diff --git a/library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadRequest.java b/library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadRequest.java
index 5acefd6f93..7ff43ceacd 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadRequest.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadRequest.java
@@ -52,7 +52,10 @@ public final class DownloadRequest implements Parcelable {
   public final Uri uri;
   /** Stream keys to be downloaded. If empty, all streams will be downloaded. */
   public final List<StreamKey> streamKeys;
-  /** Custom key for cache indexing, or null. */
+  /**
+   * Custom key for cache indexing, or null. Must be null for DASH, HLS and SmoothStreaming
+   * downloads.
+   */
   @Nullable public final String customCacheKey;
   /** Application defined data associated with the download. May be empty. */
   public final byte[] data;
@@ -72,6 +75,10 @@ public final class DownloadRequest implements Parcelable {
       List<StreamKey> streamKeys,
       @Nullable String customCacheKey,
       @Nullable byte[] data) {
+    if (TYPE_DASH.equals(type) || TYPE_HLS.equals(type) || TYPE_SS.equals(type)) {
+      Assertions.checkArgument(
+          customCacheKey == null, "customCacheKey must be null for type: " + type);
+    }
     this.id = id;
     this.type = type;
     this.uri = uri;
diff --git a/library/core/src/test/assets/offline/action_file_for_download_index_upgrade.exi b/library/core/src/test/assets/offline/action_file_for_download_index_upgrade.exi
index 888ba4af44..0bf49b133a 100644
Binary files a/library/core/src/test/assets/offline/action_file_for_download_index_upgrade.exi and b/library/core/src/test/assets/offline/action_file_for_download_index_upgrade.exi differ
diff --git a/library/core/src/test/java/com/google/android/exoplayer2/offline/ActionFileUpgradeUtilTest.java b/library/core/src/test/java/com/google/android/exoplayer2/offline/ActionFileUpgradeUtilTest.java
index 5153b53839..96b8ff21bc 100644
--- a/library/core/src/test/java/com/google/android/exoplayer2/offline/ActionFileUpgradeUtilTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/offline/ActionFileUpgradeUtilTest.java
@@ -15,7 +15,7 @@
  */
 package com.google.android.exoplayer2.offline;
 
-import static com.google.android.exoplayer2.offline.DownloadRequest.TYPE_DASH;
+import static com.google.android.exoplayer2.offline.DownloadRequest.TYPE_PROGRESSIVE;
 import static com.google.common.truth.Truth.assertThat;
 
 import android.net.Uri;
@@ -73,7 +73,7 @@ public class ActionFileUpgradeUtilTest {
     DownloadRequest expectedRequest1 =
         new DownloadRequest(
             "key123",
-            TYPE_DASH,
+            /* type= */ "test",
             Uri.parse("https://www.test.com/download1"),
             asList(expectedStreamKey1),
             /* customCacheKey= */ "key123",
@@ -81,7 +81,7 @@ public class ActionFileUpgradeUtilTest {
     DownloadRequest expectedRequest2 =
         new DownloadRequest(
             "key234",
-            TYPE_DASH,
+            /* type= */ "test",
             Uri.parse("https://www.test.com/download2"),
             asList(expectedStreamKey2),
             /* customCacheKey= */ "key234",
@@ -100,7 +100,7 @@ public class ActionFileUpgradeUtilTest {
     DownloadRequest request =
         new DownloadRequest(
             "id",
-            TYPE_DASH,
+            TYPE_PROGRESSIVE,
             Uri.parse("https://www.test.com/download"),
             asList(
                 new StreamKey(/* periodIndex= */ 0, /* groupIndex= */ 1, /* trackIndex= */ 2),
@@ -122,7 +122,7 @@ public class ActionFileUpgradeUtilTest {
     DownloadRequest request1 =
         new DownloadRequest(
             "id",
-            TYPE_DASH,
+            TYPE_PROGRESSIVE,
             Uri.parse("https://www.test.com/download1"),
             asList(streamKey1),
             /* customCacheKey= */ "key123",
@@ -130,7 +130,7 @@ public class ActionFileUpgradeUtilTest {
     DownloadRequest request2 =
         new DownloadRequest(
             "id",
-            TYPE_DASH,
+            TYPE_PROGRESSIVE,
             Uri.parse("https://www.test.com/download2"),
             asList(streamKey2),
             /* customCacheKey= */ "key123",
diff --git a/library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadRequestTest.java b/library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadRequestTest.java
index d298dd58b8..a55b1e1283 100644
--- a/library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadRequestTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadRequestTest.java
@@ -17,6 +17,7 @@ package com.google.android.exoplayer2.offline;
 
 import static com.google.android.exoplayer2.offline.DownloadRequest.TYPE_DASH;
 import static com.google.android.exoplayer2.offline.DownloadRequest.TYPE_HLS;
+import static com.google.android.exoplayer2.offline.DownloadRequest.TYPE_PROGRESSIVE;
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.fail;
 
@@ -139,7 +140,7 @@ public class DownloadRequestTest {
     DownloadRequest request1 =
         new DownloadRequest(
             "id1",
-            TYPE_DASH,
+            TYPE_PROGRESSIVE,
             uri1,
             /* streamKeys= */ Collections.emptyList(),
             "key1",
@@ -147,7 +148,7 @@ public class DownloadRequestTest {
     DownloadRequest request2 =
         new DownloadRequest(
             "id1",
-            TYPE_DASH,
+            TYPE_PROGRESSIVE,
             uri2,
             /* streamKeys= */ Collections.emptyList(),
             "key2",