Preview uploaded video in Angular

I am trying to upload a video and preview it in the webpage but the video being uploaded is just not playing despite being uploaded correctly.

Here are the steps I am doing :

1. Upload a file in UI
2. Read the file using readAsDataURL() method of fileReader instance.
3. Uploaded file is read and converted to a base64 format string.
4. Convert base64 to a binary data
5. Create a blob with which contains the file data in converted binary format.
6. Create a URL for above created blob.
7. Provide this URL as source for my video tag in HTML

Here is the code of my HTML file :

<input type="file" (change)="trigger($event)">
<video width="400" height="400" controls *ngIf="videoSource">
    <source [src]="videoSource" type="video/quicktime">
    Your browser does not support the video tag.
</video>

Here is the code of TS file in Angular :

 trigger(uploadedFileEvent){
        const videoPlayer = document.getElementById('videoPlayer');
        let fileReader = new FileReader();
        if(uploadedFileEvent.target.files[0]) fileReader.readAsDataURL(uploadedFileEvent.target.files[0]);

        new Promise( (resolve,reject) => {
            fileReader.onload = function(event) {
                const source = event.target.result;
                resolve (source)
            }
        }).then(source => {
            let videoSource = source as string;
            this.videoSource = atob(videoSource.replace(/^[^,]*,/ ,''));       // convert to binary data
            let view = new Uint8Array(videoSource.length);
            for (let i = 0; i < videoSource.length; i++) {
                view[i] = videoSource.charCodeAt(i);
            }
            const videoBlob = new Blob([view] , {type : 'video/quicktime'});
            this.videoSource = URL.createObjectURL(videoBlob);
        })
    } 

I have checked around in all places. The approach seems to be correct but I don’t seem to understand why this code is failing.
Please let me know how I can make this solution work. In case there is any alternative solution anybody is aware of please post them. In case anybody finds this questions as repetitive I apologise but I was unable to solve despite checking online resources.

Thanks for the help!