Fix SourceRef race conditions, fix "source" and "target" getter returning unused instances, add missing validation, make "getDurationFromMetadata" only exist on tracks, fix examples, expand media player to support live playback, change the signatures of some Input APIs

src/mpeg-ts/mpeg-ts-demuxer.ts

@@ -714,10 +714,6 @@ export class MpegTsDemuxer extends Demuxer {
 		return this.trackBackingEntries;
 	}
 
-	async getDurationFromMetadata(): Promise<number | null> {
-		return null;
-	}
-
 	async getMetadataTags(): Promise<MetadataTags> {
 		return {}; // Nothing for now
 	}