diff --git a/library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/mh/SetHdrEditingTransformationTest.java b/library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/mh/SetHdrEditingTransformationTest.java
index ca030cbced..0a76c4c9e5 100644
--- a/library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/mh/SetHdrEditingTransformationTest.java
+++ b/library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/mh/SetHdrEditingTransformationTest.java
@@ -174,7 +174,7 @@ public class SetHdrEditingTransformationTest {
         assertThat(exception)
             .hasCauseThat()
             .hasMessageThat()
-            .isEqualTo("Tone-mapping requested but not supported by the decoder");
+            .isEqualTo("Tone-mapping requested but not supported by the decoder.");
       }
       return;
     }
diff --git a/library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/mh/SetHdrToSdrToneMapTransformationTest.java b/library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/mh/SetHdrToSdrToneMapTransformationTest.java
index 36ca215fce..09817cf1e1 100644
--- a/library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/mh/SetHdrToSdrToneMapTransformationTest.java
+++ b/library/transformer/src/androidTest/java/com/google/android/exoplayer2/transformer/mh/SetHdrToSdrToneMapTransformationTest.java
@@ -90,7 +90,7 @@ public class SetHdrToSdrToneMapTransformationTest {
         assertThat(exception)
             .hasCauseThat()
             .hasMessageThat()
-            .isEqualTo("Tone-mapping requested but not supported by the decoder");
+            .isEqualTo("Tone-mapping requested but not supported by the decoder.");
       }
       return;
     }
@@ -147,7 +147,7 @@ public class SetHdrToSdrToneMapTransformationTest {
         assertThat(exception)
             .hasCauseThat()
             .hasMessageThat()
-            .isEqualTo("Tone-mapping requested but not supported by the decoder");
+            .isEqualTo("Tone-mapping requested but not supported by the decoder.");
       }
       return;
     }
diff --git a/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/DefaultCodec.java b/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/DefaultCodec.java
index ba3647d706..0d82180abd 100644
--- a/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/DefaultCodec.java
+++ b/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/DefaultCodec.java
@@ -114,7 +114,7 @@ public final class DefaultCodec implements Codec {
         // https://developer.android.com/reference/android/media/MediaFormat#KEY_COLOR_TRANSFER_REQUEST.
         checkArgument(
             Api29.isSdrToneMappingEnabled(mediaCodec.getInputFormat()),
-            "Tone-mapping requested but not supported by the decoder");
+            "Tone-mapping requested but not supported by the decoder.");
       }
       if (isVideo && !isDecoder) {
         inputSurface = mediaCodec.createInputSurface();