How to convert a numpy array waveform into a wav file-like object?

I want to convert a numpy array waveform into a wav-like object so that I can upload it to S3 without having to save the waveform to file locally. Imagine I have a numpy array waveform, y,

y, sr = librosa.load('something.wav', sr = 44100)

How can I convert this numpy array, y into a wav file-like object to upload to S3 using boto3‘s upload_fileobj method?

According to the boto3 docs, the file-like object must have the properties:

A file-like object to upload. At a minimum, it must implement the read method, and must return bytes.

This is how I would like to upload the file-like object:

import boto3
s3 = boto3.resource('s3')
bucket = s3.Bucket('mybucket')

# with open('filename', 'rb') as data:
#    bucket.upload_fileobj(data, 'mykey')
bucket.upload_fileobj(wav_object, 'something.wav')

TLDR:

I want a function that converts a numpy array into a wav-like object that implements the read method and returns bytes.

Answer

You can try like this:

import io 
from scipy.io.wavfile import write
import boto3

bytes_wav = bytes()
wav_object = io.BytesIO(bytes_wav)
write(wav_object, sr, y) # y is your numpy array


s3 = boto3.resource('s3')
bucket = s3.Bucket('mybucket')

bucket.upload_fileobj(wav_object, 'something.wav')

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Answer