Re: [web-audio-api] (AudioBufferSourceNodePlaybackRate): AudioBufferSourceNode.playbackRate not strictly defined (#95)

> [Original comment](https://www.w3.org/Bugs/Public/show_bug.cgi?id=17378#5) by Joe Berkovitz / NF on W3C Bugzilla. Fri, 02 Aug 2013 19:34:03 GMT

@Ehsan: I had no intention of assuming any particular algorithm (and tried to call this out -- sorry if it was unclear). Of course linear interpolation is not a preferred choice. I suppose that a literal interpretation of my proposal could suggest linear interpolation, but that was not the intention.

The proposal specifies a sequence of {data window, effective sampling rate} pairs with fractional sample-offset boundaries that form the input to an arbitrary interpolation algorithm. How the interpolator makes use of this sequence is not a concern. A nonlinear interpolator can work with as much of the sequence as it likes, processing arbitrarily large batches of data points at a time.

Of course in practice an implementor would probably not accumulate such a sequence and apply an interpolation algorithm to it, this is an idealized behavior for specification purposes.

If this approach turns out to be too naîve I welcome an improved recasting of it. I think the important aspect of it has to do with the way that playback progress through the buffer is affected by a time-varying playback rate, and I found an idealized cursor the easiest way to express this progress.

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