Is there a way to only get the last chunk recorded when timeSlice is used?

[Desi DImitrova]

I have the following code which slices the recording into 1-minute chunks:

this.recorder = new RecordRTC(this.stream, {
        type: 'audio',
        mimeType: 'audio/wav', 
        recorderType: StereoAudioRecorder,
        desiredSampRate: 16000,
        numberOfAudioChannels: 1, 
        bufferSize: 16384,
        audioBitsPerSecond: 128000,
        disableLogs: true,
        timeSlice: 60000,
        ondataavailable: (blob: Blob) => {
          // do something
        }
});

if the recorder stops when we only have 30 seconds of audio data, is there a way to get that last 30-second recording?

[Damiaan]

Yes, you can access (individual) slices created by timeSlice using the internalRecorder .

say you init the recorder with the above code:

this.recorder = new RecordRTC(this.stream, {
        type: 'audio',
        mimeType: 'audio/wav', 
        recorderType: StereoAudioRecorder,
        desiredSampRate: 16000,
        numberOfAudioChannels: 1, 
        bufferSize: 16384,
        audioBitsPerSecond: 128000,
        disableLogs: true,
        timeSlice: 60000,
});

Then, you can access the internal array of sliced blobs and retrieve any (read: the last) chunk.

const internal = this.recorder.getInternalRecorder();
if (internal && internal.getArrayOfBlobs) {
        const blobArray = internal.getArrayOfBlobs(); //returns array with all slices
        const lastBlob = blobArray[blobArray.length - 1]; //get the last blob
        const lastBlobURL = URL.createObjectURL(lastBlob)); //do something with is, such as creating an url for it

        // you can also create a new blob using (for instance) all previous recorded blobs:
         const bigBlob = new Blob(internal.getArrayOfBlobs(), {
                type: "audio",
          });
         const bigBlobURL = URL.createObjectURL(bigBlob)); //do something with is, such as creating an url for it
        }

see also:
Mozilla API Reference
This example by RecordRTC

[Damiaan]

Small sidenote

you write:

if the recorder stops when we only have 30 seconds of audio data, is there a way to get that last 30-second recording?

If you stop the recording before the first slice is made (so any recording less than 1 minute in your example) you can access this blob on the normal way! As can be read in the documentation:

When MediaRecorder.stop() is called, all media data which has been captured since recording began or the last time a dataavailable event occurred is delivered in a Blob; after this, capturing ends.

[Desi DImitrova]

Thank you for the information!!