General acoustic utilities

General tools for .wav or .flac audio files

WAV to FLAC and FLAC to WAV conversion

agate’s conversion tools allow conversion from raw .dat files to either .wav or .flac. Some users may later want to convert between .wav and .flac. Rather than reprocessing raw .dat files, use flac.exe to encode/decode to/from .flac.

There are several ways to do this (free GUIs, command line, MATLAB audioread/audiowrite).

A simple and reasonably efficient method is a MATLAB wrapper-type function packaged with agate: wav2flac and flac2wav. These call flac.exe via command line but have the added functionality to operate over a directory of files, check for proper paths, and track progress.

% set path to flac software, input directory of WAV files, output directory for FLAC files
path_flac = 'C:\Users\User.Name\programs\flac-1.5.0-win\Win64\flac';

% to convert from WAV to FLAC
inDir = 'F:\wavFiles';
outDir = 'F:\flacFiles\'; % important it ends in slash! Function has built in check for this

wav2flac(path_flac, inDir, outDir)

% to convert from FLAC to WAV
inDir = 'F:\flacFiles';
outDir = 'F:\wavFiles\'; % important it ends in slash! Function has built in check for this

flac2wav(path_flac, inDir, outDir)

R-based conversion tool

If you prefer to use R, a similar wrapper for the command line tool is available in the crputils package.

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Downsample (decimate) audio files

The decimateDir function can be used to downsample a directory of .wav or .flac files to one or more lower sample rates at once.

The original sample rate must be evenly divisible by each new sample rate (i.e., the decimation factor must be an integer); decimateDir checks this automatically.

By default, output files are written to a new folder alongside the input folder, named [folder]_decimated_[new sample rate] (e.g., wav_decimated_1kHz), with the new sample rate appended to each output filename (e.g., WISPR_260810_170505.flac becomes WISPR_260810_170505_1kHz.flac). Output folders can also be specified manually — one per requested sample rate.

% downsample a folder of files to two new sample rates at once (1000 Hz and 10 kHz)
% output folders will be created automatically alongside the input folder
decimateDir([1000 10000], 'G:/glider/wav');

% OR specify output folders manually, one per new sample rate, in the same order
decimateDir([1000 10000], 'G:/glider/wav', ...
    {'G:/glider/wav_decimate_1kHz', 'G:/glider/wav_decimate_10kHz'});

If a run is interrupted partway through, files that have already been decimated will be skipped automatically on the next run (based on whether the expected output files already exist). Set overwrite to true to force reprocessing instead.

% force reprocessing/overwrite of all files, even if already decimated
decimateDir([1000 10000], 'G:/glider/wav', ...
    {'G:/glider/wav_decimate_1kHz', 'G:/glider/wav_decimate_10kHz'}, ...
    overwrite=true);

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