Make default keyFrameInterval 2 seconds to align with default HLS segment duration

test/browser/hls-output.test.ts

@@ -0,0 +1,60 @@
+import { expect, test } from 'vitest';
+import { Output } from '../../src/output.js';
+import { HlsOutputFormat, MpegTsOutputFormat } from '../../src/output-format.js';
+import { BufferTarget, PathedTarget } from '../../src/target.js';
+import { CanvasSource } from '../../src/media-source.js';
+import { QUALITY_HIGH } from '../../src/encode.js';
+
+test('HLS output, key frames aligning with segment boundaries by default', async () => {
+	let playlistText: string | null = null;
+
+	const output = new Output({
+		format: new HlsOutputFormat({
+			segmentFormat: new MpegTsOutputFormat(),
+			onPlaylist: (text) => { playlistText = text; },
+		}),
+		target: new PathedTarget('', () => new BufferTarget()),
+	});
+
+	const canvas = new OffscreenCanvas(640, 480);
+	const ctx = canvas.getContext('2d')!;
+	ctx.fillStyle = '#ff0000';
+	ctx.fillRect(0, 0, canvas.width, canvas.height);
+
+	const videoSource = new CanvasSource(canvas, {
+		codec: 'avc',
+		bitrate: QUALITY_HIGH,
+	});
+	output.addVideoTrack(videoSource);
+
+	await output.start();
+
+	const fps = 2;
+	const frameDuration = 1 / fps;
+	const totalFrames = 10 * fps;
+	for (let i = 0; i < totalFrames; i++) {
+		await videoSource.add(i * frameDuration, frameDuration);
+	}
+
+	await output.finalize();
+
+	expect(playlistText).toBe(`#EXTM3U
+#EXT-X-VERSION:3
+#EXT-X-PLAYLIST-TYPE:VOD
+#EXT-X-TARGETDURATION:2
+#EXT-X-INDEPENDENT-SEGMENTS
+
+#EXTINF:2,
+segment-1-1.ts
+#EXTINF:2,
+segment-1-2.ts
+#EXTINF:2,
+segment-1-3.ts
+#EXTINF:2,
+segment-1-4.ts
+#EXTINF:2,
+segment-1-5.ts
+
+#EXT-X-ENDLIST
+`);
+});