diff --git a/libraries/common/src/main/java/androidx/media3/common/FileTypes.java b/libraries/common/src/main/java/androidx/media3/common/FileTypes.java
index d4dff3266b..c31de70e68 100644
--- a/libraries/common/src/main/java/androidx/media3/common/FileTypes.java
+++ b/libraries/common/src/main/java/androidx/media3/common/FileTypes.java
@@ -19,7 +19,6 @@ import static androidx.media3.common.MimeTypes.normalizeMimeType;
 import static java.lang.annotation.ElementType.TYPE_USE;
 
 import android.net.Uri;
-import android.text.TextUtils;
 import androidx.annotation.IntDef;
 import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
@@ -30,7 +29,6 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 import java.util.List;
 import java.util.Map;
-import java.util.regex.Pattern;
 
 /** Defines common file type constants and helper methods. */
 @UnstableApi
@@ -329,30 +327,4 @@ public final class FileTypes {
       return FileTypes.UNKNOWN;
     }
   }
-
-  /**
-   * Returns the file extension of the given {@link Uri} or an empty string if there is no
-   * extension.
-   *
-   * <p>This method is a convenience method for obtaining the extension of a url and has undefined
-   * results for other Strings.
-   */
-  public static String getFileExtensionFromUri(Uri uri) {
-    String path = uri.getPath();
-    if (TextUtils.isEmpty(path)) {
-      return "";
-    }
-    int filenamePos = path.lastIndexOf('/');
-    String filename = 0 <= filenamePos ? path.substring(filenamePos + 1) : path;
-
-    // If the filename contains special characters, we don't consider it valid for our matching
-    // purposes.
-    if (!filename.isEmpty() && Pattern.matches("[a-zA-Z_0-9\\.\\-\\(\\)\\%]+", filename)) {
-      int dotPos = filename.lastIndexOf('.');
-      if (0 <= dotPos) {
-        return filename.substring(dotPos + 1);
-      }
-    }
-    return "";
-  }
 }
diff --git a/libraries/transformer/src/main/java/androidx/media3/transformer/DefaultAssetLoaderFactory.java b/libraries/transformer/src/main/java/androidx/media3/transformer/DefaultAssetLoaderFactory.java
index a21c9ac7ae..edc458836e 100644
--- a/libraries/transformer/src/main/java/androidx/media3/transformer/DefaultAssetLoaderFactory.java
+++ b/libraries/transformer/src/main/java/androidx/media3/transformer/DefaultAssetLoaderFactory.java
@@ -16,6 +16,7 @@
 
 package androidx.media3.transformer;
 
+import static androidx.media3.common.util.Assertions.checkNotNull;
 import static androidx.media3.common.util.Assertions.checkState;
 
 import android.content.ContentResolver;
@@ -24,7 +25,6 @@ import android.graphics.BitmapFactory;
 import android.graphics.ColorSpace;
 import android.os.Looper;
 import androidx.annotation.Nullable;
-import androidx.media3.common.FileTypes;
 import androidx.media3.common.MediaItem;
 import androidx.media3.common.MimeTypes;
 import androidx.media3.common.util.BitmapLoader;
@@ -175,8 +175,12 @@ public final class DefaultAssetLoaderFactory implements AssetLoader.Factory {
         ContentResolver cr = context.getContentResolver();
         mimeType = cr.getType(localConfiguration.uri);
       } else {
-        String fileExtension = FileTypes.getFileExtensionFromUri(localConfiguration.uri);
-        mimeType = getCommonImageMimeTypeFromExtension(Ascii.toLowerCase(fileExtension));
+        String uriPath = checkNotNull(localConfiguration.uri.getPath());
+        int fileExtensionStart = uriPath.lastIndexOf(".");
+        if (fileExtensionStart != -1) {
+          String extension = Ascii.toLowerCase(uriPath.substring(fileExtensionStart + 1));
+          mimeType = getCommonImageMimeTypeFromExtension(Ascii.toLowerCase(extension));
+        }
       }
     }
     if (mimeType == null) {