audio file format

[satyajitghana]

Hi,

I am trying to record audio in the browser

    const {
        status,
        startRecording,
        stopRecording,
        mediaBlobUrl,
    } = useReactMediaRecorder({
        video: false,
        audio: true,
        blobPropertyBag: {
            type: "audio/wav"
        }
    });

and fetching the file from it

            const audioBlob = await fetch(mediaBlobUrl).then(r => r.blob());

            console.log(audioBlob);

            const audiofile = new File([audioBlob], `${uuidv4()}.wav`, { type: "audio/wav" })

Now i saved this file in disk, and used file audio.wav

and it shows up as as WebM file

$ file b61508fa-9c4e-47fc-bb54-5def7abf9bfc.wav                                                         ─╯
b61508fa-9c4e-47fc-bb54-5def7abf9bfc.wav: WebM

what i need is a wav file ! and it is giving me a WebM file

[gdrbyKo1]

Hi. As far as I can tell, the MediaRecorder API currently doesn't support the audio/wav MIME type. This is unrelated to react-media-recorder, please see w3c/mediacapture-record#198 and the related Firefox and Chromium issues for details.

[satyajitghana]

oh okay, thanks, so probably the mimeType has to be changed in your library ? it's kind of misleading.

also i was wondering, can the bytes in the recorded file be changed to audio/wav, i.e. can we convert audio/webm to audio/wav on the client side ?

[DeltaCircuit]

blobPropertyBag is used only for generating the blobs (after the recording has been completed) inside the media recorder. If you want to use a specific codec to use, you need to pass through mediaRecorderOptions. It'll check for the browser support first and will emit a console.error if there's no support. I'd say not to use the blobPropertyBag if it's not a big-deal. It's just a placeholder for extending the Blob object. Or else we need to keep them in-sync.

That being said, currently this library defaults to video/mp4 / audio/wav while generating the blob, which is kinda incorrect. That needs to be fixed.

For a quick conversion, I'd suggest ffmepg, which has webm --> wav support I believe.

[satyajitghana]

yes thanks, ffmpeg worked ! added it on the server side though, and just realised I could have done it on client side instead.

anyways I was able to convert webm to wav

[liadbelad]

Hey I got the same issue and need to convert to wav file in client side so I can send a wav file to a server.
How can I implement using ffmpeg in the client side please?

[DeltaCircuit]

ffmpeg's usage is pretty straight forward. Download it from here and use it like this:

ffmpeg -i <input_webm> -c:a pcm_f32le .<output>.wav  

[satyajitghana]

@liadbelad not sure if this would work, https://www.npmjs.com/package/ffmpeg

[gdrbyKo1]

@liadbelad for client-side, there's https://github.com/Kagami/ffmpeg.js/ and https://github.com/ffmpegwasm/ffmpeg.wasm
But are you sure you really want to do that? Sending uncompressed audio data over a network will require significantly more bandwidth. It might be a better choice to do the decoding on the receiving side.

[no-1ne]

Ffmpeg is an overkill..try this https://github.com/ai/audio-recorder-polyfill it has wav encoder and mp3 encoder works in iOS world as well

[guest271314]

Hi. As far as I can tell, the MediaRecorder API currently doesn't support the audio/wav

Note, Chrome does support x-matroska;codecs=pcm where the PCM can be extracted, see WebAudio/web-audio-api-v2#63.

Using Web Audio API a MediaStream can be set at MediaStreamAudioSourceNode or at HTMLMediaElement then connected to an AudioWorklet where the Float32Arrays from inputs can be set at an Array, ArrayBuffer, SharedArrayBuffer, or other means of storing data, then WAV headers can be set, e.g., ai/audio-recorder-polyfill#7 (comment).

[vinikatyal]

Does this still not work?

[guest271314]

This is what I used the last time I needed to convert floats to WAV https://github.com/guest271314/webcodecs/blob/main/WavAudioEncoder.js, usage

  const wav = await new WavAudioEncoder({
    sampleRate: 48000,
    numberOfChannels: 1,
    buffers: [new Float32Array(48000)],
  }).encode();

[olegpanchenko]

 useReactMediaRecorder({ mediaRecorderOptions: { mimeType: 'audio/wav' } });

[ramonrovirosa]

In case it helps anyone in the future, I posted my solution using ffmpeg here #101 (comment)

[renny-ren]

blobPropertyBag is used only for generating the blobs (after the recording has been completed) inside the media recorder. If you want to use a specific codec to use, you need to pass through mediaRecorderOptions. It'll check for the browser support first and will emit a console.error if there's no support. I'd say not to use the blobPropertyBag if it's not a big-deal. It's just a placeholder for extending the Blob object. Or else we need to keep them in-sync.

That being said, currently this library defaults to video/mp4 / audio/wav while generating the blob, which is kinda incorrect. That needs to be fixed.

For a quick conversion, I'd suggest ffmepg, which has webm --> wav support I believe.

This should be written in the document 😀 I was thought blobPropertyBag could do the conversion.