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Re: Specificity in the Web Audio API spec

From: Chris Rogers <crogers@google.com>
Date: Mon, 2 Apr 2012 12:08:15 -0700
Message-ID: <CA+EzO0nG+rMYz+Vh56FHq8dowM2nkRndVL1uFAPzKAo2T9EYSA@mail.gmail.com>
To: robert@ocallahan.org
Cc: Jussi Kalliokoski <jussi.kalliokoski@gmail.com>, "Wei, James" <james.wei@intel.com>, "public-audio@w3.org" <public-audio@w3.org>
On Sat, Mar 31, 2012 at 5:02 AM, Robert O'Callahan <robert@ocallahan.org>wrote:

> It seems to me that the spec should define exactly what the ideal behavior
> of each processing algorithm is, and ask implementations to approximate
> that ideal as closely as they can. Then an implementation should be able to
> implement features based solely on the spec, and get results very close to
> the results of all other implementations, up to some small error.
>

Robert, I think that's a good way to describe it.  People have pointed out
some details I still need to clarify, and I hope to update the Web Audio
specification soon given this feedback.


>
> Canvas-2d is pretty close to this. Where it isn't, it needs to be fixed.
> (Font rasterization is a special case because available fonts, font
> selection and font rasterization techniques intentionally vary across
> platforms, partly due to different aesthetic choices on each platform. I
> don't think we want platform-specific aesthetic choices creeping into our
> audio APIs.)
>

I don't think we'll have to deal too much with OS-level differences in
terms of the rendering.  HRTF spatialization attempts to re-create the
filtering and ITD (inter-aural time delays) of real humans.  So although
there is certainly an ideal in terms of frequency responses and ITD based
on average human physiology, in practice actual recordings from real people
are recorded in anechoic chambers and used for the processing.  These
recordings can be shared across implementations, and are not limited in any
way to a specific OS.  But I think it would be acceptable for different
implementations to use specific different recordings as long as they come
close to achieving the ideal effect.

Chris


>
> Rob
> --
> “You have heard that it was said, ‘Love your neighbor and hate your
> enemy.’ But I tell you, love your enemies and pray for those who persecute
> you, that you may be children of your Father in heaven. ... If you love
> those who love you, what reward will you get? Are not even the tax
> collectors doing that? And if you greet only your own people, what are you
> doing more than others?" [Matthew 5:43-47]
>
>
Received on Monday, 2 April 2012 19:08:45 GMT

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