Fix incorrectly-written video rotation metadata even when rotation is baked into the video (fixes #329)

test/browser/conversion.test.ts

@@ -0,0 +1,49 @@
+import { ALL_FORMATS } from '../../src/input-format.js';
+import { Input } from '../../src/input.js';
+import { Mp4OutputFormat } from '../../src/output-format.js';
+import { Output } from '../../src/output.js';
+import { BufferSource, UrlSource } from '../../src/source.js';
+import { expect, test } from 'vitest';
+import { BufferTarget } from '../../src/target.js';
+import { Conversion } from '../../src/conversion.js';
+import { assert } from '../../src/misc.js';
+
+test('Rotation is baked-in when rerendering', async () => {
+	using input = new Input({
+		source: new UrlSource('/rotate-buck-bunny.mp4'),
+		formats: ALL_FORMATS,
+	});
+
+	const ogTrack = await input.getPrimaryVideoTrack();
+	assert(ogTrack);
+
+	expect(ogTrack.rotation).toBe(90);
+	expect(ogTrack.codedWidth).toBe(1920);
+	expect(ogTrack.codedHeight).toBe(1080);
+	expect(ogTrack.displayWidth).toBe(1080);
+	expect(ogTrack.displayHeight).toBe(1920);
+
+	const output = new Output({
+		format: new Mp4OutputFormat(),
+		target: new BufferTarget(),
+	});
+
+	const conversion = await Conversion.init({ input, output, video: {
+		width: 320,
+	} });
+	await conversion.execute();
+
+	using newInput = new Input({
+		source: new BufferSource(output.target.buffer!),
+		formats: ALL_FORMATS,
+	});
+
+	const track = await newInput.getPrimaryVideoTrack();
+	assert(track);
+
+	expect(track.codedWidth).toBe(320);
+	expect(track.codedHeight).toBe(570);
+	expect(track.displayWidth).toBe(320);
+	expect(track.displayHeight).toBe(570);
+	expect(track.rotation).toBe(0);
+});