:
>>>>>> All,
>>>>>>
>>>>>> some comments to
>>>>>>
>>>>>> 
>>>>>><http://datatracker.ietf.org/doc/draft-ietf-rtcweb-use-cases-and-requ
>>>>>>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
>>>>>
>>>>> 4.2.4.1.  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.
>>>>> 4.2.4.2.  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
>>> [e-mail]
>>> https://www.ietf.org/mailman/listinfo/rtcweb
>>
>>
>