diff --git a/core/modules/media/config/schema/media.schema.yml b/core/modules/media/config/schema/media.schema.yml
index 3adeb77..27e0768 100644
--- a/core/modules/media/config/schema/media.schema.yml
+++ b/core/modules/media/config/schema/media.schema.yml
@@ -52,11 +52,11 @@ media.source.image:
   type: media.source.field_aware
   label: '"Image" media source configuration'
 
-media.source.local_audio:
+media.source.file_audio:
   type: media.source.field_aware
   label: '"Audio" media source configuration'
 
-media.source.local_video:
+media.source.file_video:
   type: media.source.field_aware
   label: '"Video" media source configuration'
 
diff --git a/core/modules/media/src/Plugin/media/Source/LocalAudio.php b/core/modules/media/src/Plugin/media/Source/LocalAudio.php
index 710baaa..0fbb650 100644
--- a/core/modules/media/src/Plugin/media/Source/LocalAudio.php
+++ b/core/modules/media/src/Plugin/media/Source/LocalAudio.php
@@ -11,9 +11,9 @@
  * @see \Drupal\file\FileInterface
  *
  * @MediaSource(
- *   id = "local_audio",
+ *   id = "file_audio",
  *   label = @Translation("Audio (local)"),
- *   description = @Translation("Use local audios for reusable media."),
+ *   description = @Translation("Use audio files for reusable media."),
  *   allowed_field_types = {"file"},
  *   default_thumbnail_filename = "audio.png"
  * )
@@ -24,7 +24,7 @@ class LocalAudio extends File {
    * {@inheritdoc}
    */
   public function createSourceField(MediaTypeInterface $type) {
-    return parent::createSourceField($type)->set('settings', ['file_extensions' => 'mp3 ogg wav wma aiff aac']);
+    return parent::createSourceField($type)->set('settings', ['file_extensions' => 'mp3 ogg wav wma aiff aac m4a']);
   }
 
   /**
diff --git a/core/modules/media/src/Plugin/media/Source/LocalVideo.php b/core/modules/media/src/Plugin/media/Source/LocalVideo.php
index cf40b86..a285d3c 100644
--- a/core/modules/media/src/Plugin/media/Source/LocalVideo.php
+++ b/core/modules/media/src/Plugin/media/Source/LocalVideo.php
@@ -11,9 +11,9 @@
  * @see \Drupal\file\FileInterface
  *
  * @MediaSource(
- *   id = "local_video",
+ *   id = "file_video",
  *   label = @Translation("Video (local)"),
- *   description = @Translation("Use local videos for reusable media."),
+ *   description = @Translation("Use video files for reusable media."),
  *   allowed_field_types = {"file"},
  *   default_thumbnail_filename = "video.png"
  * )
diff --git a/core/modules/media/tests/src/FunctionalJavascript/MediaSourceAudioVideoTest.php b/core/modules/media/tests/src/FunctionalJavascript/MediaSourceAudioVideoTest.php
index 53b3001..3b53952 100644
--- a/core/modules/media/tests/src/FunctionalJavascript/MediaSourceAudioVideoTest.php
+++ b/core/modules/media/tests/src/FunctionalJavascript/MediaSourceAudioVideoTest.php
@@ -17,7 +17,7 @@ class MediaSourceAudioVideoTest extends MediaSourceTestBase {
    * Check the Local Audio source functionality.
    */
   public function testAudioTypeCreation() {
-    $source_id = 'local_audio';
+    $source_id = 'file_audio';
     $type_name = 'audio_type';
     $field_name = 'field_media_' . $source_id;
     $this->doTestCreateMediaType($type_name, $source_id);
@@ -27,7 +27,7 @@ public function testAudioTypeCreation() {
     $this->assertNotNull($storage);
     $field = FieldConfig::load("media.$type_name.$field_name");
     $this->assertNotNull($field);
-    $this->assertSame('mp3 ogg wav wma aiff aac', FieldConfig::load("media.$type_name.$field_name")->get('settings')['file_extensions']);
+    $this->assertSame('mp3 ogg wav wma aiff aac m4a', FieldConfig::load("media.$type_name.$field_name")->get('settings')['file_extensions']);
 
     // Check that the display holds the correct formatter configuration.
     $display = EntityViewDisplay::load("media.$type_name.default");
@@ -40,7 +40,7 @@ public function testAudioTypeCreation() {
    * Check the Local Video source functionality.
    */
   public function testVideoTypeCreation() {
-    $source_id = 'local_video';
+    $source_id = 'file_video';
     $type_name = 'video_type';
     $field_name = 'field_media_' . $source_id;
     $this->doTestCreateMediaType($type_name, $source_id);