diff --git a/lib/media/media_source_engine.js b/lib/media/media_source_engine.js
index a131015a61..24dfadfda1 100644
--- a/lib/media/media_source_engine.js
+++ b/lib/media/media_source_engine.js
@@ -1052,7 +1052,7 @@ shaka.media.MediaSourceEngine = class {
       return;
     }
     const hasChangedCodecs =
-        await this.determineCodecSwitch_(contentType, stream, streamsByType);
+        await this.codecSwitchIfNecessary_(contentType, stream, streamsByType);
 
     await Promise.all([
       // Queue an abort() to help MSE splice together overlapping segments.
@@ -1360,7 +1360,7 @@ shaka.media.MediaSourceEngine = class {
    * Enqueue an operation which must block all other operations on all
    * SourceBuffers.
    *
-   * @param {function()} run
+   * @param {function():(Promise|undefined)} run
    * @return {!Promise}
    * @private
    */
@@ -1669,15 +1669,17 @@ shaka.media.MediaSourceEngine = class {
   }
 
   /**
-   * Codec switch if necessary
+   * Codec switch if necessary, this will not resolve until the codec
+   * switch is over.
    * @param {shaka.util.ManifestParserUtils.ContentType} contentType
    * @param {shaka.extern.Stream} stream
    * @param {!Map.<shaka.util.ManifestParserUtils.ContentType,
    *               shaka.extern.Stream>} streamsByType
-   * @return {!Promise.<boolean>}
+   * @return {!Promise.<boolean>} true if there was a codec switch,
+   *                              false otherwise.
    * @private
    */
-  async determineCodecSwitch_(contentType, stream, streamsByType) {
+  async codecSwitchIfNecessary_(contentType, stream, streamsByType) {
     const MimeUtils = shaka.util.MimeUtils;
     const currentCodec = MimeUtils.getCodecBase(
         MimeUtils.getCodecs(this.sourceBufferTypes_[contentType]));
diff --git a/lib/media/streaming_engine.js b/lib/media/streaming_engine.js
index f06cafa578..822481a704 100644
--- a/lib/media/streaming_engine.js
+++ b/lib/media/streaming_engine.js
@@ -2501,9 +2501,9 @@ shaka.media.StreamingEngine.PlayerInterface;
  *   The last append window start given to MediaSourceEngine for this type.
  * @property {?number} lastAppendWindowEnd
  *   The last append window end given to MediaSourceEngine for this type.
- * @property {?number} lastCodecs
+ * @property {?string} lastCodecs
  *   The last append codecs given to MediaSourceEngine for this type.
- * @property {?number} lastMimeType
+ * @property {?string} lastMimeType
  *   The last append mime type given to MediaSourceEngine for this type.
  * @property {?shaka.extern.Stream} restoreStreamAfterTrickPlay
  *   The Stream to restore after trick play mode is turned off.