diff --git a/library/core/src/main/java/com/google/android/exoplayer2/text/SubtitleDecoderFactory.java b/library/core/src/main/java/com/google/android/exoplayer2/text/SubtitleDecoderFactory.java
index e59a7489bb..bd652c6586 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/text/SubtitleDecoderFactory.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/text/SubtitleDecoderFactory.java
@@ -91,15 +91,11 @@ public interface SubtitleDecoderFactory {
 
         @Override
         public SubtitleDecoder createDecoder(Format format) {
-          @Nullable String sampleMimeType = format.sampleMimeType;
-          if (sampleMimeType != null) {
-            switch (sampleMimeType) {
+          @Nullable String mimeType = format.sampleMimeType;
+          if (mimeType != null) {
+            switch (mimeType) {
               case MimeTypes.TEXT_VTT:
-                if (MimeTypes.APPLICATION_MP4.equals(format.containerMimeType)) {
-                  return new Mp4WebvttDecoder();
-                } else {
-                  return new WebvttDecoder();
-                }
+                return new WebvttDecoder();
               case MimeTypes.TEXT_SSA:
                 return new SsaDecoder(format.initializationData);
               case MimeTypes.APPLICATION_MP4VTT:
@@ -113,7 +109,7 @@ public interface SubtitleDecoderFactory {
               case MimeTypes.APPLICATION_CEA608:
               case MimeTypes.APPLICATION_MP4CEA608:
                 return new Cea608Decoder(
-                    sampleMimeType,
+                    mimeType,
                     format.accessibilityChannel,
                     Cea608Decoder.MIN_DATA_CHANNEL_TIMEOUT_MS);
               case MimeTypes.APPLICATION_CEA708:
@@ -127,7 +123,7 @@ public interface SubtitleDecoderFactory {
             }
           }
           throw new IllegalArgumentException(
-              "Attempted to create decoder for unsupported MIME type: " + sampleMimeType);
+              "Attempted to create decoder for unsupported MIME type: " + mimeType);
         }
       };
 }
diff --git a/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/DashManifestParser.java b/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/DashManifestParser.java
index 8015c139b4..83e6556fe1 100644
--- a/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/DashManifestParser.java
+++ b/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/DashManifestParser.java
@@ -1363,7 +1363,8 @@ public class DashManifestParser extends DefaultHandler
       // All other text types are raw formats.
       return containerMimeType;
     } else if (MimeTypes.APPLICATION_MP4.equals(containerMimeType)) {
-      return MimeTypes.getMediaMimeType(codecs);
+      @Nullable String mimeType = MimeTypes.getMediaMimeType(codecs);
+      return MimeTypes.TEXT_VTT.equals(mimeType) ? MimeTypes.APPLICATION_MP4VTT : mimeType;
     }
     return null;
   }