Re: Overview of Media Technologies for the Web

Le 01/10/2017 à 10:43, Ingar Mæhlum Arntzen a écrit :
> Francois, all
>
> With the rechartering of the Media and Entertainment IG it makes sense
> to take a fresh look at related technologies, their status and relations
> to important aspects.
>
> I think the document looks well and the structure is intuitive.

Great, thanks for the feedback!


>
> Some comments - mostly related to the Multi-device Timing CG.
>
> - Media Control. One aspect of media that could additionally be
> addressed here relates to flexibility. For example, can a media
> experience be controlled from two devices or by multiple users? Can
> control easily be handed over from one device to another? In a group,
> can media control be symmetric (everybody can control) or asymmetric
> (only a select few can control). This would be an area were exploratory
> work is covered by the Multi-device Timing CG.

The Multi-Device Timing CG is mentioned in the exploratory work section, 
but the description can certainly be improved. Goal is to keep the text 
short for each feature to ease maintenance. Would you have some concrete 
text to propose by any chance? :)


> - Media Rendering vs Content Orchestration. The distinction between
> these two categories at first seems a bit unclear to me, with
> distributed playback being a theme of both.
> The way I read it Media Rendering is focused on standalone playback
> components, plus mechanisms for piping media output to another device.
> Content orchestration seems to be about temporal coordination of
> independent playback components (be it within a single web page or
> across different devices)
> Would this be correct?

That is correct, and it is imperfect indeed. I don't think there exists 
a clean hierarchy to divide technologies, and some of them are listed in 
different places. That's not a bug. I think I'm going to add cross-links 
between pages (for instance, the Media Rendering page mentions the 
Timing Object spec, but the Content Orchestration page will provide more 
details, so it would make sense to link to that page from the Media 
Rendering one)


> - Content Orchestration. Could it rather be named Media Orchestration?
> Within MPEG there is already an on-going initiative [1] using this term.
>
> [1] https://mpeg.chiariglione.org/standards/mpeg-b/media-orchestration

I'm trying to remember how we ended up with Content Orchestration. I 
suppose the idea was that you'll want to orchestrate media and non-media 
content at the same time. I'm fine renaming the section to Media 
Orchestration though. Also, this would mean we'll have "Media" as common 
prefix to all page titles, which seems good.


> - Media Capture. Please include also the aspect of timestamp accuracy in
> captured content. This is of great importance to for any multi-angle
> media productions involving video and audio, and more generally all
> media production where captured media should be precisely relateable to
> a real-world clock (epoch).
>
> Capturing devices may provide a timestamp, but it is rarely known when
> exactly this timestamp was taken (i.e. sometime after requesting an
> image and before the image is available in JS - this could be hundreds
> of milliseconds). Equally important, upstream delays in sensor
> processing pipeline must be known, so that timestamps can be
> compensated. This is analogous to work done in the Web Audio API where
> downstream delays are exposed for media output. As delays may not always
> be known, techniques for measurements and calibrations should likely be
> explored.
> This is addressed as exploratory work within the Multi-device Timing CG.

Isn't it what the latency media track capability would provide?
http://www.w3.org/TR/mediacapture-streams/#def-constraint-latency

I'm fine adding an exploratory work section that mentions discussions on 
timestamp accuracy in captured content. Concrete text welcome as well ;)

Francois.




>
> Best,
> Ingar Arntzen
> chair Multi-device Timing CG
>
>
> 2017-09-28 11:22 GMT+02:00 Francois Daoust <fd@w3.org <mailto:fd@w3.org>>:
>
>     Dear Media and Entertainment Interest Group,
>
>     I have been working on an "Overview of Media Technologies for the
>     Web" document that lists Web technologies that can be used to build
>     media applications and services, and highlights known gaps:
>
>     http://w3c.github.io/web-roadmaps/media/
>     <http://w3c.github.io/web-roadmaps/media/>
>
>     The purpose is to provide a single resource that web developers in
>     the media industry, as well as those involved in the standardization
>     process, can use to find out about the current status of relevant
>     Web technologies.
>
>     The document is structured around different aspects of the media
>     pipeline:
>     - Media rendering
>     - Media control
>     - Media distribution
>     - Media processing
>     - Content orchestration
>     - Media capture
>     - Media application development
>
>     It details Web technologies that apply to each of these aspects,
>     with a short description of what that technology enables in a media
>     context each time. Technologies are sorted in different categories
>     depending on their status:
>
>     - *Well-deployed technologies* are technologies that are finished or
>     nearly finished (e.g. CR and beyond in the W3C Rec track) and that
>     have already found significant adoption among implementations;
>     - *Technologies in progress* list features that have already started
>     their standardization track progress;
>     - *Exploratory work* groups features described in specifications
>     prior to their proper standardization work;
>     - *Features not covered by ongoing work* identify functionalities
>     that are known to be needed for some use cases, but that no existing
>     specification adequately covers
>     - *Discontinued features* point out attempts to develop a feature
>     that was deemed useful at a point in time, but that was stopped for
>     some reason, or that led to some alternative proposal.
>
>     This overview should not be considered as anything else than work in
>     progress right now. Some technologies are probably missing,
>     descriptions should be improved. I wanted to share this document
>     with you for two reasons:
>
>     1. to invite feedback on the document (look and feel, usefulness,
>     structure, content, etc.).
>     2. to check whether the Media and Entertainment Interest Group would
>     be interested to adopt this document as working document.
>
>     In particular, the current charter of the Interest Group says that
>     the group will "maintain a public list of the media features on the
>     Web that it is tracking and investigating. These features will
>     include identified gaps, stable features deployed in browser
>     implementations, as well as features under development in W3C and
>     external groups":
>     https://www.w3.org/2017/03/webtv-charter.html#deliverables
>     <https://www.w3.org/2017/03/webtv-charter.html#deliverables>
>
>     I'm wondering whether the Overview document could provide a good
>     basis for that list, and a good working document to structure
>     discussions within the group. If people are interested, I'll be
>     happy to present that document during one of the IG calls as well as
>     during the group's F2F during TPAC.
>
>     This document is intended to be lightweight to maintain and complete
>     over time. It is part of a series of roadmap-like documents,
>     developed with a common framework. The framework takes care of
>     adding implementation data for each feature/technology listed in the
>     document, and of providing means for users to navigate between
>     pages. The framework is still very sketchy for the time being, but
>     will be maintained and improved by W3C team over time.
>
>     You'll find more information about the ins and outs of such
>     documents in:
>     https://github.com/w3c/web-roadmaps#framework-for-web-technology-roadmaps
>     <https://github.com/w3c/web-roadmaps#framework-for-web-technology-roadmaps>
>
>     Feel free to raise comments on the associated issue tracker:
>     https://github.com/w3c/web-roadmaps/issues/
>     <https://github.com/w3c/web-roadmaps/issues/>
>     (replies to this email are of course welcome as well)
>
>     Thanks,
>     Francois.
>
>
>

Received on Monday, 2 October 2017 08:16:52 UTC