From 3ec9c99644e12640884f39c08f549d3f43fead41 Mon Sep 17 00:00:00 2001
From: kimvde <kimvde@google.com>
Date: Wed, 25 Sep 2024 08:01:39 -0700
Subject: [PATCH] Document that the MediaItem's image duration should be set
 for images

PiperOrigin-RevId: 678702334
---
 RELEASENOTES.md                                    |  2 ++
 .../transformer/DefaultAssetLoaderFactory.java     |  9 +++++++++
 .../media3/transformer/EditedMediaItem.java        | 14 ++++++++++----
 3 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index 30d3ac48cf..ba5882631a 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -49,6 +49,8 @@
         allow invoking events of subclass listeners
         ([1736](https://github.com/androidx/media/pull/1736)).
 *   Transformer:
+    *   Make setting the image duration using
+        `MediaItem.Builder.setImageDurationMs` mandatory for image export.
     *   Add export support for gaps in sequences of audio EditedMediaItems.
 *   Track Selection:
 *   Extractors:
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 b3394c1ecc..92366de0f3 100644
--- a/libraries/transformer/src/main/java/androidx/media3/transformer/DefaultAssetLoaderFactory.java
+++ b/libraries/transformer/src/main/java/androidx/media3/transformer/DefaultAssetLoaderFactory.java
@@ -16,15 +16,19 @@
 
 package androidx.media3.transformer;
 
+import static androidx.media3.common.util.Assertions.checkNotNull;
+
 import android.content.Context;
 import android.graphics.BitmapFactory;
 import android.graphics.ColorSpace;
 import android.os.Looper;
 import androidx.annotation.Nullable;
+import androidx.media3.common.C;
 import androidx.media3.common.MediaItem;
 import androidx.media3.common.MimeTypes;
 import androidx.media3.common.util.BitmapLoader;
 import androidx.media3.common.util.Clock;
+import androidx.media3.common.util.Log;
 import androidx.media3.common.util.UnstableApi;
 import androidx.media3.common.util.Util;
 import androidx.media3.datasource.DataSourceBitmapLoader;
@@ -39,6 +43,8 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 @UnstableApi
 public final class DefaultAssetLoaderFactory implements AssetLoader.Factory {
 
+  private static final String TAG = "DefaultAssetLoaderFact";
+
   // Limit decoded images to 4096x4096 - should be large enough for most image to video
   // transcode operations, and smaller than GL_MAX_TEXTURE_SIZE for most devices.
   // TODO: b/356072337 - consider reading this from GL_MAX_TEXTURE_SIZE. This requires an
@@ -136,6 +142,9 @@ public final class DefaultAssetLoaderFactory implements AssetLoader.Factory {
       CompositionSettings compositionSettings) {
     MediaItem mediaItem = editedMediaItem.mediaItem;
     if (isImage(mediaItem)) {
+      if (checkNotNull(mediaItem.localConfiguration).imageDurationMs == C.TIME_UNSET) {
+        Log.w(TAG, "The imageDurationMs field must be set on image MediaItems.");
+      }
       if (imageAssetLoaderFactory == null) {
         imageAssetLoaderFactory = new ImageAssetLoader.Factory(context, bitmapLoader);
       }
diff --git a/libraries/transformer/src/main/java/androidx/media3/transformer/EditedMediaItem.java b/libraries/transformer/src/main/java/androidx/media3/transformer/EditedMediaItem.java
index dbd584af46..16d06a8335 100644
--- a/libraries/transformer/src/main/java/androidx/media3/transformer/EditedMediaItem.java
+++ b/libraries/transformer/src/main/java/androidx/media3/transformer/EditedMediaItem.java
@@ -50,10 +50,16 @@ public final class EditedMediaItem {
     /**
      * Creates an instance.
      *
-     * <p>For image inputs, the values passed into {@link #setRemoveAudio}, {@link #setRemoveVideo}
-     * and {@link #setFlattenForSlowMotion} will be ignored. For multi-picture formats (e.g. gifs),
-     * a single image frame from the container is displayed if the {@link DefaultAssetLoaderFactory}
-     * is used.
+     * <p>For image inputs:
+     *
+     * <ul>
+     *   <li>The {@linkplain MediaItem.Builder#setImageDurationMs(long) image duration} should
+     *       always be set.
+     *   <li>The values passed into {@link #setRemoveAudio}, {@link #setRemoveVideo} and {@link
+     *       #setFlattenForSlowMotion} will be ignored.
+     *   <li>For multi-picture formats (e.g. gifs), a single image frame from the container is
+     *       displayed if the {@link DefaultAssetLoaderFactory} is used.
+     * </ul>
      *
      * @param mediaItem The {@link MediaItem} on which transformations are applied.
      */