Add isMSESupported check

Add named exports for and expose statically: `isSupported`, `isMSESupported`, and `getMediaSource`

api-extractor/report/hls.js.api.md

@@ -1592,6 +1592,8 @@ class Hls implements HlsEventEmitter {
     // Warning: (ae-setter-with-docs) The doc comment for the property "firstLevel" must appear on the getter, not the setter.
     set firstLevel(newLevel: number);
     get forceStartLoad(): boolean;
+    static getMediaSource(): typeof MediaSource | undefined;
+    static isMSESupported(): boolean;
     static isSupported(): boolean;
     get latency(): number;
     // (undocumented)

docs/API.md

@@ -190,17 +190,28 @@ First include `https://cdn.jsdelivr.net/npm/hls.js@1` (or `/hls.js` for unminifi
 <script src="//cdn.jsdelivr.net/npm/hls.js@1"></script>
 ```
 
-Invoke the following static method: `Hls.isSupported()` to check whether your browser is supporting [MediaSource Extensions](http://w3c.github.io/media-source/).
+Invoke the following static method: `Hls.isSupported()` to check whether your browser supports [MediaSource Extensions](http://w3c.github.io/media-source/) with any baseline codecs.
 
 ```html
 <script src="https://cdn.jsdelivr.net/npm/hls.js@1"></script>
 <script>
   if (Hls.isSupported()) {
-    console.log('hello hls.js!');
+    console.log('Hello HLS.js!');
   }
 </script>
 ```
 
+If you want to test for MSE support without testing for baseline codecs, use `isMSESupported`:
+
+```js
+if (
+  Hls.isMSESupported() &&
+  Hls.getMediaSource().isTypeSupported('video/mp4;codecs="av01.0.01M.08"')
+) {
+  console.log('Hello AV1 playback! AVC who?');
+}
+```
+
 ### Second step: instantiate Hls object and bind it to `<video>` element
 
 Let's

src/exports-named.ts

@@ -55,3 +55,5 @@ export {
   ErrorActionFlags,
 } from './controller/error-controller';
 export { AttrList } from './utils/attr-list';
+export { isSupported, isMSESupported } from './is-supported';
+export { getMediaSource } from './utils/mediasource-helper';

src/hls.ts

@@ -6,7 +6,8 @@ import LevelController from './controller/level-controller';
 import { FragmentTracker } from './controller/fragment-tracker';
 import KeyLoader from './loader/key-loader';
 import StreamController from './controller/stream-controller';
-import { isSupported } from './is-supported';
+import { isMSESupported, isSupported } from './is-supported';
+import { getMediaSource } from './utils/mediasource-helper';
 import { logger, enableLogs } from './utils/logger';
 import { enableStreamingMode, hlsDefaultConfig, mergeConfig } from './config';
 import { EventEmitter } from 'eventemitter3';
@@ -87,10 +88,24 @@ export default class Hls implements HlsEventEmitter {
   /**
    * Check if the required MediaSource Extensions are available.
    */
+  static isMSESupported(): boolean {
+    return isMSESupported();
+  }
+
+  /**
+   * Check if MediaSource Extensions are available and isTypeSupported checks pass for any baseline codecs.
+   */
   static isSupported(): boolean {
     return isSupported();
   }
 
+  /**
+   * Get the MediaSource global used for MSE playback (ManagedMediaSource, MediaSource, or WebKitMediaSource).
+   */
+  static getMediaSource(): typeof MediaSource | undefined {
+    return getMediaSource();
+  }
+
   static get Events(): typeof Events {
     return Events;
   }

src/is-supported.ts

@@ -1,59 +1,50 @@
 import { getMediaSource } from './utils/mediasource-helper';
-import { getCodecCompatibleName, mimeTypeForCodec } from './utils/codecs';
+import { mimeTypeForCodec } from './utils/codecs';
 import type { ExtendedSourceBuffer } from './types/buffer';
 
 function getSourceBuffer(): typeof self.SourceBuffer {
   return self.SourceBuffer || (self as any).WebKitSourceBuffer;
 }
 
-export function isSupported(): boolean {
+export function isMSESupported(): boolean {
   const mediaSource = getMediaSource();
   if (!mediaSource) {
     return false;
   }
-  const sourceBuffer = getSourceBuffer();
 
   // if SourceBuffer is exposed ensure its API is valid
   // Older browsers do not expose SourceBuffer globally so checking SourceBuffer.prototype is impossible
-  const sourceBufferValidAPI =
+  const sourceBuffer = getSourceBuffer();
+  return (
     !sourceBuffer ||
     (sourceBuffer.prototype &&
       typeof sourceBuffer.prototype.appendBuffer === 'function' &&
-      typeof sourceBuffer.prototype.remove === 'function');
-  if (!sourceBufferValidAPI) {
+      typeof sourceBuffer.prototype.remove === 'function')
+  );
+}
+
+export function isSupported(): boolean {
+  if (!isMSESupported()) {
     return false;
   }
 
+  const mediaSource = getMediaSource();
   return (
-    !!mediaSource &&
-    typeof mediaSource.isTypeSupported === 'function' &&
-    ([
-      'avc1.42E01E,mp4a.40.2',
-      'hvc1.1.6.L123.B0',
-      'av01.0.01M.08',
-      'vp09.00.50.08',
-    ].some((codecsForVideoContainer) =>
-      isMimeTypeSupported(
-        mediaSource,
-        mimeTypeForCodec(codecsForVideoContainer, 'video'),
-      ),
+    typeof mediaSource?.isTypeSupported === 'function' &&
+    (['avc1.42E01E,mp4a.40.2', 'av01.0.01M.08', 'vp09.00.50.08'].some(
+      (codecsForVideoContainer) =>
+        mediaSource.isTypeSupported(
+          mimeTypeForCodec(codecsForVideoContainer, 'video'),
+        ),
     ) ||
       ['mp4a.40.2', 'fLaC'].some((codecForAudioContainer) =>
-        isMimeTypeSupported(
-          mediaSource,
+        mediaSource.isTypeSupported(
           mimeTypeForCodec(codecForAudioContainer, 'audio'),
         ),
       ))
   );
 }
 
-function isMimeTypeSupported(
-  mediaSource: typeof MediaSource,
-  mimeType: string,
-): boolean {
-  return mediaSource.isTypeSupported(mimeType);
-}
-
 export function changeTypeSupported(): boolean {
   const sourceBuffer = getSourceBuffer();
   return (