Re: UAAG 2.0 guidelines for video

Correction to my previous email:

The HTML5 media elements already have an attribute to control the playback rate:

           attribute float defaultPlaybackRate;

(see http://www.whatwg.org/specs/web-apps/current-work/multipage/video.html#media-elements).


So, my questions will only be for contrast and brightness.

Sorry about the confusion.

Regards,
Silvia.


On Wed, May 5, 2010 at 9:23 AM, Silvia Pfeiffer
<silviapfeiffer1@gmail.com> wrote:
> Hi Jim,
>
> I have read of all these requirements. It's quite an impressive list
> and will certainly be useful to John as he is putting together the
> requirements list discussed in the last phone conference of the media
> a11y subgroup in the HTML5 a11y TF.
>
> I believe that most of these requirements are already being taken care
> of or are in development - much of it is not yet present in browsers,
> but that is more an implementation issue than a specification issue.
> It is probably important for this group to continue to monitor
> progress on these issues and to remind browser vendors to implement
> these required features.
>
> I am, however, concerned about the  following two requirements, since
> they are fundamental requirements on media resources that are not
> regarded in today's HTML5 media elements and I am not aware of any
> plans to introduce them.
>
>
> On Wed, May 5, 2010 at 4:50 AM, Jim Allan <jimallan@tsbvi.edu> wrote:
>>
>> 4.9.5 Playback Rate Adjustment for Prerecorded Content: The user can adjust
>> the playback rate of prerecorded time-based media content, such that all of
>> the following are true (Level A):
>>
>>    * The user can adjust the playback rate of the time-based media tracks
>> to between 50% and 250% of real time.
>>    * Speech whose playback rate has been adjusted by the user maintains
>> pitch in order to limit degradation of the speech quality.
>>    * Audio and video tracks remain synchronized across this required range
>> of playback rates.
>>    * The user agent provides a function that resets the playback rate to
>> normal (100%).
>
>
> Would it make sense to introduce an attribute on the media elements
> that allows changing the playback rate? Or is this solely a feature of
> the underlying media framework and thus a browser issue?
>
> Or in other words: is the playback rate something that we want a Web
> page author to be able to specify or is it enough if it is a feature
> that the Web browser provides to the user? If it is the first, we need
> a new attribute, if it is the latter, we need to lobby the browser
> vendors and potentially work towards introducing a recommendation into
> the HTML5 specification that UAs should provide this functionality.
>
>
>> 4.9.11 Adjust Playback Contrast and Brightness. User has ability to control
>> the contrast and brightness of the content within the playback viewport.
>
> This is actually a very similar issue to the playback rate. Again, we
> have to answer the question whether this is something that we want to
> give the Web page author the ability to influence or just something
> between the UA and the user.
>
>
> Best Regards,
> Silvia.
>

Received on Wednesday, 5 May 2010 00:17:45 UTC