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FAQ

Why bandpass filter only goes to 8000 Hz?

The audio you upload is converted to mono-channel 16 kHz which translates to 8 kHz (half of the sampling frequency). Read on Nyquist rate for explanation.

My files take long to upload

Consider reducing the sampling frequency to 16kHz, number of channels to 1 and compressing the file to e.g. mp3. There is an excellent cross-platform tool called SoX that can help you. If you have a lot of files that you want to process, here's how you can process them in parallel on Linux / Mac:

find . -name '*.wav' -type f -print0 | parallel -0 sox --norm {} -r 16000 --channels 1 your-path/{.}.mp3

The command: * Finds all wav * Pipes then to parallel tool that will execute subsequent call in parallel * SoX normalises the audio, resamples to 16 kHz and one channel and then converts to mp3

Read parallel cheat sheet and full manual for details.

How to install the software?

There are a few approaches: * Start from scratch from the repo * Use Docker image * Check with me about producing a Virtual Machine image with the software. We could use e.g. VirtualBox.