On Tue, 01 Jun 2010 14:17:03 +0800, Silvia Pfeiffer
<silviapfeiff...@gmail.com> wrote:
On Tue, Jun 1, 2010 at 3:53 PM, Philip Jägenstedt <phil...@opera.com>
wrote:
On Mon, 31 May 2010 19:33:45 +0800, Silvia Pfeiffer
<silviapfeiff...@gmail.com> wrote:
Hi,
I just came across a curious situation in the spec: IIUC, it seems the
@volume and @muted attributes are only IDL attributes and not content
attributes. This means that an author who is creating an audio-visual
Webpage has to use JavaScript to turn down (or up) the loudness of
their media elements or mute them rather than just being able to
specify this through content attributes.
I've searched the archives and didn't find a discussion or reasons for
this. Apologies if this has been discussed before.
I am guessing the reasons for not having them as content attributes is
that anything that requires muting of audio-visual content is assumed
to need JavaScript anyway.
However, if I have multiple videos on a page, all on autoplay, it
would be nice to turn off the sound of all of them without JavaScript.
With all the new CSS3 functionality, I can, for example, build a
spinning cube of video elements that are on autoplay or a marquee of
videos on autoplay - all of which would require muting the videos to
be bearable. If we added @muted to the content attributes, it would be
easy to set the muted state without having to write any JavaScript.
As for the @volume attribute, I think it would be similarly useful if
an author could control the loudness at which a video or audio file
starts playing back, in particular if he/she knows it is actually a
fairly loud/quiet file.
I'm curious about other people's opinions.
Cheers,
Silvia.
I think both volume and muted could have some use as content
attributes, so
the question is only if the additional complexity for implementations
and
authors. muted is a boolean attribute and would be trivial to support.
volume, however, is a float and last I checked Opera doesn't reflect
[1] any
other float properties. I wouldn't be surprised if it would be a first
for
some other browsers too. Reflecting floats is a little bit annoying (I
tried
when the spec had an aspect attribute for video) because of having to
decide
an arbitrary precision to which to round. That absence of volume should
imply 1.0 (and not 0.0 or NaN) could also be a little bit of a nuisance.
It might be easier if the content attribute for volume was specified
as a percentage value between 0 and 100. Then it would be an integer
only. I'm not sure if this is possible, but it seems we have more
content attributes with these kinds of vlaues (e.g. width/height).
This would make volume even more special, as a float that reflects as an
integer percentage. Just using the existing definition for reflecting a
float would be simpler.
So, I am neither in favor or against of reflecting volume and mute as
content attributes. Implementation is quite simple, but doesn't come for
free unless browsers are already reflecting other float properties.
Mute alone would already be really helpful. I wasn't aware that volume
created such a problem.
I'd be fine with reflecting muted if many people think it would be useful.
I'm not the one to make that judgment though.
Volume isn't a huge problem, just not as trivial as one might suspect.
Another thing to consider is that it is currently impossible to set volume
to a value outside the range [0,1] via the DOM API. With a content
attribute, volume="-1" and volume="1.1" would need to be handled too. I'd
prefer it being ignored rather than being clamped.
[1]
http://www.whatwg.org/specs/web-apps/current-work/multipage/urls.html#reflect
Cheers,
Silvia.
--
Philip Jägenstedt
Core Developer
Opera Software
