Add InputTrack.number

src/matroska/matroska-demuxer.ts

@@ -1859,6 +1859,27 @@ abstract class MatroskaTrackBacking implements InputTrackBacking {
 		return this.internalTrack.id;
 	}
 
+	getNumber() {
+		const demuxer = this.internalTrack.demuxer;
+		const inputTrack = this.internalTrack.inputTrack!;
+		const trackType = inputTrack.type;
+
+		let number = 0;
+		for (const segment of demuxer.segments) {
+			for (const track of segment.tracks) {
+				if (track.inputTrack!.type === trackType) {
+					number++;
+				}
+
+				if (track === this.internalTrack) {
+					break;
+				}
+			}
+		}
+
+		return number;
+	}
+
 	getCodec(): MediaCodec | null {
 		throw new Error('Not implemented on base class.');
 	}