W3C home > Mailing lists > Public > whatwg@whatwg.org > November 2013

Re: [whatwg] Type strings to specify number of AAC audio channels

From: Ian Hickson <ian@hixie.ch>
Date: Thu, 28 Nov 2013 00:27:13 +0000 (UTC)
To: Bolin Hsu <bhsu@google.com>
Message-ID: <alpine.DEB.2.00.1311280024530.27766@ps20323.dreamhostps.com>
Cc: whatwg@lists.whatwg.org
On Mon, 23 Sep 2013, Bolin Hsu wrote:
>
> Since the royalty for decoding surround sound AAC is higher than stereo 
> AAC, some platforms can decode stereo AAC but not surround sound AAC. 
> But the type string passed to HTMLMediaElement.canPlayType(type) doesn't 
> specify number of channels. I discussed this with some colleagues before 
> I found this list. Has this been covered by standard? Below are some 
> ideas came up during discussion:
> 
> - Use a new codec string, such as 
> HTMLMediaElement.canPlayType('audio/mp4; codecs="aac51"')
> 
> - Add a new parameter, such as
> HTMLMediaElement.canPlayType('audio/mp4; codecs="mp4a.40.2", channels="6")

These seem like appropriate approaches. They would merely need updates to 
the relevant RFCs.


> - Add new element for platform configuration. Some platforms can only
> output stereo audio, so the surround sound is down mixed to stereo. This
> can potentially query the platform if it can really output 6 simultaneous
> audio streams, amount other things:
> HTMLNewElement.getCapability('audio')

I don't think this would be appropriate for an element. As an API, it's a 
client capability query, which, if we support it, would probably belong to 
an API for doing such things. Not sure what the right spec would be for 
that. Anyone?

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Thursday, 28 November 2013 00:27:47 UTC

This archive was generated by hypermail 2.4.0 : Wednesday, 22 January 2020 17:00:14 UTC