Joining .wav files without writing on disk in Python

Question

I have a list of .wav files in binary format (they are coming from a websocket), which I want to join in a single binary .wav file to then do speech recognition with it. I have been able to make it work with the following code:

audio = [binary_wav1, binary_wav2,..., binary_wavN] # a list of .wav binary files coming from a socket
audio = [io.BytesIO(x) for x in audio]

# Join wav files
with wave.open('/tmp/input.wav', 'wb') as temp_input:
    params_set = False
    for audio_file in audio:
        with wave.open(audio_file, 'rb') as w:
            if not params_set:
                temp_input.setparams(w.getparams())
                params_set = True
            temp_input.writeframes(w.readframes(w.getnframes()))

# Do speech recognition
binary_audio = open('/tmp/input.wav', 'rb').read())
ASR(binary_audio)

The problem is that I don't want to write the file '/tmp/input.wav' in disk. Is there any way to do it without writing any file in the disk?

Thanks.

Answer 1

The general solution for having a file but never putting it to disk is a stream. For this we use the io library which is the default library for working with in-memory streams. You even already use BytesIO earlier in your code it seems.

audio = [binary_wav1, binary_wav2,..., binary_wavN] # a list of .wav binary files coming from a socket
audio = [io.BytesIO(x) for x in audio]

# Join wav files

params_set = False
temp_file = io.BytesIO()
with wave.open(temp_file, 'wb') as temp_input:
    for audio_file in audio:
        with wave.open(audio_file, 'rb') as w:
            if not params_set:
                temp_input.setparams(w.getparams())
                params_set = True
            temp_input.writeframes(w.readframes(w.getnframes()))

#move the cursor back to the beginning of the "file"
temp_file.seek(0)
# Do speech recognition
binary_audio = temp_file.read()
ASR(binary_audio)

note I don't have any .wav files to try this out on. It's up to the wave library to handle the difference between real files and buffered streams properly.