Autoloop is an application for finding multiple loops in wave files and and saving them into to the sampler chunk. It is designed primarily for Hauptwerk pipe samples (which contain a long sustain block which is to be looped) and has not been tested for other purposes.

What does Autoloop search for?

Autoloop does not perform crossfading at the loop points. It searches for points that will connect perfectly when looped. The selection algorithm currently uses two criteria to determine this:

  • Power matching - the RMS power is computed for a fixed number of samples at each candidate loop point. The ratio of the power at this point to the power at another point forms one quality factor.
  • Sample matching - the ratio of the sample at the loop point is taken against the sample at another loop point forming another quality factor. This is performed on a user-configurable number of following samples from these loop points to generate additional quality factors.

All of the quality factors are then multiplied and if the resultant quality is above a certain level (user configurable), the loop will be saved to the file.

Usage Notes

The algorithm is quite basic (I think), but performs well. The configuration file autoloop.conf bundled with the download is a plain text configuration file which can be opened and modified using Notepad or another text editor. It is very descriptive and will help you setup Autoloop to perform well with your samples.

The package can be downloaded here.

Nick Appleton's audio, electronics and software projects… and blog thing