Re: HTML5 Last Call May 2011 & DASH/Adaptive Streaming

Note that there is also an activity in the WHATWG about exposing more
statistics about the media resource to JavaScript, see
http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2011-January/030083.html
. This could address the remaining issues in 4).

Silvia.

On Wed, Feb 16, 2011 at 8:37 AM, Bob Lund <B.Lund@cablelabs.com> wrote:
> There are several “features” that have been referenced that are really
> orthogonal to each other.
>
>
>
> 1)    Exposing alternate media and text tracks for “display”. The
> multi-track media API discussion would cover these in a media format
> independent way. As noted, a proposal is due by 2/21.
>
> 2)    Exposing timed text data (or metadata) to a JavaScript. This is done
> in HTML5 with “Timed Text Tracks”
>
> 3)    Various playback controls, e.g. fast forward, rewind, seek. The
> current <video> controls appear to be adequate in this regard
>
> 4)    Access to DASH (or other adaptive bit rate format) tracks. Here we
> need to distinguish between tracks of the same media at different bit rates
> and additional (to the media) tracks. The latter are addressed in 1) and 2)
> above. The former, access to the different bit-rates is not exposed by any
> adaptive bit-rate player that I’m aware of. The player makes the
> determination of the optimal playback rate and uses the URN in the manifest
> file to retrieve content at that rate. At least one service provider has
> noted it would be useful to have JavaScript control over the delivery
> bit-rate. This could be accomplished by exposing the different bit-rates as
> tracks via 1) above. The track could be labeled by bit-rate and no URN
> information would have to be exposed.
>
>
>
> The adaptive bit-rate delivery issue applies to all adaptive bit-rate
> formats, not just DASH. It would be good if was solved in a general way.
>
>
>
> Regards,
>
> Bob Lund
>
> CableLabs
>
> From: public-web-and-tv-request@w3.org
> [mailto:public-web-and-tv-request@w3.org] On Behalf Of Mark Watson
> Sent: Tuesday, February 15, 2011 11:21 AM
> To: Jean-Claude Dufourd
> Cc: Glenn Adams; Richard Maunder; public-web-and-tv@w3.org
>
> Subject: Re: HTML5 Last Call May 2011 & DASH/Adaptive Streaming
>
>
>
> Discussion on handling multi-track media is already underway on both whatwg
> and HMLT5 lists. See for example Jeroen's
> post: http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2011-February/030454.html
>
>
>
> I think the intention is to include a solution to this. The deadline for
> solution proposals is 21 February.
>
>
>
> This would address choice of language, subtitles, views and accessibility
> tracks. One issue is that DASH has a flexible labeling scheme for track
> types based on URNs, wheras the assumption in the HTML discussions is to use
> a defined list of track types. Personally I think a reasonable resolution of
> this would be to define URNs for the HTML-specified types and leave it at
> that (rather than the opposite approach of persuading HTML to expose URN
> types from DASH.)
>
>
>
> Regarding trick modes, I am not sure what is missing ? The HTML5 media
> element has a "playbackRate" attribute which can be used to play at
> different rates, forwards or backwards.
>
>
>
> ...Mark
>
>
>
>
>
>
>
>
>
>
>
> On Feb 15, 2011, at 9:56 AM, Jean-Claude Dufourd wrote:
>
> There is no question of including DASH technology in HTML5, just means to
> control DASHed media.
> What some participants of the workshop defended was the inclusion of a way
> to deal, within HTML5, with various options offered by DASH, such as choice
> of bit-rate, audio, subtitles, as well as support for trick modes (a.k.a.
> VCR-like controls).
> One possible solution is to add element/attribute syntax around the video
> object to allow that kind of control. Another solution is to add script
> APIs.
> Best regards
> JC
>
> On 15/2/11 18:38 , Glenn Adams wrote:
>
> Even if it were done today, I doubt very much they would reference it from
> the HTML5 spec. There just isn't a strong reason to do so. Besides, they
> have chosen a technology neutral position with respect to both stream media
> formats and transports.
>
>
>
> Glenn Adams
>
> On Tue, Feb 15, 2011 at 8:56 AM, Richard Maunder <rmaunder@cisco.com> wrote:
>
> Hi,
>
>
>
> Interesting session in Berlin last week, thanks to all involved.
>
>
>
> While we wait from the IG process & tools to form, I was interested in the
> implications of the HTML5 Last Call for May, especially the window for
> getting any DASH baseline or other adaptive streaming requirement into the
> spec:
>
>
>
> http://www.w3.org/2011/02/htmlwg-pr.html
>
>
>
> I'm not very familiar with the W3C processes, but my reading of them
> suggests it would be unlikely in this round if not in the spec by May?
>
>
>
> Any thoughts on this?
>
>
>
> Best wishes
>
>
>
> Richard
>
>
>
> Legal boilerplate follows.....
>
> Any views or opinions expressed are solely those of the author and do not
> necessarily represent those of Cisco.
>
>
>
>
>
>
> --
>
> JC Dufourd
>
> Directeur d'Etudes/Professor
>
> Groupe Multimedia/Multimedia Group
>
> Traitement du Signal et Images/Signal and Image Processing
>
> Telecom ParisTech, 46 rue Barrault, 75 013 Paris, France
>
> Tel: +33145817733 - Mob: +33677843843 - Fax: +33145817144
>
>

Received on Tuesday, 15 February 2011 23:35:54 UTC