How to stream Base64 data into a video

I am trying to get a video to load from a stream. I would like to be able to "play" the video even if the entire video has not "downloaded" yet. The base64 data is coming in as a stream of buffer chunks.

const videoTag = document.getElementById('videoTag');
const mimeCodec = 'video/mp4; codecs="avc1.42E01E, mp4a.40.2"';
const mediaSource = new MediaSource();

videoTag.src = URL.createObjectURL(mediaSource);

await new Promise((resolve, reject) => {
    mediaSource.addEventListener('sourceopen', function (_) {
        resolve();
    });
});

const sourceBuffer = mediaSource.addSourceBuffer(mimeCodec);


for await (const chunk of ipfsNode.cat(CID)) {//Chunk is coming in as an array buffer
    sourceBuffer.appendBuffer(chunk);
}

sourceBuffer.addEventListener('updateend', async function (_) {
    mediaSource.endOfStream();
    $('#videoTag')[0].load();
});

I've tried using new MediaSource() and sourceBuffer.appendBuffer(chunk); to push new downloaded chunks to the video, but not only does the video not ever play, the method I am using requires that the entire video downloads before it can play.

How can I get my chunks of base64 data into a video?

EDIT (in response to comments): Regardless of whether or not I use a String or binary steam, I am a little confused on how I get a stream into a video.

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