Rnonlin

Rnonlin is a metric that measures the amount of perceptible distortion in a distorted track, when compared to its original 'clean' counter.

It was developed by Moore, Tan and others in the paper:

Predicting the Perceived Quality of Nonlinearly Distorted Music and Speech Signals

I have implemented this metric in software, via Matlab. This software as well as LUFS can be found in the linked folder.

What it essentially does is:

• Model the filtering effects of the outer & middle ear on both track versions,
• Filters both track versions through an ERB based Gammatone filter array, to simulate the basilar membrane
• Creates a weighting coefficient set using the maximum level comparisons for the distorted version for each packet of a 30ms sliding window
• Finds the maximum cross-correlation between both versions of the track
• Does this for lags of -10ms to + 10ms
• weights these normalised maximum cross correlations, so all used coefficients sum to 1
• sums across the 40 filtered versions of the signal per packet
• mean averages per packet

Papers like http://projekter.aau.dk/projekter/files/9852082/07gr1061_Thesis.pdf show that it gives excellent correlation with listener perceived levels of distortion.

I will use this to derive how much perceptual distortion is in a track, which is important as I am trying to stay on the fringe of distortion perceptibility, as not to incur a response derived by the fact that the distortion is loud and present, and more the effect of the effect of the particulars of the distortion in and of itself.

https://onedrive.live.com/redir?resid=563e4881c8b0b60!6782&authkey=!ALzVdJrzlx7dS68&ithint=folder%2c