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Re: Codecs for <video> and <audio>

From: Ian Hickson <ian@hixie.ch>
Date: Tue, 30 Jun 2009 06:14:59 +0000 (UTC)
To: Doug Schepers <schepers@w3.org>
Cc: public-html@w3.org
Message-ID: <Pine.LNX.4.62.0906300559270.16244@hixie.dreamhostps.com>
On Tue, 30 Jun 2009, Doug Schepers wrote:
> > 
> > I have therefore removed the two subsections in the HTML5 spec in 
> > which codecs would have been required, and have instead left the 
> > matter undefined, as has in the past been done with other features 
> > like <img> and image formats, <embed> and plugin APIs, or Web fonts 
> > and font formats.
> 
> It's not clear to me why you also had to remove the audio codecs (last I 
> check, WAV was in there... has there been some change in the IP claims 
> there?)...

I didn't really see much value in having the section purely to require a 
small subset of WAVE functionality. WAVE in this context is only really 
useful during development, and since codecs are going to be a mess anyway, 
the author can just use whatever debugging-specific codec his main UA 
supports instead. (I've also received requests from browser vendors to not 
require WAVE support in the first place, though I have up to this point 
managed to convince them to keep WAVE support regardless.)


> Also, are you really not able to get agreement on image formats, such as 
> PNG? Who is unwilling to implement GIF and PNG (and maybe APNG and MNG)?

It hasn't really been necessary, browser vendors have historically 
implemented similar formats without the HTML spec having to get involved. 

(Regarding MNG: Mozilla has indicated a lack of desire to support MNG; 
they controversially removed support a few years back.)


> As far as I know, those are all Royalty-Free, with open-source libraries 
> readily available, and at least GIF and PNG are in widespread use on the 
> Web, so there should be no barriers and strong incentives to mandating 
> support for those formats.  Why are these not mandated?

There is already interoperability amongst the image formats, so there 
isn't much to gain by doing so, as far as I can tell.

The only reason we were considering having a section for <video> was to 
encourage the browser vendors to implement a common codec. This isn't 
necessary for image formats.

Having said that, I think it would be quite useful to have a "browser 
profile" specification that lists all the various specifications that 
browser vendors have agreed that they should implement. That would 
probably be out of scope of this group's charter, though.


> Mandated formats increase the consistency and value of the open Web 
> platform, which is centered around HTML, and HTML5 should express and 
> reinforce that.

I don't think that mandating formats actually affects what browsers 
implement, in practice. We can only mandate what they're already willing 
to implement anyway.


> > If anyone knows of another way to get consensus on this issue, please 
> > do let the working group know.
> 
> Within W3C, we continue to try to find a solution to this problem, not 
> only for the decoding, but the encoding as well.  If we make progress, 
> you can be sure that we will let the HTML WG know right away.

Excellent, thanks. I shall similarly continue to seek solutions for this.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Tuesday, 30 June 2009 06:15:35 GMT

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