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

test/node/hls-input.test.ts

@@ -13,11 +13,14 @@ test.concurrent('Big Buck Bunny', { timeout: 15_000 }, async () => {
 	let sourceCount = 0;
 	input.on('source', () => sourceCount++);
 
+	let rootReadCount = 0;
+	input.source.on('read', () => rootReadCount++);
+
 	expect(await input.getFormat()).toBeInstanceOf(HlsInputFormat);
 	expect(await input.getFormat()).toBe(HLS);
-	expect(await input.getDurationFromMetadata()).toBe(null); // Since it's a master playlist!
 
 	expect(sourceCount).toBe(1);
+	expect(rootReadCount).toBeGreaterThan(0);
 
 	// Test descriptors (unhydrated metadata from master playlist)
 	const descriptors = await input.getTrackDescriptors();
@@ -211,6 +214,8 @@ test.concurrent('Big Buck Bunny', { timeout: 15_000 }, async () => {
 	// Since they're the highest-bitrate option
 	expect(primaryVideoTrack).toBe(videoTracks[4]);
 	expect(primaryAudioTrack).toBe(audioTracks[4]);
+
+	expect(await input.getDurationFromMetadata()).not.toBe(null);
 });
 
 test.concurrent('Single-variant Big Buck Bunny', { timeout: 15_000 }, async () => {

test/node/hls-output.test.ts

@@ -1817,7 +1817,7 @@ segment-1-1.ts
 	);
 });
 
-test('onSegment, onPlaylist, onMaster events', async () => {
+test('write, onSegment, onPlaylist, onMaster events', async () => {
 	const onSegment = vi.fn();
 	const onPlaylist = vi.fn();
 	const onMaster = vi.fn();
@@ -1832,6 +1832,9 @@ test('onSegment, onPlaylist, onMaster events', async () => {
 		target: new PathedTarget('', () => new BufferTarget()),
 	});
 
+	let targetWrites = 0;
+	output.target.on('write', () => targetWrites++);
+
 	const source = videoSource();
 	output.addVideoTrack(source);
 
@@ -1858,6 +1861,8 @@ test('onSegment, onPlaylist, onMaster events', async () => {
 
 	await output.finalize();
 
+	expect(targetWrites).toBeGreaterThan(0);
+
 	// Second segment finalized on close
 	expect(onSegment).toHaveBeenCalledTimes(2);
 	expect(onSegment.mock.calls[1]![1]).toEqual(expect.objectContaining({ n: 2 }));