I used RecordRTC to record two 1-minute long videos as follows:

1. Recorded on iPhone 11 (iOS 17.4.1) / file size = 77 mb
2. Recorded on iPhone 8+ (iOS 16.7.7) / file size = 8 mb

I used the below code to initialize the videoRecorder:

this.audioRecorder = new RecordRTC(this.stream, {
      type: 'audio',
      mimeType: 'audio/webm',
     
    });
    this.videoRecorder = new RecordRTC(this.stream, {
      type: 'video',
      mimeType: 'video/webm',
      bitsPerSecond: 1000000 
                     
    });

Why is the file size is different in iOS 17?