Reject opus decoding without description when there's more than 2 cha…

…nnels.

Differential Revision: https://phabricator.services.mozilla.com/D220431

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1915143
gecko-commit: 5e3767e9fcca6448d4c1161db2623405369f7f7f
gecko-reviewers: chunmin

webcodecs/audio-decoder.https.any.js

@@ -67,41 +67,7 @@ const invalidConfigs = [
       codec: 'opus',
       sampleRate: 8000,
       numberOfChannels: 1,
-      description: detachedArrayBuffer
-    },
-  },
-  {
-    comment: 'Vorbis without description',
-    config: {
-      codec: 'vorbis',
-      sampleRate: 48000,
-      numberOfChannels: 2,
-    },
-  },
-  {
-    comment: 'Vorbis with empty description',
-    config: {
-      codec: 'vorbis',
-      sampleRate: 48000,
-      numberOfChannels: 2,
-      description: emptyArrayBuffer,
-    },
-  },
-  {
-    comment: 'Flac without description',
-    config: {
-      codec: 'flac',
-      sampleRate: 48000,
-      numberOfChannels: 2,
-    },
-  },
-  {
-    comment: 'Flac with empty description',
-    config: {
-      codec: 'flac',
-      sampleRate: 48000,
-      numberOfChannels: 2,
-      description: emptyArrayBuffer,
+      description: detachedArrayBuffer,
     },
   },
 ];
@@ -180,6 +146,27 @@ const validButUnsupportedConfigs = [
   },
 ];
 
+// Those configurations are supported, but attempting to configure an
+// AudioDecoder will fail, because `description` is invalid for this particular
+// codec
+var supportedButErrorOnConfiguration = [
+  {
+    comment: 'Opus with more than two channels and without description',
+    config: {
+      codec: 'opus',
+      sampleRate: '48000',
+      numberOfChannels: 3,
+    },
+  },
+  {
+    comment: 'Opus with more than two channels and with a description that is too short',
+    config: {
+      codec: 'opus',
+      sampleRate: '48000',
+      numberOfChannels: 3,
+      description: new Uint8Array(9), // at least 10 bytes are required for multichannel
+    },
+  },
 validButUnsupportedConfigs.forEach(entry => {
   promise_test(
       t => {
@@ -191,10 +178,14 @@ validButUnsupportedConfigs.forEach(entry => {
           entry.comment);
 });
 
-validButUnsupportedConfigs.forEach(entry => {
+var shouldError = validButUnsupportedConfigs.concat(supportedButErrorOnConfiguration);
+
+shouldError.forEach(entry => {
   promise_test(
       t => {
         let isErrorCallbackCalled = false;
+        let supported = AudioDecoder.isConfigSupported(entry.config);
+        assert_implements_optional(supported, entry.config.codec + ' unsupported');
         let codec = new AudioDecoder({
           output: t.unreached_func('unexpected output'),
           error: t.step_func_done(e => {