[whatwg] Some media element details
Ian Hickson
ian at hixie.ch
Wed Jun 11 17:36:15 PDT 2008
On Fri, 16 May 2008, Antti Koivisto wrote:
>
> [It would be nice to have a read-only attribute (called "playing" for
> example) that would be true when the element is "actively playing".
> Knowing if the playback is progressing is necessary for implementing
> basic playback UIs with JS. It is clumsy and not very obvious that you
> need to do "var playing = !video.paused && !video.ended &&
> video.readyState >= HTMLMediaElement.CAN_PLAY" to get this information.]
>
> For example a simple playing state indicator:
>
> function updatePlayState() {
> var playIndicator = document.getElementById("playIndicator");
> var playing = !video.paused && !video.ended && video.readyState >=
> HTMLMediaElement.CAN_PLAY;
> playIndicator.className = playing ? "playing" : "stopped";
> }
> video.addEventListener("play", updatePlayState);
> video.addEventListener("pause", updatePlayState);
> video.addEventListener("ended", updatePlayState);
> video.addEventListener("waiting", updatePlayState);
I don't think I've ever seen a video player that shows this indicator.
Could you show me an example of a video player UI that does this?
> Knowing whether media is playing or not is needed for other common UI elements
> too, for example to activate/deactivate time display timer,
I don't think the visibility of the time display timer in a typical video
UI is actually directly correlated to the playback state. Again, could you
show an example of this?
> to do play/pause button etc.
The state of a play/pause button is definitely not correlated to the
playback state. It's correlated to the "paused" boolean.
> A direct way to get this information (along with an associated event)
> would be good for API usability I think:
>
> function updatePlayState() {
> var playIndicator = document.getElementById("playIndicator");
> playIndicator.className = video.activelyPlaying ? "playing" :
> "stopped";
> }
> video.addEventListener("playstatechanged", updatePlayState);
>
> Of course it is sort of syntactical sugar...
It's syntactical sugar for something which, in practice, I don't think
anyone would actually use.
If you know of any examples of video players that actually would (if
reimplemented in HTML) make use of this, though, that would be a different
matter.
--
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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