Remove InputTrack.groupId, hide pairing mask, change HLS track merging behavior

src/isobmff/isobmff-demuxer.ts

@@ -39,6 +39,7 @@ import {
 	InputAudioTrackBacking,
 	InputTrack,
 	InputTrackBacking,
+
 	InputVideoTrack,
 	InputVideoTrackBacking,
 } from '../input-track';
@@ -2565,10 +2566,6 @@ abstract class IsobmffTrackBacking implements InputTrackBacking {
 		return this.internalTrack.disposition;
 	}
 
-	getGroupId() {
-		return this.getId();
-	}
-
 	getPairingMask() {
 		return 1n;
 	}