[whatwg] Codecs for <audio> and <video>
ian at hixie.ch
Thu Jul 2 23:21:05 PDT 2009
On Thu, 2 Jul 2009, Charles Pritchard wrote:
> I'd like to see <canvas> support added to the <video> tag (it's as
> natural as <img>).
<video> elements can be painted onto <canvas> elements already; did you
have something more in mind?
> and enable the <audio> tag to accept raw data lpcm),
> just as the <canvas> tag accepts raw data (bitmap).
This is on the list of things to consider in a future version. At this
point I don't really want to add new features yet because otherwise we'll
never get the browser vendors caught up to implementing the same spec. :-)
> add raw pixel support to <video> (via CanvasRenderingContext2D).
Not really sure what this would look like. Can't you just do that with
> And add an event handler when subtitles are enabled / disabled.
This is on the list for the next version. (Generally speaking, control
over subtitles is one of the very next features that will be added.)
> > On Tue, 30 Jun 2009, Dr. Markus Walther wrote:
> > > > Having removed everything else in these sections, I figured there
> > > > wasn't that much value in requiring PCM-in-Wave support. However,
> > > > I will continue to work with browser vendors directly and try to
> > > > get a common codec at least for audio, even if that is just
> > > > PCM-in-Wave.
> I'd think that FLAC would make more sense than PCM-in-Wave, as a PNG
I encourage you to suggest this straight to the relevant vendors. As it
stands, HTML5 is codec-neutral.
> I'd like to see a font analog in audio as well. Canvas supports the font
> attribute, audio could certainly support sound fonts. Use a generated
> pitch if your platform can't or doesn't store sound fonts.
This seems like an issue for the CSS or SVG working groups, who are
working on font-related technologies.
> "User agents should provide controls to enable the manual selection of
> fallback content."
There's no reason the UA couldn't provide an override mechanism to select
an alternative source if the UA vendor so desires.
> "User agents should provide an activation behavior, when fallback
> content is required, detailing why the primary content could not be
There's no reason why UAs can't do that now. The spec doesn't prohibit
> Many non-technical users will want to know why there is a black screen
> (or still image), even though they can hear the audio.
This kind of situation is of course why we really want to have a common
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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