Only set image duration on images in demo app

The Javadoc is stating that the image duration is ignored for non-image
input but this is incorrect (for example, it affects seeking
performance). The Javadoc will be updated in another CL.

PiperOrigin-RevId: 631730980

libraries/transformer/src/main/java/androidx/media3/transformer/DefaultAssetLoaderFactory.java

@@ -16,8 +16,8 @@
 
 package androidx.media3.transformer;
 
-import static androidx.media3.common.util.Assertions.checkNotNull;
 import static androidx.media3.common.util.Assertions.checkState;
+import static androidx.media3.transformer.ImageUtil.getCommonImageMimeTypeFromExtension;
 
 import android.content.ContentResolver;
 import android.content.Context;
@@ -35,7 +35,6 @@ import androidx.media3.datasource.DataSourceBitmapLoader;
 import androidx.media3.datasource.DefaultDataSource;
 import androidx.media3.exoplayer.source.MediaSource;
 import androidx.media3.transformer.AssetLoader.CompositionSettings;
-import com.google.common.base.Ascii;
 import com.google.common.util.concurrent.MoreExecutors;
 import java.util.Objects;
 import java.util.concurrent.Executors;
@@ -161,12 +160,7 @@ public final class DefaultAssetLoaderFactory implements AssetLoader.Factory {
         ContentResolver cr = context.getContentResolver();
         mimeType = cr.getType(localConfiguration.uri);
       } else {
-        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));
-        }
+        mimeType = getCommonImageMimeTypeFromExtension(localConfiguration.uri);
       }
     }
     if (mimeType == null) {
@@ -180,46 +174,4 @@ public final class DefaultAssetLoaderFactory implements AssetLoader.Factory {
         "Image format not supported by given bitmapLoader");
     return true;
   }
-
-  @Nullable
-  private static String getCommonImageMimeTypeFromExtension(String extension) {
-    switch (extension) {
-      case "bmp":
-      case "dib":
-        return MimeTypes.IMAGE_BMP;
-      case "heif":
-      case "heic":
-        return MimeTypes.IMAGE_HEIF;
-      case "jpg":
-      case "jpeg":
-      case "jpe":
-      case "jif":
-      case "jfif":
-      case "jfi":
-        return MimeTypes.IMAGE_JPEG;
-      case "png":
-        return MimeTypes.IMAGE_PNG;
-      case "webp":
-        return MimeTypes.IMAGE_WEBP;
-      case "gif":
-        return "image/gif";
-      case "tiff":
-      case "tif":
-        return "image/tiff";
-      case "raw":
-      case "arw":
-      case "cr2":
-      case "k25":
-        return "image/raw";
-      case "svg":
-      case "svgz":
-        return "image/svg+xml";
-      case "ico":
-        return "image/x-icon";
-      case "avif":
-        return "image/avif";
-      default:
-        return null;
-    }
-  }
 }

libraries/transformer/src/main/java/androidx/media3/transformer/ImageUtil.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package androidx.media3.transformer;
+
+import android.net.Uri;
+import androidx.annotation.Nullable;
+import androidx.media3.common.MimeTypes;
+import androidx.media3.common.util.UnstableApi;
+import com.google.common.base.Ascii;
+
+/** Utility methods for images. */
+@UnstableApi
+public final class ImageUtil {
+
+  private ImageUtil() {}
+
+  /**
+   * Returns the {@linkplain MimeTypes MIME type} corresponding to an image {@linkplain Uri URI}
+   * path extension. {@code null} is returned if the extension is not an image extension.
+   */
+  @Nullable
+  public static String getCommonImageMimeTypeFromExtension(Uri uri) {
+    @Nullable String path = uri.getPath();
+    if (path == null) {
+      return null;
+    }
+    int extensionIndex = path.lastIndexOf('.');
+    if (extensionIndex == -1 || extensionIndex == path.length() - 1) {
+      return null;
+    }
+    String extension = Ascii.toLowerCase(path.substring(extensionIndex + 1));
+    switch (extension) {
+      case "bmp":
+      case "dib":
+        return MimeTypes.IMAGE_BMP;
+      case "heif":
+      case "heic":
+        return MimeTypes.IMAGE_HEIF;
+      case "jpg":
+      case "jpeg":
+      case "jpe":
+      case "jif":
+      case "jfif":
+      case "jfi":
+        return MimeTypes.IMAGE_JPEG;
+      case "png":
+        return MimeTypes.IMAGE_PNG;
+      case "webp":
+        return MimeTypes.IMAGE_WEBP;
+      case "gif":
+        return "image/gif";
+      case "tiff":
+      case "tif":
+        return "image/tiff";
+      case "raw":
+      case "arw":
+      case "cr2":
+      case "k25":
+        return "image/raw";
+      case "svg":
+      case "svgz":
+        return "image/svg+xml";
+      case "ico":
+        return "image/x-icon";
+      case "avif":
+        return "image/avif";
+      default:
+        return null;
+    }
+  }
+}