Fix review comment

Author: claincly

libraries/common/src/main/java/androidx/media3/common/VideoGraph.java

@@ -16,6 +16,7 @@
 
 package androidx.media3.common;
 
+import androidx.annotation.IntRange;
 import androidx.annotation.Nullable;
 import androidx.media3.common.util.UnstableApi;
 
@@ -73,20 +74,23 @@ interface Listener {
    * A underlying processing {@link VideoFrameProcessor} is created every time this method is
    * called.
    *
+   * All inputs must be registered before rendering frames to the underlying
+   * {@link #getProcessor(int) VideoFrameProcessor}.
+   *
    * If the method throws, the caller must call {@link #release}.
    *
-   * @param sequenceIndex The sequence index of the input which can aid ordering of the inputs. The
-   *     index must start from 0.
+   * @param inputIndex The index of the input which could be used to order the inputs.
+   *     The index must start from 0.
    */
-  void registerInput(int sequenceIndex) throws VideoFrameProcessingException;
+  void registerInput(@IntRange(from = 0) int inputIndex) throws VideoFrameProcessingException;
 
   /**
    * Returns the {@link VideoFrameProcessor} that handles the processing for an input registered via
-   * {@link #registerInput(int)}. If the {@code sequenceIndex} is not {@linkplain
+   * {@link #registerInput(int)}. If the {@code inputIndex} is not {@linkplain
    * #registerInput(int) registered} before, this method will throw an {@link
    * IllegalStateException}.
    */
-  VideoFrameProcessor getProcessor(int sequenceIndex);
+  VideoFrameProcessor getProcessor(int inputIndex);
 
   /**
    * Sets the output surface and supporting information.

libraries/effect/src/main/java/androidx/media3/effect/DefaultVideoCompositor.java

@@ -18,6 +18,7 @@
 import static androidx.media3.common.util.Assertions.checkNotNull;
 import static androidx.media3.common.util.Assertions.checkState;
 import static androidx.media3.common.util.Assertions.checkStateNotNull;
+import static androidx.media3.common.util.Util.contains;
 import static java.lang.Math.abs;
 import static java.lang.Math.max;
 
@@ -78,7 +79,8 @@ public final class DefaultVideoCompositor implements VideoCompositor {
 
   private static final String THREAD_NAME = "Effect:DefaultVideoCompositor:GlThread";
   private static final String TAG = "DefaultVideoCompositor";
-  private static final int PRIMARY_INPUT_ID = 0;
+  // TODO: b/338579287: Use the first registered index instead of a constant value.
+  private static final int PRIMARY_INPUT_INDEX = 0;
 
   private final VideoCompositor.Listener listener;
   private final GlTextureProducer.Listener textureOutputListener;
@@ -142,32 +144,35 @@ public DefaultVideoCompositor(
   }
 
   @Override
-  public synchronized void registerInputSource(int sequenceIndex) {
-    inputSources.put(sequenceIndex, new InputSource());
+  public synchronized void registerInputSource(@IntRange(from = 0) int inputIndex) {
+    checkState(!contains(inputSources, inputIndex));
+    inputSources.put(inputIndex, new InputSource());
   }
 
   @Override
-  public synchronized void signalEndOfInputSource(int inputId) {
-    inputSources.get(inputId).isInputEnded = true;
+  public synchronized void signalEndOfInputSource(int inputIndex) {
+    checkState(contains(inputSources, inputIndex));
+    inputSources.get(inputIndex).isInputEnded = true;
     boolean allInputsEnded = true;
     for (int i = 0; i < inputSources.size(); i++) {
-      if (!inputSources.get(inputSources.keyAt(i)).isInputEnded) {
+      if (!inputSources.valueAt(i).isInputEnded) {
         allInputsEnded = false;
         break;
       }
     }
 
     this.allInputsEnded = allInputsEnded;
-    if (inputSources.get(PRIMARY_INPUT_ID).frameInfos.isEmpty()) {
-      if (inputId == PRIMARY_INPUT_ID) {
+    if (inputSources.get(PRIMARY_INPUT_INDEX).frameInfos.isEmpty()) {
+      if (inputIndex == PRIMARY_INPUT_INDEX) {
         releaseExcessFramesInAllSecondaryStreams();
       }
       if (allInputsEnded) {
         listener.onEnded();
         return;
       }
     }
-    if (inputId != PRIMARY_INPUT_ID && inputSources.get(inputId).frameInfos.size() == 1) {
+    if (inputIndex != PRIMARY_INPUT_INDEX
+        && inputSources.get(inputIndex).frameInfos.size() == 1) {
       // When a secondary stream ends input, composite if there was only one pending frame in the
       // stream.
       videoFrameProcessingTaskExecutor.submit(this::maybeComposite);
@@ -176,12 +181,13 @@ public synchronized void signalEndOfInputSource(int inputId) {
 
   @Override
   public synchronized void queueInputTexture(
-      int inputId,
+      int inputIndex,
       GlTextureProducer textureProducer,
       GlTextureInfo inputTexture,
       ColorInfo colorInfo,
       long presentationTimeUs) {
-    InputSource inputSource = inputSources.get(inputId);
+    checkState(contains(inputSources, inputIndex));
+    InputSource inputSource = inputSources.get(inputIndex);
     checkState(!inputSource.isInputEnded);
     checkStateNotNull(!ColorInfo.isTransferHdr(colorInfo), "HDR input is not supported.");
     if (configuredColorInfo == null) {
@@ -195,10 +201,10 @@ public synchronized void queueInputTexture(
             textureProducer,
             inputTexture,
             presentationTimeUs,
-            settings.getOverlaySettings(inputId, presentationTimeUs));
+            settings.getOverlaySettings(inputIndex, presentationTimeUs));
     inputSource.frameInfos.add(inputFrameInfo);
 
-    if (inputId == PRIMARY_INPUT_ID) {
+    if (inputIndex == PRIMARY_INPUT_INDEX) {
       releaseExcessFramesInAllSecondaryStreams();
     } else {
       releaseExcessFramesInSecondaryStream(inputSource);
@@ -224,11 +230,11 @@ public void releaseOutputTexture(long presentationTimeUs) {
   }
 
   private synchronized void releaseExcessFramesInAllSecondaryStreams() {
-    for (int i = 0; i < inputSources.size(); i++) {
-      if (i == PRIMARY_INPUT_ID) {
+    for (int inputIndex = 0; inputIndex < inputSources.size(); inputIndex++) {
+      if (inputIndex == PRIMARY_INPUT_INDEX) {
         continue;
       }
-      releaseExcessFramesInSecondaryStream(inputSources.get(inputSources.keyAt(i)));
+      releaseExcessFramesInSecondaryStream(inputSources.valueAt(inputIndex));
     }
   }
 
@@ -240,7 +246,7 @@ private synchronized void releaseExcessFramesInAllSecondaryStreams() {
    * began.
    */
   private synchronized void releaseExcessFramesInSecondaryStream(InputSource secondaryInputSource) {
-    InputSource primaryInputSource = inputSources.get(PRIMARY_INPUT_ID);
+    InputSource primaryInputSource = inputSources.get(PRIMARY_INPUT_INDEX);
     // If the primary stream output is ended, all secondary frames can be released.
     if (primaryInputSource.frameInfos.isEmpty() && primaryInputSource.isInputEnded) {
       releaseFrames(
@@ -291,7 +297,7 @@ private synchronized void maybeComposite()
       return;
     }
 
-    InputFrameInfo primaryInputFrame = framesToComposite.get(PRIMARY_INPUT_ID);
+    InputFrameInfo primaryInputFrame = framesToComposite.get(PRIMARY_INPUT_INDEX);
 
     ImmutableList.Builder<Size> inputSizes = new ImmutableList.Builder<>();
     for (int i = 0; i < framesToComposite.size(); i++) {
@@ -312,7 +318,7 @@ private synchronized void maybeComposite()
     textureOutputListener.onTextureRendered(
         /* textureProducer= */ this, outputTexture, outputPresentationTimestampUs, syncObject);
 
-    InputSource primaryInputSource = inputSources.get(PRIMARY_INPUT_ID);
+    InputSource primaryInputSource = inputSources.get(PRIMARY_INPUT_INDEX);
     releaseFrames(primaryInputSource, /* numberOfFramesToRelease= */ 1);
     releaseExcessFramesInAllSecondaryStreams();
 
@@ -332,18 +338,18 @@ private synchronized ImmutableList getFramesToComposite() {
     if (outputTexturePool.freeTextureCount() == 0) {
       return ImmutableList.of();
     }
-    for (int inputId = 0; inputId < inputSources.size(); inputId++) {
-      if (inputSources.get(inputSources.keyAt(inputId)).frameInfos.isEmpty()) {
+    for (int i = 0; i < inputSources.size(); i++) {
+      if (inputSources.valueAt(i).frameInfos.isEmpty()) {
         return ImmutableList.of();
       }
     }
     ImmutableList.Builder<InputFrameInfo> framesToComposite = new ImmutableList.Builder<>();
     InputFrameInfo primaryFrameToComposite =
-        inputSources.get(PRIMARY_INPUT_ID).frameInfos.element();
+        inputSources.get(PRIMARY_INPUT_INDEX).frameInfos.element();
     framesToComposite.add(primaryFrameToComposite);
 
-    for (int inputId = 0; inputId < inputSources.size(); inputId++) {
-      if (inputId == PRIMARY_INPUT_ID) {
+    for (int i = 0; i < inputSources.size(); i++) {
+      if (i == PRIMARY_INPUT_INDEX) {
         continue;
       }
       // Select the secondary streams' frame that would be composited next. The frame selected is
@@ -352,7 +358,7 @@ private synchronized ImmutableList getFramesToComposite() {
       //   2. Two or more frames, and at least one frame has timestamp greater than the target
       //      timestamp.
       // The smaller timestamp is taken if two timestamps have the same distance from the primary.
-      InputSource secondaryInputSource = inputSources.get(inputSources.keyAt(inputId));
+      InputSource secondaryInputSource = inputSources.valueAt(i);
       if (secondaryInputSource.frameInfos.size() == 1 && !secondaryInputSource.isInputEnded) {
         return ImmutableList.of();
       }

libraries/effect/src/main/java/androidx/media3/effect/MultipleInputVideoGraph.java

@@ -33,6 +33,7 @@
 import android.opengl.EGLDisplay;
 import android.opengl.EGLSurface;
 import android.util.SparseArray;
+import androidx.annotation.IntRange;
 import androidx.annotation.Nullable;
 import androidx.media3.common.C;
 import androidx.media3.common.ColorInfo;
@@ -211,9 +212,10 @@ public void onEnded() {
   }
 
   @Override
-  public void registerInput(int sequenceIndex) throws VideoFrameProcessingException {
-    checkStateNotNull(videoCompositor);
-    videoCompositor.registerInputSource(sequenceIndex);
+  public void registerInput(@IntRange(from = 0) int inputIndex)
+      throws VideoFrameProcessingException {
+    checkState(!contains(preProcessors, inputIndex));
+    checkNotNull(videoCompositor).registerInputSource(inputIndex);
     // Creating a new VideoFrameProcessor for the input.
     VideoFrameProcessor preProcessor =
         videoFrameProcessorFactory
@@ -222,7 +224,7 @@ public void registerInput(int sequenceIndex) throws VideoFrameProcessingExceptio
                 // Texture output to compositor.
                 (textureProducer, texture, presentationTimeUs, syncObject) ->
                     queuePreProcessingOutputToCompositor(
-                        sequenceIndex, textureProducer, texture, presentationTimeUs),
+                        inputIndex, textureProducer, texture, presentationTimeUs),
                 PRE_COMPOSITOR_TEXTURE_OUTPUT_CAPACITY)
             .build()
             .create(
@@ -253,16 +255,16 @@ public void onError(VideoFrameProcessingException exception) {
 
                   @Override
                   public void onEnded() {
-                    onPreProcessingVideoFrameProcessorEnded(sequenceIndex);
+                    onPreProcessingVideoFrameProcessorEnded(inputIndex);
                   }
                 });
-    preProcessors.put(sequenceIndex, preProcessor);
+    preProcessors.put(inputIndex, preProcessor);
   }
 
   @Override
-  public VideoFrameProcessor getProcessor(int sequenceIndex) {
-    checkState(contains(preProcessors, sequenceIndex));
-    return preProcessors.get(sequenceIndex);
+  public VideoFrameProcessor getProcessor(int inputIndex) {
+    checkState(contains(preProcessors, inputIndex));
+    return preProcessors.get(inputIndex);
   }
 
   @Override

libraries/effect/src/main/java/androidx/media3/effect/PreviewingSingleInputVideoGraph.java

@@ -109,6 +109,6 @@ private PreviewingSingleInputVideoGraph(
 
   @Override
   public void renderOutputFrame(long renderTimeNs) {
-    getProcessor(SINGLE_INPUT_INDEX).renderOutputFrame(renderTimeNs);
+    getProcessor(getInputIndex()).renderOutputFrame(renderTimeNs);
   }
 }

libraries/effect/src/main/java/androidx/media3/effect/SingleInputVideoGraph.java

@@ -16,11 +16,14 @@
 
 package androidx.media3.effect;
 
+import static androidx.media3.common.util.Assertions.checkArgument;
 import static androidx.media3.common.util.Assertions.checkState;
 import static androidx.media3.common.util.Assertions.checkStateNotNull;
 
 import android.content.Context;
+import androidx.annotation.IntRange;
 import androidx.annotation.Nullable;
+import androidx.media3.common.C;
 import androidx.media3.common.ColorInfo;
 import androidx.media3.common.DebugViewProvider;
 import androidx.media3.common.Effect;
@@ -38,9 +41,6 @@
 @UnstableApi
 public abstract class SingleInputVideoGraph implements VideoGraph {
 
-  /** The index of the only {@linkplain #registerInput(int) registered} input. */
-  public static final int SINGLE_INPUT_INDEX = 0;
-
   private final Context context;
   private final VideoFrameProcessor.Factory videoFrameProcessorFactory;
   private final ColorInfo outputColorInfo;
@@ -56,6 +56,7 @@ public abstract class SingleInputVideoGraph implements VideoGraph {
   private boolean isEnded;
   private boolean released;
   private volatile boolean hasProducedFrameWithTimestampZero;
+  private int inputIndex;
 
   /**
    * Creates an instance.
@@ -86,6 +87,7 @@ public SingleInputVideoGraph(
     this.renderFramesAutomatically = renderFramesAutomatically;
     this.presentation = presentation;
     this.initialTimestampOffsetUs = initialTimestampOffsetUs;
+    this.inputIndex = C.INDEX_UNSET;
   }
 
   /**
@@ -99,9 +101,11 @@ public void initialize() {
   }
 
   @Override
-  public void registerInput(int sequenceIndex) throws VideoFrameProcessingException {
+  public void registerInput(int inputIndex) throws VideoFrameProcessingException {
     checkStateNotNull(videoFrameProcessor == null && !released);
+    checkState(this.inputIndex == C.INDEX_UNSET);
 
+    this.inputIndex = inputIndex;
     videoFrameProcessor =
         videoFrameProcessorFactory.create(
             context,
@@ -162,7 +166,8 @@ public void onEnded() {
   }
 
   @Override
-  public VideoFrameProcessor getProcessor(int sequenceIndex) {
+  public VideoFrameProcessor getProcessor(int inputIndex) {
+    checkArgument(this.inputIndex != C.INDEX_UNSET && this.inputIndex == inputIndex);
     return checkStateNotNull(videoFrameProcessor);
   }
 
@@ -192,6 +197,10 @@ public void release() {
     released = true;
   }
 
+  protected int getInputIndex() {
+    return inputIndex;
+  }
+
   protected long getInitialTimestampOffsetUs() {
     return initialTimestampOffsetUs;
   }

libraries/effect/src/main/java/androidx/media3/effect/VideoCompositor.java

@@ -15,6 +15,7 @@
  */
 package androidx.media3.effect;
 
+import androidx.annotation.IntRange;
 import androidx.media3.common.ColorInfo;
 import androidx.media3.common.GlTextureInfo;
 import androidx.media3.common.VideoFrameProcessingException;
@@ -48,29 +49,33 @@ interface Listener {
   /**
    * Registers a new input source.
    *
-   * @param sequenceIndex The sequence index of the input source which is used to determine the
-   *     order of the input sources. The same index should to be used in {@link #queueInputTexture}.
+   * @param inputIndex The index of the input source which could be used to determine the order of
+   *     the input sources. The same index should to be used in {@link #queueInputTexture}. The
+   *     index must start from 0. All inputs must be registered before
+   *     {@linkplain #queueInputTexture(int, GlTextureProducer, GlTextureInfo, ColorInfo, long) queueing}
+   *     textures.
    */
-  void registerInputSource(int sequenceIndex);
+  void registerInputSource(@IntRange(from = 0) int inputIndex);
 
   /**
    * Signals that no more frames will come from the upstream {@link GlTextureProducer.Listener}.
    *
-   * @param inputId The identifier for an input source, returned from {@link #registerInputSource}.
+   * @param inputIndex The index of the input source.
    */
-  void signalEndOfInputSource(int inputId);
+  void signalEndOfInputSource(int inputIndex);
 
   /**
    * Queues an input texture to be composited.
    *
-   * @param inputId The identifier for an input source, returned from {@link #registerInputSource}.
+   * @param inputIndex The index of the input source, the same index used when {@linkplain
+   *     #registerInputSource(int) registering the input source}.
    * @param textureProducer The source from where the {@code inputTexture} is produced.
    * @param inputTexture The {@link GlTextureInfo} to composite.
    * @param colorInfo The {@link ColorInfo} of {@code inputTexture}.
    * @param presentationTimeUs The presentation time of {@code inputTexture}, in microseconds.
    */
   void queueInputTexture(
-      int inputId,
+      int inputIndex,
       GlTextureProducer textureProducer,
       GlTextureInfo inputTexture,
       ColorInfo colorInfo,