diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index 582527a796..c81a93d3f2 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -66,6 +66,9 @@
         `Surface` in `configure` and calls to a new method `detachOutputSurface`
         to remove a previously set `Surface` if the codec supports this
         (`MediaCodecInfo.detachedSurfaceSupported`).
+    *   Use `MediaCodecAdapter` supplied pixel aspect ratio values if provided
+        when processing `onOutputFormatChanged`
+        ([#1371](https://github.com/androidx/media/pull/1371)).
 *   Text:
 *   Metadata:
 *   Image:
diff --git a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/video/MediaCodecVideoRenderer.java b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/video/MediaCodecVideoRenderer.java
index bf74a4b8ed..a7c31e671e 100644
--- a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/video/MediaCodecVideoRenderer.java
+++ b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/video/MediaCodecVideoRenderer.java
@@ -1342,16 +1342,17 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer
               ? mediaFormat.getInteger(KEY_CROP_BOTTOM) - mediaFormat.getInteger(KEY_CROP_TOP) + 1
               : mediaFormat.getInteger(MediaFormat.KEY_HEIGHT);
     }
-    boolean hasPixelAspectRatio =
-        (Util.SDK_INT >= 30)
-            && mediaFormat != null
-            && mediaFormat.containsKey(MediaFormat.KEY_PIXEL_ASPECT_RATIO_WIDTH)
-            && mediaFormat.containsKey(MediaFormat.KEY_PIXEL_ASPECT_RATIO_HEIGHT);
-    pixelWidthHeightRatio =
-        hasPixelAspectRatio
-            ? (float) mediaFormat.getInteger(MediaFormat.KEY_PIXEL_ASPECT_RATIO_WIDTH)
-                / mediaFormat.getInteger(MediaFormat.KEY_PIXEL_ASPECT_RATIO_HEIGHT)
-            : format.pixelWidthHeightRatio;
+
+    pixelWidthHeightRatio = format.pixelWidthHeightRatio;
+    if (Util.SDK_INT >= 30
+        && mediaFormat != null
+        && mediaFormat.containsKey(MediaFormat.KEY_PIXEL_ASPECT_RATIO_WIDTH)
+        && mediaFormat.containsKey(MediaFormat.KEY_PIXEL_ASPECT_RATIO_HEIGHT)) {
+      pixelWidthHeightRatio =
+          (float) mediaFormat.getInteger(MediaFormat.KEY_PIXEL_ASPECT_RATIO_WIDTH)
+              / mediaFormat.getInteger(MediaFormat.KEY_PIXEL_ASPECT_RATIO_HEIGHT);
+    }
+
     // The decoder applies the rotation when rendering to the surface. For 90 and 270 degree
     // rotations, we need to flip the width, height and pixel aspect ratio to reflect the rotation
     // that was applied.
diff --git a/libraries/exoplayer/src/test/java/androidx/media3/exoplayer/video/MediaCodecVideoRendererTest.java b/libraries/exoplayer/src/test/java/androidx/media3/exoplayer/video/MediaCodecVideoRendererTest.java
index fa084d8e10..1954a14697 100644
--- a/libraries/exoplayer/src/test/java/androidx/media3/exoplayer/video/MediaCodecVideoRendererTest.java
+++ b/libraries/exoplayer/src/test/java/androidx/media3/exoplayer/video/MediaCodecVideoRendererTest.java
@@ -116,6 +116,7 @@ public class MediaCodecVideoRendererTest {
           .setSampleMimeType(MimeTypes.VIDEO_H264)
           .setWidth(1920)
           .setHeight(1080)
+          .setPixelWidthHeightRatio(1.0f)
           .build();
 
   private static final TrackGroup TRACK_GROUP_H264 = new TrackGroup(VIDEO_H264);
@@ -762,12 +763,9 @@ public class MediaCodecVideoRendererTest {
               public MediaFormat getOutputFormat() {
                 MediaFormat mediaFormat = adapter.getOutputFormat();
                 if (Util.SDK_INT >= 30) {
-                  int pixelAspectRatioHeight = 1 << 30; // Max integer power of 2.
-                  int pixelAspectRatioWidth = (int) (0.5f * pixelAspectRatioHeight);
-                  mediaFormat.setInteger(
-                      MediaFormat.KEY_PIXEL_ASPECT_RATIO_WIDTH, pixelAspectRatioWidth);
-                  mediaFormat.setInteger(
-                      MediaFormat.KEY_PIXEL_ASPECT_RATIO_HEIGHT, pixelAspectRatioHeight);
+                  // Change to 9:16 Ratio
+                  mediaFormat.setInteger(MediaFormat.KEY_PIXEL_ASPECT_RATIO_WIDTH, 9);
+                  mediaFormat.setInteger(MediaFormat.KEY_PIXEL_ASPECT_RATIO_HEIGHT, 16);
                 }
                 return mediaFormat;
               }
@@ -825,7 +823,9 @@ public class MediaCodecVideoRendererTest {
     verify(eventListener)
         .onVideoSizeChanged(
             new VideoSize(
-                VIDEO_H264.width, VIDEO_H264.height, VIDEO_H264.pixelWidthHeightRatio / 2));
+                VIDEO_H264.width,
+                VIDEO_H264.height,
+                /* pixelWidthHeightRatio= */ VIDEO_H264.pixelWidthHeightRatio * (9.0f / 16.0f)));
   }
 
   @Test