Voximplant now can save audio without compression. Such audio records can then be downloaded and used for machine learning and other tasks where compression would introduce unwanted data modifications. Audio will be saved as 8KHz 16 bit mono:

// Example for the record method of the Call class function
call.record({lossless: true});
// Example for the Recorder class
require(Modules.Recorder);
// ...
const recorder = VoxEngine.createRecorder({lossless: true});
call.sendMediaTo(recorder);