[whatwg] Apple Proposal for Timed Media Elements
ian at hixie.ch
Fri Oct 12 15:03:48 PDT 2007
On Wed, 21 Mar 2007, Robert Brodrecht wrote (in response to Apple's
> > If the presentation of timed media by the user agent has been disabled, if
> > the resource has an unsupported type, or if the preparations for its
> > presentation fail either because of a protocol failure or because the format
> > of the media is unrecognized, the user agent must fire an error event on the
> > element and display the element's fallback content, if available.
> So, we have some fallback control. That is good, as it is lacking from
> WHAT WG at the moment and was something I'm concerned about. This is
> how I intuitively felt it should work. I'm glad that is specified.
The way the <video> element now works in the HTML5 proposal is not quite
this -- the fallback is only used if the browser doesn't support <video>
at all, not if it doesn't support the codec. The primary reasons for this
is to stop the bouncing around of content. This is similar to how <iframe>
works. Fallback to different formats is provided via <source>.
> > The controller attribute is a boolean attribute. If the attribute is
> > present, the user agent must display a user interface which allows the
> > user to control the media element. The height attribute on the element
> > does not include the size of the controller, it is the size of the
> > video element only
> I like being able to specify this, but the height of the controller needs to:
> 1) Be set normatively in this specification. If the height of the
> controller area changes across browsers, it's going to be a source of
> irritation for developers.
> 2) Be set in CSS (as well as positioning options... I'd guess through a
> pseudo element like :controller?).
We'll address this in the rendering section in due course.
> > When the src attribute is set, the user agent must immediately begin
> > to download the specified resource unless the user agent cannot
> > support video/audio, or its support for video/audio has been disabled
> One reason I like YouTube is that the download is user-initiated. If I
> include YouTube content on my site, they see a nice thumbnail from the
> video and a big play button. If they are on dial-up, they don't have to
> download it. Autodownload, to me, is flawed. I know I can set up the
> love to see an "autodownload" attribute to complement "autoplay" or use
> "autoplay=0" to disable the auto download. A way to add a thumbnail
> would be nice while not auto downloading.
The spec has an autoplay="" attribute now, and can stall downloading the
content for as long as the user desires.
> > The DOM attribute currentRate is the rate at which a media element is
> > currently playing.
> I'm guessing this would be in frames per second? Is it the frames per
> second it is playing or the available frames per second encoded in the
In the spec it's a multiple of the native rate.
On Thu, 22 Mar 2007, Chris Double wrote:
> > Looping is useful for more presentational uses of video. Start and end
> > time are useful in case you want to package a bunch of small bits of
> > video in one file and just play different segments, similar to the way
> > content authors sometimes have one big image and use different
> > subregions. Or consider looping audio, or a single audio file with
> > multiple sound effects. These are two examples.
> support for it with loopStartTime, etc? If an event is raised when the
> video reaches endTime then event handler could then restart it.
On Sat, 24 Mar 2007, Kevin Marks wrote:
> For smooth looping, you need to have the next buffer ready and cued up
> when the previous one finishes. Doing this consistently with a roundtrip
> 30fps, you can make the interval, but audio at 48khz means you are more
> likely to hear a click or gap.
The spec now does it declaratively.
On Wed, 21 Mar 2007, Eric Carlson wrote:
> > I'm guessing this would be in frames per second? Is it the frames per
> > second it is playing or the available frames per second encoded in the
> > video?
> No, it is a multiple of the file's intrinsic (or "natural") rate.
> "Frames per second" loses meaning quickly with digital media files,
> where individual frames can have arbitrary duration (true even for
> animated GIF files).
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