Replace Transformer.Muxer interface with Muxer.Muxer

PiperOrigin-RevId: 633193701

RELEASENOTES.md

@@ -32,6 +32,9 @@
         at stereo when handling PCM input.
     *   When selecting tracks in `ExoPlayerAssetLoader`, ignore audio channel
         count constraints as they only apply for playback.
+    *   Replace `androidx.media3.transformer.Muxer` interface with
+        `androidx.media3.muxer.Muxer` and remove
+        `androidx.media3.transformer.Muxer`.
 *   Track Selection:
 *   Extractors:
     *   MPEG-TS: Roll forward the change ensuring the last frame is rendered by

demos/transformer/build.gradle

@@ -83,6 +83,7 @@ dependencies {
     implementation project(modulePrefix + 'lib-exoplayer')
     implementation project(modulePrefix + 'lib-exoplayer-dash')
     implementation project(modulePrefix + 'lib-transformer')
+    implementation project(modulePrefix + 'lib-muxer')
     implementation project(modulePrefix + 'lib-ui')
 
     // For MediaPipe and its dependencies:

demos/transformer/src/main/java/androidx/media3/demo/transformer/TransformerActivity.java

@@ -80,6 +80,7 @@ import androidx.media3.effect.TextureOverlay;
 import androidx.media3.exoplayer.ExoPlayer;
 import androidx.media3.exoplayer.audio.SilenceSkippingAudioProcessor;
 import androidx.media3.exoplayer.util.DebugTextViewHelper;
+import androidx.media3.muxer.Muxer;
 import androidx.media3.transformer.Composition;
 import androidx.media3.transformer.DefaultEncoderFactory;
 import androidx.media3.transformer.DefaultMuxer;
@@ -90,7 +91,6 @@ import androidx.media3.transformer.ExportException;
 import androidx.media3.transformer.ExportResult;
 import androidx.media3.transformer.InAppMuxer;
 import androidx.media3.transformer.JsonUtil;
-import androidx.media3.transformer.Muxer;
 import androidx.media3.transformer.ProgressHolder;
 import androidx.media3.transformer.Transformer;
 import androidx.media3.ui.AspectRatioFrameLayout;

libraries/muxer/src/androidTest/java/androidx/media3/muxer/AndroidMuxerTestUtil.java

@@ -19,6 +19,7 @@ import android.content.Context;
 import android.media.MediaCodec;
 import android.media.MediaExtractor;
 import androidx.media3.common.util.MediaFormatUtil;
+import androidx.media3.muxer.Muxer.MuxerException;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
@@ -37,7 +38,7 @@ import java.util.List;
   }
 
   public static void feedInputDataToMuxer(Context context, Muxer muxer, String inputFileName)
-      throws IOException {
+      throws IOException, MuxerException {
     MediaExtractor extractor = new MediaExtractor();
     extractor.setDataSource(
         context.getResources().getAssets().openFd(MP4_FILE_ASSET_DIRECTORY + inputFileName));

libraries/muxer/src/androidTest/java/androidx/media3/muxer/FragmentedMp4MuxerEndToEndAndroidTest.java

@@ -62,7 +62,7 @@ public class FragmentedMp4MuxerEndToEndAndroidTest {
   }
 
   @Test
-  public void createFragmentedMp4File_fromInputFileSampleData_matchesExpected() throws IOException {
+  public void createFragmentedMp4File_fromInputFileSampleData_matchesExpected() throws Exception {
     @Nullable Muxer fragmentedMp4Muxer = null;
 
     try {
@@ -89,7 +89,7 @@ public class FragmentedMp4MuxerEndToEndAndroidTest {
 
   @Test
   public void createFragmentedMp4File_fromInputFileSampleData_matchesExpectedBoxStructure()
-      throws IOException {
+      throws Exception {
     @Nullable Muxer fragmentedMp4Muxer = null;
 
     try {

libraries/muxer/src/androidTest/java/androidx/media3/muxer/Mp4MuxerEndToEndAndroidTest.java

@@ -73,7 +73,7 @@ public class Mp4MuxerEndToEndAndroidTest {
   }
 
   @Test
-  public void createMp4File_fromInputFileSampleData_matchesExpected() throws IOException {
+  public void createMp4File_fromInputFileSampleData_matchesExpected() throws Exception {
     @Nullable Mp4Muxer mp4Muxer = null;
 
     try {
@@ -96,7 +96,7 @@ public class Mp4MuxerEndToEndAndroidTest {
   }
 
   @Test
-  public void createMp4File_muxerNotClosed_createsPartiallyWrittenValidFile() throws IOException {
+  public void createMp4File_muxerNotClosed_createsPartiallyWrittenValidFile() throws Exception {
     // Skip for all parameter values except when the input is a large file. The muxer writes samples
     // in batches (and flushes data only when it's closed), so a large input file is needed to
     // ensure some data has been written after taking all the inputs but before closing the muxer.

libraries/muxer/src/main/java/androidx/media3/muxer/FragmentedMp4Muxer.java

@@ -156,12 +156,21 @@ public final class FragmentedMp4Muxer implements Muxer {
    *     Builder#setSampleCopyEnabled(boolean) sample copying} is disabled. Otherwise, the position
    *     of the buffer is updated but the caller retains ownership.
    * @param bufferInfo The {@link BufferInfo} related to this sample.
-   * @throws IOException If there is any error while writing data to the disk.
+   * @throws MuxerException If there is any error while writing data to the disk.
    */
   @Override
   public void writeSampleData(TrackToken trackToken, ByteBuffer byteBuffer, BufferInfo bufferInfo)
-      throws IOException {
-    fragmentedMp4Writer.writeSampleData(trackToken, byteBuffer, bufferInfo);
+      throws MuxerException {
+    try {
+      fragmentedMp4Writer.writeSampleData(trackToken, byteBuffer, bufferInfo);
+    } catch (IOException e) {
+      throw new MuxerException(
+          "Failed to write sample for presentationTimeUs="
+              + bufferInfo.presentationTimeUs
+              + ", size="
+              + bufferInfo.size,
+          e);
+    }
   }
 
   /**
@@ -190,7 +199,11 @@ public final class FragmentedMp4Muxer implements Muxer {
   }
 
   @Override
-  public void close() throws IOException {
-    fragmentedMp4Writer.close();
+  public void close() throws MuxerException {
+    try {
+      fragmentedMp4Writer.close();
+    } catch (IOException e) {
+      throw new MuxerException("Failed to close the muxer", e);
+    }
   }
 }

libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Muxer.java

@@ -221,12 +221,21 @@ public final class Mp4Muxer implements Muxer {
    *     Builder#setSampleCopyEnabled(boolean) sample copying} is disabled. Otherwise, the position
    *     of the buffer is updated but the caller retains ownership.
    * @param bufferInfo The {@link BufferInfo} related to this sample.
-   * @throws IOException If there is any error while writing data to the disk.
+   * @throws MuxerException If there is any error while writing data to the disk.
    */
   @Override
   public void writeSampleData(TrackToken trackToken, ByteBuffer byteBuffer, BufferInfo bufferInfo)
-      throws IOException {
-    mp4Writer.writeSampleData(trackToken, byteBuffer, bufferInfo);
+      throws MuxerException {
+    try {
+      mp4Writer.writeSampleData(trackToken, byteBuffer, bufferInfo);
+    } catch (IOException e) {
+      throw new MuxerException(
+          "Failed to write sample for presentationTimeUs="
+              + bufferInfo.presentationTimeUs
+              + ", size="
+              + bufferInfo.size,
+          e);
+    }
   }
 
   /**
@@ -255,7 +264,11 @@ public final class Mp4Muxer implements Muxer {
   }
 
   @Override
-  public void close() throws IOException {
-    mp4Writer.close();
+  public void close() throws MuxerException {
+    try {
+      mp4Writer.close();
+    } catch (IOException e) {
+      throw new MuxerException("Failed to close the muxer", e);
+    }
   }
 }

libraries/muxer/src/main/java/androidx/media3/muxer/Muxer.java

@@ -16,28 +16,81 @@
 package androidx.media3.muxer;
 
 import android.media.MediaCodec.BufferInfo;
+import androidx.media3.common.C;
 import androidx.media3.common.Format;
 import androidx.media3.common.Metadata;
+import androidx.media3.common.MimeTypes;
 import androidx.media3.common.util.UnstableApi;
-import java.io.IOException;
+import com.google.common.collect.ImmutableList;
 import java.nio.ByteBuffer;
 
 /** The muxer for producing media container files. */
 @UnstableApi
 public interface Muxer {
+  /** Thrown when a muxer failure occurs. */
+  final class MuxerException extends Exception {
+    /**
+     * Creates an instance.
+     *
+     * @param message See {@link #getMessage()}.
+     * @param cause See {@link #getCause()}.
+     */
+    public MuxerException(String message, Throwable cause) {
+      super(message, cause);
+    }
+  }
+
+  /** Factory for muxers. */
+  interface Factory {
+    /**
+     * Returns a new {@link Muxer}.
+     *
+     * @param path The path to the output file.
+     * @throws MuxerException If an error occurs opening the output file for writing.
+     */
+    Muxer create(String path) throws MuxerException;
+
+    /**
+     * Returns the supported sample {@linkplain MimeTypes MIME types} for the given {@link
+     * C.TrackType}.
+     */
+    ImmutableList<String> getSupportedSampleMimeTypes(@C.TrackType int trackType);
+  }
+
   /** A token representing an added track. */
   interface TrackToken {}
 
-  /** Adds a track of the given media format. */
-  TrackToken addTrack(Format format);
+  /**
+   * Adds a track of the given media format.
+   *
+   * @param format The {@link Format} of the track.
+   * @return The {@link TrackToken} for this track, which should be passed to {@link
+   *     #writeSampleData}.
+   * @throws MuxerException If the muxer encounters a problem while adding the track.
+   */
+  TrackToken addTrack(Format format) throws MuxerException;
 
-  /** Writes encoded sample data. */
+  /**
+   * Writes encoded sample data.
+   *
+   * @param trackToken The {@link TrackToken} of the track, previously returned by {@link
+   *     #addTrack(Format)}.
+   * @param byteBuffer A buffer containing the sample data to write to the container.
+   * @param bufferInfo The {@link BufferInfo} of the sample.
+   * @throws MuxerException If the muxer fails to write the sample.
+   */
   void writeSampleData(TrackToken trackToken, ByteBuffer byteBuffer, BufferInfo bufferInfo)
-      throws IOException;
+      throws MuxerException;
 
   /** Adds {@linkplain Metadata.Entry metadata} about the output file. */
   void addMetadataEntry(Metadata.Entry metadataEntry);
 
-  /** Closes the file. */
-  void close() throws IOException;
+  /**
+   * Closes the file.
+   *
+   * <p>The muxer cannot be used anymore once this method returns.
+   *
+   * @throws MuxerException If the muxer fails to finish writing the output.
+   */
+  void close() throws MuxerException;
 }

libraries/muxer/src/test/java/androidx/media3/muxer/Mp4MuxerEndToEndTest.java

@@ -39,7 +39,6 @@ import androidx.media3.test.utils.TestUtil;
 import androidx.test.core.app.ApplicationProvider;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import java.io.FileOutputStream;
-import java.io.IOException;
 import java.nio.ByteBuffer;
 import org.junit.Rule;
 import org.junit.Test;
@@ -54,7 +53,7 @@ public class Mp4MuxerEndToEndTest {
   private final Context context = ApplicationProvider.getApplicationContext();
 
   @Test
-  public void createMp4File_addTrackAndMetadataButNoSamples_createsEmptyFile() throws IOException {
+  public void createMp4File_addTrackAndMetadataButNoSamples_createsEmptyFile() throws Exception {
     String outputFilePath = temporaryFolder.newFile().getPath();
     Mp4Muxer mp4Muxer = new Mp4Muxer.Builder(new FileOutputStream(outputFilePath)).build();
 
@@ -75,7 +74,7 @@ public class Mp4MuxerEndToEndTest {
   }
 
   @Test
-  public void createMp4File_withSameTracksOffset_matchesExpected() throws IOException {
+  public void createMp4File_withSameTracksOffset_matchesExpected() throws Exception {
     String outputFilePath = temporaryFolder.newFile().getPath();
     Mp4Muxer mp4Muxer = new Mp4Muxer.Builder(new FileOutputStream(outputFilePath)).build();
     mp4Muxer.addMetadataEntry(
@@ -118,7 +117,7 @@ public class Mp4MuxerEndToEndTest {
   }
 
   @Test
-  public void createMp4File_withDifferentTracksOffset_matchesExpected() throws IOException {
+  public void createMp4File_withDifferentTracksOffset_matchesExpected() throws Exception {
     String outputFilePath = temporaryFolder.newFile().getPath();
     Mp4Muxer mp4Muxer = new Mp4Muxer.Builder(new FileOutputStream(outputFilePath)).build();
     mp4Muxer.addMetadataEntry(
@@ -157,7 +156,7 @@ public class Mp4MuxerEndToEndTest {
   }
 
   @Test
-  public void writeSampleData_withOutOfOrderSampleTimestamps_throws() throws IOException {
+  public void writeSampleData_withOutOfOrderSampleTimestamps_throws() throws Exception {
     String outputFilePath = temporaryFolder.newFile().getPath();
     Mp4Muxer mp4Muxer = new Mp4Muxer.Builder(new FileOutputStream(outputFilePath)).build();
     Pair<ByteBuffer, BufferInfo> track1Sample1 =

libraries/transformer/src/androidTest/java/androidx/media3/transformer/TransformerPauseResumeTest.java

@@ -36,7 +36,8 @@ import androidx.media3.common.audio.AudioProcessor;
 import androidx.media3.common.audio.SonicAudioProcessor;
 import androidx.media3.common.util.Util;
 import androidx.media3.effect.RgbFilter;
-import androidx.media3.muxer.Muxer.TrackToken;
+import androidx.media3.muxer.Muxer;
+import androidx.media3.muxer.Muxer.MuxerException;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import androidx.test.platform.app.InstrumentationRegistry;
 import com.google.common.base.Ascii;
@@ -418,7 +419,7 @@ public class TransformerPauseResumeTest {
     }
 
     @Override
-    public Muxer create(String path) throws Muxer.MuxerException {
+    public Muxer create(String path) throws MuxerException {
       return new FrameBlockingMuxer(wrappedMuxerFactory.create(path), listener);
     }
 
@@ -473,8 +474,8 @@ public class TransformerPauseResumeTest {
     }
 
     @Override
-    public void release() throws MuxerException {
-      wrappedMuxer.release();
+    public void close() throws MuxerException {
+      wrappedMuxer.close();
     }
   }
 }

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

@@ -20,6 +20,7 @@ import androidx.media3.common.C;
 import androidx.media3.common.Format;
 import androidx.media3.common.Metadata;
 import androidx.media3.common.util.UnstableApi;
+import androidx.media3.muxer.Muxer;
 import androidx.media3.muxer.Muxer.TrackToken;
 import com.google.common.collect.ImmutableList;
 import java.nio.ByteBuffer;
@@ -71,9 +72,9 @@ public final class DefaultMuxer implements Muxer {
   }
 
   @Override
-  public void writeSampleData(TrackToken trackToken, ByteBuffer data, BufferInfo bufferInfo)
+  public void writeSampleData(TrackToken trackToken, ByteBuffer byteBuffer, BufferInfo bufferInfo)
       throws MuxerException {
-    muxer.writeSampleData(trackToken, data, bufferInfo);
+    muxer.writeSampleData(trackToken, byteBuffer, bufferInfo);
   }
 
   @Override
@@ -82,7 +83,7 @@ public final class DefaultMuxer implements Muxer {
   }
 
   @Override
-  public void release() throws MuxerException {
-    muxer.release();
+  public void close() throws MuxerException {
+    muxer.close();
   }
 }

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

@@ -32,7 +32,7 @@ import androidx.media3.common.MimeTypes;
 import androidx.media3.common.util.MediaFormatUtil;
 import androidx.media3.common.util.Util;
 import androidx.media3.container.Mp4LocationData;
-import androidx.media3.muxer.Muxer.TrackToken;
+import androidx.media3.muxer.Muxer;
 import com.google.common.collect.ImmutableList;
 import java.io.IOException;
 import java.lang.reflect.Field;
@@ -199,7 +199,7 @@ import java.util.Map;
   }
 
   @Override
-  public void release() throws MuxerException {
+  public void close() throws MuxerException {
     if (isReleased) {
       return;
     }

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

@@ -25,12 +25,12 @@ import androidx.media3.container.Mp4OrientationData;
 import androidx.media3.muxer.FragmentedMp4Muxer;
 import androidx.media3.muxer.Mp4Muxer;
 import androidx.media3.muxer.Mp4Utils;
+import androidx.media3.muxer.Muxer;
 import androidx.media3.muxer.Muxer.TrackToken;
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
-import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.LinkedHashSet;
 import java.util.Set;
@@ -170,7 +170,7 @@ public final class InAppMuxer implements Muxer {
   }
 
   @Override
-  public TrackToken addTrack(Format format) {
+  public TrackToken addTrack(Format format) throws MuxerException {
     TrackToken trackToken = muxer.addTrack(format);
     if (MimeTypes.isVideo(format.sampleMimeType)) {
       muxer.addMetadataEntry(new Mp4OrientationData(format.rotationDegrees));
@@ -179,19 +179,9 @@ public final class InAppMuxer implements Muxer {
   }
 
   @Override
-  public void writeSampleData(TrackToken trackToken, ByteBuffer data, BufferInfo bufferInfo)
+  public void writeSampleData(TrackToken trackToken, ByteBuffer byteBuffer, BufferInfo bufferInfo)
       throws MuxerException {
-
-    try {
-      muxer.writeSampleData(trackToken, data, bufferInfo);
-    } catch (IOException e) {
-      throw new MuxerException(
-          "Failed to write sample for presentationTimeUs="
-              + bufferInfo.presentationTimeUs
-              + ", size="
-              + bufferInfo.size,
-          e);
-    }
+    muxer.writeSampleData(trackToken, byteBuffer, bufferInfo);
   }
 
   @Override
@@ -202,14 +192,9 @@ public final class InAppMuxer implements Muxer {
   }
 
   @Override
-  public void release() throws MuxerException {
+  public void close() throws MuxerException {
     writeMetadata();
-
-    try {
-      muxer.close();
-    } catch (IOException e) {
-      throw new MuxerException("Error closing muxer", e);
-    }
+    muxer.close();
   }
 
   private void writeMetadata() {

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

@@ -1,106 +0,0 @@
-/*
- * Copyright 2021 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.media.MediaCodec.BufferInfo;
-import androidx.media3.common.C;
-import androidx.media3.common.Format;
-import androidx.media3.common.Metadata;
-import androidx.media3.common.MimeTypes;
-import androidx.media3.common.util.UnstableApi;
-import androidx.media3.muxer.Muxer.TrackToken;
-import com.google.common.collect.ImmutableList;
-import java.nio.ByteBuffer;
-
-/**
- * Abstracts media muxing operations.
- *
- * <p>Query whether {@linkplain Factory#getSupportedSampleMimeTypes(int) sample MIME types} are
- * supported and {@linkplain #addTrack(Format) add all tracks}, then {@linkplain #writeSampleData
- * write sample data} to mux samples. Once any sample data has been written, it is not possible to
- * add tracks. After writing all sample data, {@linkplain #release() release} the instance to finish
- * writing to the output and return any resources to the system.
- */
-@UnstableApi
-// TODO: b/330695864 - Replace with the Muxer interface from the Muxer module.
-public interface Muxer {
-
-  /** Thrown when a muxing failure occurs. */
-  final class MuxerException extends Exception {
-    /**
-     * Creates an instance.
-     *
-     * @param message See {@link #getMessage()}.
-     * @param cause See {@link #getCause()}.
-     */
-    public MuxerException(String message, Throwable cause) {
-      super(message, cause);
-    }
-  }
-
-  /** Factory for muxers. */
-  interface Factory {
-    /**
-     * Returns a new muxer writing to a file.
-     *
-     * @param path The path to the output file.
-     * @throws IllegalArgumentException If the path is invalid.
-     * @throws MuxerException If an error occurs opening the output file for writing.
-     */
-    Muxer create(String path) throws MuxerException;
-
-    /**
-     * Returns the supported sample {@linkplain MimeTypes MIME types} for the given {@link
-     * C.TrackType}.
-     */
-    ImmutableList<String> getSupportedSampleMimeTypes(@C.TrackType int trackType);
-  }
-
-  /**
-   * Adds a track with the specified format.
-   *
-   * @param format The {@link Format} of the track.
-   * @return The {@link TrackToken} for this track, which should be passed to {@link
-   *     #writeSampleData}.
-   * @throws MuxerException If the muxer encounters a problem while adding the track.
-   */
-  TrackToken addTrack(Format format) throws MuxerException;
-
-  /**
-   * Writes the specified sample.
-   *
-   * @param trackToken The {@link TrackToken} of the track, previously returned by {@link
-   *     #addTrack(Format)}.
-   * @param data A buffer containing the sample data to write to the container.
-   * @param bufferInfo The {@link BufferInfo} of the sample.
-   * @throws MuxerException If the muxer fails to write the sample.
-   */
-  void writeSampleData(TrackToken trackToken, ByteBuffer data, BufferInfo bufferInfo)
-      throws MuxerException;
-
-  /** Adds {@linkplain Metadata.Entry metadata} about the output file. */
-  void addMetadataEntry(Metadata.Entry metadataEntry);
-
-  /**
-   * Finishes writing the output and releases any resources associated with muxing.
-   *
-   * <p>The muxer cannot be used anymore once this method has been called.
-   *
-   * @throws MuxerException If the muxer fails to finish writing the output and {@code
-   *     forCancellation} is false.
-   */
-  void release() throws MuxerException;
-}

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

@@ -48,6 +48,8 @@ import androidx.media3.common.MimeTypes;
 import androidx.media3.common.util.Util;
 import androidx.media3.container.NalUnitUtil;
 import androidx.media3.effect.DebugTraceUtil;
+import androidx.media3.muxer.Muxer;
+import androidx.media3.muxer.Muxer.MuxerException;
 import androidx.media3.muxer.Muxer.TrackToken;
 import com.google.common.collect.ImmutableList;
 import java.io.File;
@@ -374,11 +376,10 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
    * @throws IllegalStateException If the number of formats added exceeds the {@linkplain
    *     #setTrackCount track count}, if {@link #setTrackCount(int)} has not been called or if there
    *     is already a track of that {@link C.TrackType}.
-   * @throws Muxer.MuxerException If the underlying {@link Muxer} encounters a problem while adding
-   *     the track.
+   * @throws MuxerException If the underlying {@link Muxer} encounters a problem while adding the
+   *     track.
    */
-  public void addTrackFormat(Format format)
-      throws AppendTrackFormatException, Muxer.MuxerException {
+  public void addTrackFormat(Format format) throws AppendTrackFormatException, MuxerException {
     @Nullable String sampleMimeType = format.sampleMimeType;
     @C.TrackType int trackType = MimeTypes.getTrackType(sampleMimeType);
     checkArgument(
@@ -521,11 +522,11 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
    *     received a format} for every {@linkplain #setTrackCount(int) track}.
    * @throws IllegalArgumentException If the muxer doesn't have a {@linkplain #endTrack(int)
    *     non-ended} track of the given {@link C.TrackType}.
-   * @throws Muxer.MuxerException If the underlying {@link Muxer} fails to write the sample.
+   * @throws MuxerException If the underlying {@link Muxer} fails to write the sample.
    */
   public boolean writeSample(
       @C.TrackType int trackType, ByteBuffer data, boolean isKeyFrame, long presentationTimeUs)
-      throws Muxer.MuxerException {
+      throws MuxerException {
     checkArgument(contains(trackTypeToInfo, trackType));
     TrackInfo trackInfo = trackTypeToInfo.get(trackType);
     boolean canWriteSample = canWriteSample(trackType, presentationTimeUs);
@@ -653,11 +654,11 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
    * #MUXER_RELEASE_REASON_CANCELLED} or {@link #MUXER_RELEASE_REASON_ERROR}.
    *
    * @param releaseReason The reason to release the muxer.
-   * @throws Muxer.MuxerException If the underlying {@link Muxer} fails to finish writing the output
-   *     and the {@code releaseReason} is not {@link #MUXER_RELEASE_REASON_CANCELLED}.
+   * @throws MuxerException If the underlying {@link Muxer} fails to finish writing the output and
+   *     the {@code releaseReason} is not {@link #MUXER_RELEASE_REASON_CANCELLED}.
    */
   public void finishWritingAndMaybeRelease(@MuxerReleaseReason int releaseReason)
-      throws Muxer.MuxerException {
+      throws MuxerException {
     if (releaseReason == MUXER_RELEASE_REASON_COMPLETED && muxerMode == MUXER_MODE_MUX_PARTIAL) {
       return;
     }
@@ -665,8 +666,8 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     abortScheduledExecutorService.shutdownNow();
     if (muxer != null) {
       try {
-        muxer.release();
-      } catch (Muxer.MuxerException e) {
+        muxer.close();
+      } catch (MuxerException e) {
         if (releaseReason == MUXER_RELEASE_REASON_CANCELLED
             && checkNotNull(e.getMessage())
                 .equals(FrameworkMuxer.MUXER_STOPPING_FAILED_ERROR_MESSAGE)) {
@@ -736,7 +737,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   }
 
   @EnsuresNonNull("muxer")
-  private void ensureMuxerInitialized() throws Muxer.MuxerException {
+  private void ensureMuxerInitialized() throws MuxerException {
     if (muxer == null) {
       muxer = muxerFactory.create(outputPath);
     }

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

@@ -30,6 +30,7 @@ import androidx.media3.common.Format;
 import androidx.media3.common.Metadata;
 import androidx.media3.common.MimeTypes;
 import androidx.media3.decoder.DecoderInputBuffer;
+import androidx.media3.muxer.Muxer.MuxerException;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import java.util.List;
@@ -110,7 +111,7 @@ import java.util.List;
       }
       try {
         muxerWrapper.addTrackFormat(inputFormat);
-      } catch (Muxer.MuxerException e) {
+      } catch (MuxerException e) {
         throw ExportException.createForMuxer(e, ExportException.ERROR_CODE_MUXING_FAILED);
       } catch (MuxerWrapper.AppendTrackFormatException e) {
         throw ExportException.createForMuxer(e, ExportException.ERROR_CODE_MUXING_APPEND);
@@ -136,7 +137,7 @@ import java.util.List;
           muxerInputBuffer.timeUs)) {
         return false;
       }
-    } catch (Muxer.MuxerException e) {
+    } catch (MuxerException e) {
       throw ExportException.createForMuxer(e, ExportException.ERROR_CODE_MUXING_FAILED);
     }
 

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

@@ -59,6 +59,7 @@ import androidx.media3.effect.DebugTraceUtil;
 import androidx.media3.effect.DefaultVideoFrameProcessor;
 import androidx.media3.effect.Presentation;
 import androidx.media3.exoplayer.source.DefaultMediaSourceFactory;
+import androidx.media3.muxer.Muxer;
 import com.google.common.collect.ImmutableList;
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;

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

@@ -62,6 +62,7 @@ import androidx.media3.common.util.Clock;
 import androidx.media3.common.util.ConditionVariable;
 import androidx.media3.common.util.HandlerWrapper;
 import androidx.media3.common.util.Util;
+import androidx.media3.muxer.Muxer.MuxerException;
 import androidx.media3.transformer.AssetLoader.CompositionSettings;
 import com.google.common.collect.ImmutableList;
 import java.lang.annotation.Documented;
@@ -436,7 +437,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       }
       try {
         muxerWrapper.finishWritingAndMaybeRelease(getMuxerReleaseReason(endReason));
-      } catch (Muxer.MuxerException e) {
+      } catch (MuxerException e) {
         if (releaseExportException == null) {
           releaseExportException = ExportException.createForMuxer(e, ERROR_CODE_MUXING_FAILED);
         }

libraries/transformer/src/test/java/androidx/media3/transformer/CapturingMuxer.java

@@ -26,7 +26,7 @@ import androidx.media3.common.C;
 import androidx.media3.common.Format;
 import androidx.media3.common.Metadata;
 import androidx.media3.common.util.Util;
-import androidx.media3.muxer.Muxer.TrackToken;
+import androidx.media3.muxer.Muxer;
 import androidx.media3.test.utils.DumpableFormat;
 import androidx.media3.test.utils.Dumper;
 import androidx.media3.test.utils.Dumper.Dumpable;
@@ -72,7 +72,7 @@ public final class CapturingMuxer implements Muxer, Dumpable {
     }
 
     @Override
-    public Muxer create(String path) throws Muxer.MuxerException {
+    public Muxer create(String path) throws MuxerException {
       muxer = new CapturingMuxer(wrappedFactory.create(path), handleAudioAsPcm);
       return muxer;
     }
@@ -142,9 +142,9 @@ public final class CapturingMuxer implements Muxer, Dumpable {
   }
 
   @Override
-  public void release() throws MuxerException {
+  public void close() throws MuxerException {
     released = true;
-    wrappedMuxer.release();
+    wrappedMuxer.close();
   }
 
   // Dumper.Dumpable implementation.

libraries/transformer/src/test/java/androidx/media3/transformer/MuxerWrapperTest.java

@@ -30,6 +30,7 @@ import androidx.annotation.Nullable;
 import androidx.media3.common.C;
 import androidx.media3.common.ColorInfo;
 import androidx.media3.common.Format;
+import androidx.media3.muxer.Muxer.MuxerException;
 import androidx.media3.test.utils.DumpFileAsserts;
 import androidx.test.core.app.ApplicationProvider;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
@@ -74,7 +75,7 @@ public class MuxerWrapperTest {
   @Nullable private MuxerWrapper muxerWrapper;
 
   @After
-  public void tearDown() throws Muxer.MuxerException {
+  public void tearDown() throws MuxerException {
     if (muxerWrapper != null) {
       // Release with reason cancellation so that underlying resources are always released.
       muxerWrapper.finishWritingAndMaybeRelease(MuxerWrapper.MUXER_RELEASE_REASON_CANCELLED);

libraries/transformer/src/test/java/androidx/media3/transformer/TestUtil.java

@@ -24,6 +24,7 @@ import androidx.media3.common.audio.ChannelMixingMatrix;
 import androidx.media3.common.audio.SonicAudioProcessor;
 import androidx.media3.common.util.UnstableApi;
 import androidx.media3.common.util.Util;
+import androidx.media3.muxer.Muxer;
 import androidx.media3.test.utils.FakeClock;
 import androidx.test.core.app.ApplicationProvider;
 import com.google.common.collect.ImmutableList;

libraries/transformer/src/test/java/androidx/media3/transformer/TransformerWithInAppMuxerEndToEndTest.java

@@ -34,6 +34,7 @@ import androidx.media3.container.Mp4TimestampData;
 import androidx.media3.container.XmpData;
 import androidx.media3.extractor.mp4.Mp4Extractor;
 import androidx.media3.extractor.text.DefaultSubtitleParserFactory;
+import androidx.media3.muxer.Muxer;
 import androidx.media3.test.utils.DumpFileAsserts;
 import androidx.media3.test.utils.FakeClock;
 import androidx.media3.test.utils.FakeExtractorOutput;