diff --git a/library/core/src/main/java/com/google/android/exoplayer2/mediacodec/AsynchronousMediaCodecCallback.java b/library/core/src/main/java/com/google/android/exoplayer2/mediacodec/AsynchronousMediaCodecCallback.java
index 1302549ac8..872cc77d6a 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/mediacodec/AsynchronousMediaCodecCallback.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/mediacodec/AsynchronousMediaCodecCallback.java
@@ -17,6 +17,7 @@
 package com.google.android.exoplayer2.mediacodec;
 
 import static com.google.android.exoplayer2.util.Assertions.checkState;
+import static com.google.android.exoplayer2.util.Assertions.checkStateNotNull;
 
 import android.media.MediaCodec;
 import android.media.MediaFormat;
@@ -155,6 +156,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
         } else {
           int bufferIndex = availableOutputBuffers.remove();
           if (bufferIndex >= 0) {
+            checkStateNotNull(currentFormat);
             MediaCodec.BufferInfo nextBufferInfo = bufferInfos.remove();
             bufferInfo.set(
                 nextBufferInfo.offset,
diff --git a/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/AsynchronousMediaCodecCallbackTest.java b/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/AsynchronousMediaCodecCallbackTest.java
index 3765da56b1..fbb031a64b 100644
--- a/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/AsynchronousMediaCodecCallbackTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/AsynchronousMediaCodecCallbackTest.java
@@ -175,7 +175,8 @@ public class AsynchronousMediaCodecCallbackTest {
 
   @Test
   public void dequeOutputBufferIndex_returnsEnqueuedBuffers() {
-    // Send two output buffers to the callback.
+    // Send an output format and two output buffers to the callback.
+    asynchronousMediaCodecCallback.onOutputFormatChanged(codec, createMediaFormat("format0"));
     MediaCodec.BufferInfo bufferInfo1 = new MediaCodec.BufferInfo();
     asynchronousMediaCodecCallback.onOutputBufferAvailable(codec, 0, bufferInfo1);
     MediaCodec.BufferInfo bufferInfo2 = new MediaCodec.BufferInfo();
@@ -183,6 +184,10 @@ public class AsynchronousMediaCodecCallbackTest {
     asynchronousMediaCodecCallback.onOutputBufferAvailable(codec, 1, bufferInfo2);
 
     MediaCodec.BufferInfo outBufferInfo = new MediaCodec.BufferInfo();
+    assertThat(asynchronousMediaCodecCallback.dequeueOutputBufferIndex(outBufferInfo))
+        .isEqualTo(MediaCodec.INFO_OUTPUT_FORMAT_CHANGED);
+    assertThat(asynchronousMediaCodecCallback.getOutputFormat().getString("name"))
+        .isEqualTo("format0");
     assertThat(asynchronousMediaCodecCallback.dequeueOutputBufferIndex(outBufferInfo)).isEqualTo(0);
     assertBufferInfosEqual(bufferInfo1, outBufferInfo);
     assertThat(asynchronousMediaCodecCallback.dequeueOutputBufferIndex(outBufferInfo)).isEqualTo(1);
@@ -235,8 +240,9 @@ public class AsynchronousMediaCodecCallbackTest {
     Looper callbackThreadLooper = callbackThread.getLooper();
     AtomicBoolean flushCompleted = new AtomicBoolean();
 
-    // Send two output buffers to the callback, then flush(), then send
+    // Send an output format and two output buffers to the callback, then flush(), then send
     // another output buffer.
+    asynchronousMediaCodecCallback.onOutputFormatChanged(codec, createMediaFormat("format0"));
     asynchronousMediaCodecCallback.onOutputBufferAvailable(codec, 0, bufferInfo);
     asynchronousMediaCodecCallback.onOutputBufferAvailable(codec, 1, bufferInfo);
     asynchronousMediaCodecCallback.flushAsync(
@@ -247,6 +253,10 @@ public class AsynchronousMediaCodecCallbackTest {
     MediaCodec.BufferInfo outBufferInfo = new MediaCodec.BufferInfo();
 
     assertThat(flushCompleted.get()).isTrue();
+    assertThat(asynchronousMediaCodecCallback.dequeueOutputBufferIndex(outBufferInfo))
+        .isEqualTo(MediaCodec.INFO_OUTPUT_FORMAT_CHANGED);
+    assertThat(asynchronousMediaCodecCallback.getOutputFormat().getString("name"))
+        .isEqualTo("format0");
     assertThat(asynchronousMediaCodecCallback.dequeueOutputBufferIndex(outBufferInfo)).isEqualTo(2);
   }