Re: [mediaqueries4][css-speech] Media queries for multichannel audio ?

On Fri, Mar 29, 2013 at 8:58 AM, Florian Rivoal <florian@rivoal.net> wrote:

> Hi,
>
> Your request has not fallen off the radar, don't worry. We just have a
> very full plate, and it sometimes takes time before things get on the top
> of the agenda.
>
> I think at this point, the most useful thing to do would be to collect
> uses cases, so that we can best judge if the solution proposed would be
> effective at solving them. The examples you gave in your previous mail are
> useful, but not really what I would call use cases though.
>
> "Providing the right number of audio channels in a video streamed using
> the media attribute of the <source>  element or in the Media Source case by
> JavaScript using mediaMatch()" is a use case (maybe two).
>

Ok, that may be sufficient for our purposes. I will think whether we have
any other use-cases. I guess the examples I gave explain what is meant by
the "right number of audio channels".


>
> I would be interested in knowing whether people want to use it for
> something else. Does it have applications in the context of css-speech, for
> instance? If yes, what are their expectations? This is the kind of thing
> I'd like to hear about before taking any decision.
>
> Also, just to clarify, for your use case, assuming a 5.1 capable
> environment, do you want the number of channels detected to be 5 or 6?


6. And for 7.2 it is 9. I think the multichannel specifications go up to
something like 21.3 (!), but the number of channels is sufficient to make
the decision as to which media source to use.

...Mark


>
>
>  - Florian
>
>
> On Fri, 29 Mar 2013 16:39:16 +0100, Mark Watson <watsonm@netflix.com>
> wrote:
>
>  Florian, all,
>>
>> What should be the next steps on this - should I provide more detailed use
>> cases ? (in email, or is there a wiki ?)
>>
>> ...Mark
>>
>> On Sat, Mar 23, 2013 at 10:06 AM, Mark Watson <watsonm@netflix.com>
>> wrote:
>>
>>
>>>
>>> Sent from my iPhone
>>>
>>> On Mar 23, 2013, at 6:20 AM, "Florian Rivoal" <florian@rivoal.net>
>>> wrote:
>>>
>>> > On Wed, 20 Mar 2013 16:03:48 +0100, Mark Watson <watsonm@netflix.com>
>>> wrote:
>>> >
>>> >> Florian, all,
>>> >>
>>> >> How do I progress this issue ? Do I need to file a bug ? (where?) Do I
>>> need to join the WG ?
>>> >
>>> >
>>> > Leaving your other two issues aside for the moment, and focusing on the
>>> mutichannel part.
>>> >
>>> > There is no need to join the WG, raising the issue in this mailing list
>>> and following up on conversations (as you are doing) is normally enough.
>>> Once we reach sufficient consensus, or at least understand well enough
>>> the
>>> questions that needs to be answered, we can take it to one of our weekly
>>> conference calls to try and decide one way or the other.
>>> >
>>> > From where I stand, I see a few open questions with your proposal:
>>> >
>>> > * Should it be number of channels, or number of speakers?
>>> > To answer this questions, we would need a variety of use cases to be
>>> described, to be able to judge which one fits best.
>>> >
>>>
>>> It's the number of output channels, because:
>>> - you can't know the number of speakers - the audio output may be a
>>> digital one connected to an A/V receiver or other equipment which is then
>>> connected to the speakers.
>>> - some systems use audio processing techniques to simulate surround sound
>>> without the usual number of speakers - for example soundbars.
>>>
>>> Some use-cases, all involving content available in stereo and 5.1,
>>> provided as alternative <source> elements in an HTML media element:
>>> - a PC that supports the 5.1 codec, but is outputing the audio over a
>>> stereo analogue output jack
>>> - a PC that is outputing the audio over a 5.1 digital audio output
>>> (S/PDIF, HDMI)
>>> - a TV that is outputing the audio over internal stereo speakers, with
>>> only a capability for basic downmixing
>>> - a TV that is outputing the audio over a 5.1 capable digital audio
>>> output
>>> - a TV with internal signal processing that is capable of simulating
>>> surround sound from a 5.1 input through less than 6 speakers
>>>
>>> > * If number of speakers, can that be reliably detected?
>>> > I am not an expert on the topic, but it seems to be that the OS (let
>>> alone the browser) is not necessarily aware of how many physical speakers
>>> there are.
>>> >
>>> > * It seems to me that your main use case for this media query would not
>>> actually be applying different styles based on the situation, but feed
>>> that
>>> back into javascript, and use it there. If that's the case, I wonder if
>>> media queries is the best tool to solve the problem.
>>>
>>> It's a resource selection problem, which is done today on the media
>>> element using media queries (the media attribute of the <source> element)
>>> and could be done in the Media Source case by JavaScript using the
>>> mediaMatch() function (ensuring that the script approach matches the
>>> declarative approach).
>>>
>>> ...Mark
>>> >
>>> >
>>> > - Florian
>>> >
>>>
>>>
>>>
>