Convert your Audio files to any FFmpeg codec using python's pydub. For handling conversions, FFmpeg needs to be installed.
Set path to environmental variables or set path of FFmpeg's binary explicitly.
pydub.AudioSegment.converter = r"C:\\path\\to\\ffmpeg.exe"
In file-flac.py, replace format="mp3" with any other FFmpeg supported format. Also, get chunks of .raw files for audio processing using file-raw.py.
Don't wish to use python, work directly from command line.
cmd> ffmpeg -i input.mp3 output.flac
For transcribing large audio files, Google's speech-to-text requires audio with FLAC extention & mono channel,
cmd> ffmpeg -i output.flac -ac 1 mono.flac