[linux-audio-user] Stretching with very high accuracy

[Fons Adriaensen]

On Thu, Jun 08, 2006 at 05:42:36PM -0400, Paul Winkler wrote:

> Given the very small amount of drift (53 ms / hour), we're talking about 
> inserting maybe 1 sample per 30000.  I submit that nobody will notice
> if you just insert a copy of an adjacent sample, and if you 
> want better than that, interpolation between two adjacent
> samples would be even smoother.

I tried a more elaborate scheme some time ago (for Aeolus): instead
of just inserting on sample, replace N by N+1 samples using higher
order interpolation, with N up to 64. It could still be heard on some
sounds.

One way to resample accurately with ratios near to unity is to use
FFT based convolution to find the samples at fractional position
a/b and (a+1)/b, then interpolate linearly between those.

-- 
FA

Follie! Follie! Delirio vano e' questo!