fix(videos): stop offering MPEG and Flash video, which no browser reads

__tests__/mimeCoverage.spec.ts

@@ -51,8 +51,6 @@ const NOT_COVERED_HERE: Record<string, string> = {
 	// so a fixture would only record which browser ran the suite
 	'audio/aacp': 'Chromium reports it cannot play this',
 	'audio/vorbis': 'not a type any encoder writes; ogg carries vorbis',
-	'video/mpeg': 'no engine decodes MPEG-1/2 video',
-	'video/x-flv': 'no engine decodes Flash video',
 	'video/quicktime': 'decoding depends on the codecs inside the container',
 	'video/x-m4v': 'decoding depends on the codecs inside the container',
 	'video/x-matroska': 'aliased to webm; decoding depends on the codecs inside',

__tests__/models.spec.ts

@@ -83,12 +83,10 @@ describe('the custom elements', () => {
 
 describe('videos model', () => {
 	it.each([
-		'video/mpeg',
 		'video/ogg',
 		'video/webm',
 		'video/mp4',
 		'video/x-m4v',
-		'video/x-flv',
 		'video/quicktime',
 	])('enables browser-supported mime %s', async (mime) => {
 		const { registerVideoHandler } = await import('../lib/models/videos.ts')
@@ -97,6 +95,13 @@ describe('videos model', () => {
 		expect(handler.enabled([makeFile({ mime })])).toBe(true)
 	})
 
+	// Neither Chromium nor Firefox reads these: the file downloads instead
+	it.each(['video/mpeg', 'video/x-flv'])('leaves %s to the download', async (mime) => {
+		const { registerVideoHandler } = await import('../lib/models/videos.ts')
+		registerVideoHandler()
+		expect(handlerById('videos').enabled([makeFile({ mime })])).toBe(false)
+	})
+
 	it('enables the aliased mime video/x-matroska (maps to video/webm)', async () => {
 		const { registerVideoHandler } = await import('../lib/models/videos.ts')
 		registerVideoHandler()

lib/models/audios.ts

@@ -10,6 +10,10 @@ import { logger } from '../services/logger.ts'
 import { defineCustomElementOnce } from '../utils/customElements.ts'
 import { t } from '../utils/l10n.ts'
 
+/**
+ * Mimes a file can carry, as the server assigns them or a remote storage
+ * reports them, whose format a browser plays on its own.
+ */
 export const browserSupportedMimes = [
 	'audio/aac',
 	'audio/aacp',

lib/models/videos.ts

@@ -10,13 +10,18 @@ import { logger } from '../services/logger.ts'
 import { defineCustomElementOnce } from '../utils/customElements.ts'
 import { t } from '../utils/l10n.ts'
 
+/**
+ * Mimes a file can carry, as the server assigns them or a remote storage
+ * reports them, whose format a browser plays on its own. Not what
+ * `canPlayType` answers: a QuickTime file holding H.264 plays in Chromium,
+ * which still says it cannot. MPEG-1/2 (`video/mpeg`) and Flash video
+ * (`video/x-flv`) are left out, as neither Chromium nor Firefox reads them.
+ */
 export const browserSupportedMimes = [
-	'video/mpeg',
 	'video/ogg',
 	'video/webm',
 	'video/mp4',
 	'video/x-m4v',
-	'video/x-flv',
 	'video/quicktime',
 ]