Convert audio from url to base64 in nodejs?

Question

I want to send a voice clip to facebook messenger and have it translated to text using Google Cloud Speech to text. However, facebook messenger format set the url to the file, and I have no idea to convert it to base 64. If it's an image like .png and .jpg, it's fine, there are packages for that. But I am trying to convert audio like .mp3 and .m4a files. Is there any tool for that to work with nodejs.

I would prefer not to save the audio file as a local file, beause I am deploying a server using Google App Engine, and doing so will just make the matter super complicated.

score 1 · Answer 1 · answered Jun 06 '19 at 19:50

I got what I need from here. While the question is about image, the code seems to work fine sound.

const getBase64 = async (url) => {
    try {
        var result =  await  axios
            .get(url, {
                responseType: 'arraybuffer'
            })
            .then(response =>  new Buffer.from(response.data, 'binary').toString('base64'))


        return { data: result}
    }catch (e) {
        return {error: e};
    }
}

score 1 · Answer 2 · answered May 21 '21 at 18:06

1

import mineType from 'mime-types';

const getBase64 = async (url) => {
  try {
    const response = await axios.get(url, { responseType: 'arraybuffer' });
    const base64 = Buffer.from(response.data, 'binary').toString('base64');
    return "data:" + mineType.lookup(url) + ";base64," + base64;
  }catch (e) {
    return "";
  }
}

answered May 21 '21 at 18:06

Turkyden

11
3

1

Please don't post only code as answer, but also provide an explanation what your code does and how it solves the problem of the question. Answers with an explanation are usually more helpful and of better quality, and are more likely to attract upvotes. – Tyler2P May 21 '21 at 18:40

score 0 · Answer 3 · answered Jun 05 '19 at 19:43

You can look into the FileReader API and possibly the AudioData API - between those two you should have everything you need. With sending audio files over the wire, you don't transfer them as base64. I believe it is either binary or blob iirc.

You can use the FileReader api - read in your audio file using FileReader.readAsArrayBuffer() which will convert your file into a mapped array. From there, you can turn it into a blob object and push it wherever you need.

             var uInt8Array     = new Uint8Array(mappedArray);
             var arrayBuffer    = uInt8Array.buffer;
             var blob           = new Blob([arrayBuffer]);
             var url            = URL.createObjectURL(blob);

I use this same approach when working with Amazon's Polly to turn text into speech

Convert audio from url to base64 in nodejs?

3 Answers3