Add AssetLoader.Factory

This is so that apps can customise AssetLoader

PiperOrigin-RevId: 494998497

library/transformer/src/main/java/com/google/android/exoplayer2/transformer/AssetLoader.java

@@ -16,7 +16,13 @@
 
 package com.google.android.exoplayer2.transformer;
 
+import android.content.Context;
+import android.os.Looper;
 import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.MediaItem;
+import com.google.android.exoplayer2.source.MediaSource;
+import com.google.android.exoplayer2.util.Clock;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 
 /**
  * Provides media data to a {@linkplain Transformer}.
@@ -28,6 +34,82 @@ import com.google.android.exoplayer2.Format;
  */
 public interface AssetLoader {
 
+  /** A factory for {@link AssetLoader} instances. */
+  interface Factory {
+
+    /** Sets the context. */
+    @CanIgnoreReturnValue
+    Factory setContext(Context context);
+
+    /** Sets the {@link MediaItem} to load. */
+    @CanIgnoreReturnValue
+    Factory setMediaItem(MediaItem mediaItem);
+
+    /**
+     * Sets whether to remove the audio samples from the output (if any).
+     *
+     * <p>The audio and video cannot both be removed because the output would not contain any
+     * samples.
+     */
+    @CanIgnoreReturnValue
+    Factory setRemoveAudio(boolean removeAudio);
+
+    /**
+     * Sets whether to remove the video samples from the output (if any).
+     *
+     * <p>The audio and video cannot both be removed because the output would not contain any
+     * samples.
+     */
+    @CanIgnoreReturnValue
+    Factory setRemoveVideo(boolean removeVideo);
+
+    /**
+     * Sets whether the video samples should be flattened prior to decoding for media containing
+     * slow motion markers.
+     *
+     * <p>The audio samples are flattened after they are output by the {@link AssetLoader}, because
+     * this is done on decoded samples.
+     *
+     * <p>For more information on slow motion flattening, see {@link
+     * TransformationRequest.Builder#setFlattenForSlowMotion(boolean)}.
+     */
+    @CanIgnoreReturnValue
+    Factory setFlattenVideoForSlowMotion(boolean flattenVideoForSlowMotion);
+
+    /** Sets the {@link MediaSource.Factory} to be used to retrieve the samples. */
+    @CanIgnoreReturnValue
+    Factory setMediaSourceFactory(MediaSource.Factory mediaSourceFactory);
+
+    /** Sets the {@link Codec.DecoderFactory} to be used to decode the samples (if necessary). */
+    @CanIgnoreReturnValue
+    Factory setDecoderFactory(Codec.DecoderFactory decoderFactory);
+
+    /**
+     * Sets the {@link Looper} that's used to access the {@link AssetLoader} after it's been
+     * created.
+     */
+    @CanIgnoreReturnValue
+    Factory setLooper(Looper looper);
+
+    /** Sets the {@link Listener} on which the {@link AssetLoader} should notify of events. */
+    @CanIgnoreReturnValue
+    Factory setListener(AssetLoader.Listener listener);
+
+    /**
+     * The {@link Clock} to use.
+     *
+     * <p>Should always be {@link Clock#DEFAULT} except for testing.
+     */
+    @CanIgnoreReturnValue
+    Factory setClock(Clock clock);
+
+    /**
+     * Creates an {@link AssetLoader} instance. All the setters in this factory must be called
+     * before creating the {@link AssetLoader}.
+     */
+    AssetLoader createAssetLoader();
+  }
+
   /**
    * A listener of asset loader events.
    *

library/transformer/src/main/java/com/google/android/exoplayer2/transformer/DefaultAssetLoaderFactory.java

@@ -0,0 +1,127 @@
+/*
+ * Copyright 2022 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 com.google.android.exoplayer2.transformer;
+
+import static com.google.android.exoplayer2.util.Assertions.checkStateNotNull;
+
+import android.content.Context;
+import android.os.Looper;
+import androidx.annotation.Nullable;
+import com.google.android.exoplayer2.MediaItem;
+import com.google.android.exoplayer2.source.MediaSource;
+import com.google.android.exoplayer2.util.Clock;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
+
+/** The default {@link AssetLoader.Factory} implementation. */
+public final class DefaultAssetLoaderFactory implements AssetLoader.Factory {
+
+  @Nullable private Context context;
+  @Nullable private MediaItem mediaItem;
+  private boolean removeAudio;
+  private boolean removeVideo;
+  private boolean flattenVideoForSlowMotion;
+  @Nullable private MediaSource.Factory mediaSourceFactory;
+  @Nullable private Codec.DecoderFactory decoderFactory;
+  @Nullable private Looper looper;
+  @Nullable private AssetLoader.Listener listener;
+  @Nullable private Clock clock;
+
+  @Override
+  @CanIgnoreReturnValue
+  public AssetLoader.Factory setContext(Context context) {
+    this.context = context;
+    return this;
+  }
+
+  @Override
+  @CanIgnoreReturnValue
+  public AssetLoader.Factory setMediaItem(MediaItem mediaItem) {
+    this.mediaItem = mediaItem;
+    return this;
+  }
+
+  @Override
+  @CanIgnoreReturnValue
+  public AssetLoader.Factory setRemoveAudio(boolean removeAudio) {
+    this.removeAudio = removeAudio;
+    return this;
+  }
+
+  @Override
+  @CanIgnoreReturnValue
+  public AssetLoader.Factory setRemoveVideo(boolean removeVideo) {
+    this.removeVideo = removeVideo;
+    return this;
+  }
+
+  @Override
+  @CanIgnoreReturnValue
+  public AssetLoader.Factory setFlattenVideoForSlowMotion(boolean flattenVideoForSlowMotion) {
+    this.flattenVideoForSlowMotion = flattenVideoForSlowMotion;
+    return this;
+  }
+
+  @Override
+  @CanIgnoreReturnValue
+  public AssetLoader.Factory setMediaSourceFactory(MediaSource.Factory mediaSourceFactory) {
+    this.mediaSourceFactory = mediaSourceFactory;
+    return this;
+  }
+
+  @Override
+  @CanIgnoreReturnValue
+  public AssetLoader.Factory setDecoderFactory(Codec.DecoderFactory decoderFactory) {
+    this.decoderFactory = decoderFactory;
+    return this;
+  }
+
+  @Override
+  @CanIgnoreReturnValue
+  public AssetLoader.Factory setLooper(Looper looper) {
+    this.looper = looper;
+    return this;
+  }
+
+  @Override
+  @CanIgnoreReturnValue
+  public AssetLoader.Factory setListener(AssetLoader.Listener listener) {
+    this.listener = listener;
+    return this;
+  }
+
+  @Override
+  @CanIgnoreReturnValue
+  public AssetLoader.Factory setClock(Clock clock) {
+    this.clock = clock;
+    return this;
+  }
+
+  @Override
+  public AssetLoader createAssetLoader() {
+    return new ExoPlayerAssetLoader(
+        checkStateNotNull(context),
+        checkStateNotNull(mediaItem),
+        removeAudio,
+        removeVideo,
+        flattenVideoForSlowMotion,
+        checkStateNotNull(mediaSourceFactory),
+        checkStateNotNull(decoderFactory),
+        checkStateNotNull(looper),
+        checkStateNotNull(listener),
+        checkStateNotNull(clock));
+  }
+}

library/transformer/src/main/java/com/google/android/exoplayer2/transformer/Transformer.java

@@ -90,6 +90,7 @@ public final class Transformer {
     private boolean forceSilentAudio;
     private ListenerSet<Transformer.Listener> listeners;
     private MediaSource.@MonotonicNonNull Factory mediaSourceFactory;
+    private AssetLoader.Factory assetLoaderFactory;
     private Codec.DecoderFactory decoderFactory;
     private Codec.EncoderFactory encoderFactory;
     private FrameProcessor.Factory frameProcessorFactory;
@@ -108,6 +109,7 @@ public final class Transformer {
       transformationRequest = new TransformationRequest.Builder().build();
       audioProcessors = ImmutableList.of();
       videoEffects = ImmutableList.of();
+      assetLoaderFactory = new DefaultAssetLoaderFactory();
       decoderFactory = new DefaultDecoderFactory(this.context);
       encoderFactory = new DefaultEncoderFactory.Builder(this.context).build();
       frameProcessorFactory = new GlEffectsFrameProcessor.Factory();
@@ -129,6 +131,7 @@ public final class Transformer {
       this.forceSilentAudio = transformer.forceSilentAudio;
       this.listeners = transformer.listeners;
       this.mediaSourceFactory = transformer.mediaSourceFactory;
+      this.assetLoaderFactory = transformer.assetLoaderFactory;
       this.decoderFactory = transformer.decoderFactory;
       this.encoderFactory = transformer.encoderFactory;
       this.frameProcessorFactory = transformer.frameProcessorFactory;
@@ -304,6 +307,20 @@ public final class Transformer {
       return this;
     }
 
+    /**
+     * Sets the {@link AssetLoader.Factory} to be used to retrieve the samples to transform.
+     *
+     * <p>The default value is a {@link DefaultAssetLoaderFactory}.
+     *
+     * @param assetLoaderFactory An {@link AssetLoader.Factory}.
+     * @return This builder.
+     */
+    @CanIgnoreReturnValue
+    public Builder setAssetLoaderFactory(AssetLoader.Factory assetLoaderFactory) {
+      this.assetLoaderFactory = assetLoaderFactory;
+      return this;
+    }
+
     /**
      * Sets the {@link Codec.DecoderFactory} that will be used by the transformer.
      *
@@ -476,6 +493,7 @@ public final class Transformer {
           forceSilentAudio,
           listeners,
           mediaSourceFactory,
+          assetLoaderFactory,
           decoderFactory,
           encoderFactory,
           frameProcessorFactory,
@@ -589,6 +607,7 @@ public final class Transformer {
   private final boolean forceSilentAudio;
   private final ListenerSet<Transformer.Listener> listeners;
   private final MediaSource.Factory mediaSourceFactory;
+  private final AssetLoader.Factory assetLoaderFactory;
   private final FrameProcessor.Factory frameProcessorFactory;
   private final Muxer.Factory muxerFactory;
   private final Looper looper;
@@ -607,6 +626,7 @@ public final class Transformer {
       boolean forceSilentAudio,
       ListenerSet<Listener> listeners,
       MediaSource.Factory mediaSourceFactory,
+      AssetLoader.Factory assetLoaderFactory,
       Codec.DecoderFactory decoderFactory,
       Codec.EncoderFactory encoderFactory,
       FrameProcessor.Factory frameProcessorFactory,
@@ -628,6 +648,7 @@ public final class Transformer {
     this.forceSilentAudio = forceSilentAudio;
     this.listeners = listeners;
     this.mediaSourceFactory = mediaSourceFactory;
+    this.assetLoaderFactory = assetLoaderFactory;
     this.decoderFactory = decoderFactory;
     this.encoderFactory = encoderFactory;
     this.frameProcessorFactory = frameProcessorFactory;
@@ -770,6 +791,7 @@ public final class Transformer {
             removeVideo,
             forceSilentAudio,
             mediaSourceFactory,
+            assetLoaderFactory,
             decoderFactory,
             encoderFactory,
             frameProcessorFactory,

library/transformer/src/main/java/com/google/android/exoplayer2/transformer/TransformerInternal.java

@@ -128,6 +128,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       boolean removeVideo,
       boolean forceSilentAudio,
       MediaSource.Factory mediaSourceFactory,
+      AssetLoader.Factory assetLoaderFactory,
       Codec.DecoderFactory decoderFactory,
       Codec.EncoderFactory encoderFactory,
       FrameProcessor.Factory frameProcessorFactory,
@@ -152,17 +153,18 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     Looper internalLooper = internalHandlerThread.getLooper();
     ComponentListener componentListener = new ComponentListener(mediaItem, fallbackListener);
     assetLoader =
-        new ExoPlayerAssetLoader(
-            context,
-            mediaItem,
-            removeAudio,
-            removeVideo,
-            transformationRequest.flattenForSlowMotion,
-            mediaSourceFactory,
-            decoderFactory,
-            internalLooper,
-            componentListener,
-            clock);
+        assetLoaderFactory
+            .setContext(context)
+            .setMediaItem(mediaItem)
+            .setRemoveAudio(removeAudio)
+            .setRemoveVideo(removeVideo)
+            .setFlattenVideoForSlowMotion(transformationRequest.flattenForSlowMotion)
+            .setMediaSourceFactory(mediaSourceFactory)
+            .setDecoderFactory(decoderFactory)
+            .setLooper(internalLooper)
+            .setListener(componentListener)
+            .setClock(clock)
+            .createAssetLoader();
     samplePipelines = new ArrayList<>();
     silentSamplePipelineIndex = C.INDEX_UNSET;
     dequeueBufferConditionVariable = new ConditionVariable();