[openal] linear vs cubic resampler?

Chris Robinson chris.kcat at gmail.com
Mon May 18 21:57:22 EDT 2015

On 05/18/2015 09:47 AM, Victorious wrote:
> In the configuration options, there's an option to use a cubic
> resampler. How much difference in audio quality do you get by using
> it vs the default linear one?

There can be a notable difference in quality, but it really depends on 
the sound and the person listening. Some people could probably tell the 
difference easily, others may be able to get the sense of better sound 
but not know why, others may not notice the difference until it's 
pointed out to them, and others may not notice the difference even when 
it is pointed out.

Mathematically speaking, cubic interpolation tries to reconstruct a more 
accurate representation of what the audio signal would be like if it was 
sampled at a different rate. Linear interpolation assumes that there's a 
linear amplitude ramp between any two PCM samples, but that's almost 
never (if ever) the case. Cubic interpolation instead uses a Catmull-Rom 
spline, which attempts to better match the behavior of a signal. It's 
far from perfect, but it does arguably result in less overall 
error/noise compared to linear.

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