Add PassthroughSamplePipeline for audio.

When no transformation is needed, the passthrough pipeline allows us to skip decoding and re-encoding. PiperOrigin-RevId: 407789767
2026-04-06 11:25:46 +00:00 · 2021-11-05 11:13:26 +00:00 · 2021-11-05 11:13:26 +00:00 · 64466356b2
commit 64466356b2
parent 05c7a30bd7
6 changed files with 528 additions and 432 deletions
--- a/libraries/test_data/src/test/assets/transformerdumps/amr/sample_nb.amr.dump
+++ b/libraries/test_data/src/test/assets/transformerdumps/amr/sample_nb.amr.dump
--- a/libraries/test_data/src/test/assets/transformerdumps/mp4/sample.mp4.dump
+++ b/libraries/test_data/src/test/assets/transformerdumps/mp4/sample.mp4.dump
@ -1,9 +1,15 @@
 containerMimeType = video/mp4
 format 0:
+  id = 2
  sampleMimeType = audio/mp4a-latm
+  codecs = mp4a.40.2
+  maxInputSize = 294
  channelCount = 1
  sampleRate = 44100
-  pcmEncoding = 2
+  language = und
+  metadata = entries=[TSSE: description=null: value=Lavf56.1.0]
+  initializationData:
+    data = length 2, hash 5F7
 format 1:
  id = 1
  sampleMimeType = video/avc
@ -110,271 +116,127 @@ sample:
  dataHashCode = 1205768497
  size = 23
  isKeyFrame = true
-  presentationTimeUs = 0
+  presentationTimeUs = 44000
 sample:
  trackIndex = 0
  dataHashCode = 837571078
  size = 6
  isKeyFrame = true
-  presentationTimeUs = 249
+  presentationTimeUs = 67219
 sample:
  trackIndex = 0
  dataHashCode = -1991633045
  size = 148
  isKeyFrame = true
-  presentationTimeUs = 317
+  presentationTimeUs = 90439
 sample:
  trackIndex = 0
  dataHashCode = -822987359
  size = 189
  isKeyFrame = true
-  presentationTimeUs = 1995
+  presentationTimeUs = 113659
 sample:
  trackIndex = 0
  dataHashCode = -1141508176
  size = 205
  isKeyFrame = true
-  presentationTimeUs = 4126
+  presentationTimeUs = 136879
 sample:
  trackIndex = 0
  dataHashCode = -226971245
  size = 210
  isKeyFrame = true
-  presentationTimeUs = 6438
+  presentationTimeUs = 160099
 sample:
  trackIndex = 0
  dataHashCode = -2099636855
  size = 210
  isKeyFrame = true
-  presentationTimeUs = 8818
+  presentationTimeUs = 183319
 sample:
  trackIndex = 0
  dataHashCode = 1541550559
  size = 207
  isKeyFrame = true
-  presentationTimeUs = 11198
+  presentationTimeUs = 206539
 sample:
  trackIndex = 0
  dataHashCode = 411148001
  size = 225
  isKeyFrame = true
-  presentationTimeUs = 13533
+  presentationTimeUs = 229759
 sample:
  trackIndex = 0
  dataHashCode = -897603973
  size = 215
  isKeyFrame = true
-  presentationTimeUs = 16072
+  presentationTimeUs = 252979
 sample:
  trackIndex = 0
  dataHashCode = 1478106136
  size = 211
  isKeyFrame = true
-  presentationTimeUs = 18498
+  presentationTimeUs = 276199
 sample:
  trackIndex = 0
  dataHashCode = -1380417145
  size = 216
  isKeyFrame = true
-  presentationTimeUs = 20878
+  presentationTimeUs = 299419
 sample:
  trackIndex = 0
  dataHashCode = 780903644
  size = 229
  isKeyFrame = true
-  presentationTimeUs = 23326
+  presentationTimeUs = 322639
 sample:
  trackIndex = 0
  dataHashCode = 586204432
  size = 232
  isKeyFrame = true
-  presentationTimeUs = 25911
+  presentationTimeUs = 345859
 sample:
  trackIndex = 0
  dataHashCode = -2038771492
  size = 235
  isKeyFrame = true
-  presentationTimeUs = 28541
+  presentationTimeUs = 369079
 sample:
  trackIndex = 0
  dataHashCode = -2065161304
  size = 231
  isKeyFrame = true
-  presentationTimeUs = 31194
+  presentationTimeUs = 392299
 sample:
  trackIndex = 0
  dataHashCode = 468662933
  size = 226
  isKeyFrame = true
-  presentationTimeUs = 33801
+  presentationTimeUs = 415519
 sample:
  trackIndex = 0
  dataHashCode = -358398546
  size = 216
  isKeyFrame = true
-  presentationTimeUs = 36363
+  presentationTimeUs = 438739
 sample:
  trackIndex = 0
  dataHashCode = 1767325983
  size = 229
  isKeyFrame = true
-  presentationTimeUs = 38811
+  presentationTimeUs = 461959
 sample:
  trackIndex = 0
  dataHashCode = 1093095458
  size = 219
  isKeyFrame = true
-  presentationTimeUs = 41396
+  presentationTimeUs = 485179
 sample:
  trackIndex = 0
  dataHashCode = 1687543702
  size = 241
  isKeyFrame = true
-  presentationTimeUs = 43867
-sample:
-  trackIndex = 0
-  dataHashCode = 1675188486
-  size = 228
-  isKeyFrame = true
-  presentationTimeUs = 46588
-sample:
-  trackIndex = 0
-  dataHashCode = 888567545
-  size = 238
-  isKeyFrame = true
-  presentationTimeUs = 49173
-sample:
-  trackIndex = 0
-  dataHashCode = -439631803
-  size = 234
-  isKeyFrame = true
-  presentationTimeUs = 51871
-sample:
-  trackIndex = 0
-  dataHashCode = 1606694497
-  size = 231
-  isKeyFrame = true
-  presentationTimeUs = 54524
-sample:
-  trackIndex = 0
-  dataHashCode = 1747388653
-  size = 217
-  isKeyFrame = true
-  presentationTimeUs = 57131
-sample:
-  trackIndex = 0
-  dataHashCode = -734560004
-  size = 239
-  isKeyFrame = true
-  presentationTimeUs = 59579
-sample:
-  trackIndex = 0
-  dataHashCode = -975079040
-  size = 243
-  isKeyFrame = true
-  presentationTimeUs = 62277
-sample:
-  trackIndex = 0
-  dataHashCode = -1403504710
-  size = 231
-  isKeyFrame = true
-  presentationTimeUs = 65020
-sample:
-  trackIndex = 0
-  dataHashCode = 379512981
-  size = 230
-  isKeyFrame = true
-  presentationTimeUs = 67627
-sample:
-  trackIndex = 0
-  dataHashCode = -997198863
-  size = 238
-  isKeyFrame = true
-  presentationTimeUs = 70234
-sample:
-  trackIndex = 0
-  dataHashCode = 1394492825
-  size = 225
-  isKeyFrame = true
-  presentationTimeUs = 72932
-sample:
-  trackIndex = 0
-  dataHashCode = -885232755
-  size = 232
-  isKeyFrame = true
-  presentationTimeUs = 75471
-sample:
-  trackIndex = 0
-  dataHashCode = 260871367
-  size = 243
-  isKeyFrame = true
-  presentationTimeUs = 78101
-sample:
-  trackIndex = 0
-  dataHashCode = -1505318960
-  size = 232
-  isKeyFrame = true
-  presentationTimeUs = 80844
-sample:
-  trackIndex = 0
-  dataHashCode = -390625371
-  size = 237
-  isKeyFrame = true
-  presentationTimeUs = 83474
-sample:
-  trackIndex = 0
-  dataHashCode = 1067950751
-  size = 228
-  isKeyFrame = true
-  presentationTimeUs = 86149
-sample:
-  trackIndex = 0
-  dataHashCode = -1179436278
-  size = 235
-  isKeyFrame = true
-  presentationTimeUs = 88734
-sample:
-  trackIndex = 0
-  dataHashCode = 1906607774
-  size = 264
-  isKeyFrame = true
-  presentationTimeUs = 91387
-sample:
-  trackIndex = 0
-  dataHashCode = -800475828
-  size = 257
-  isKeyFrame = true
-  presentationTimeUs = 94380
-sample:
-  trackIndex = 0
-  dataHashCode = 1718972977
-  size = 227
-  isKeyFrame = true
-  presentationTimeUs = 97282
-sample:
-  trackIndex = 0
-  dataHashCode = -1120448741
-  size = 227
-  isKeyFrame = true
-  presentationTimeUs = 99844
-sample:
-  trackIndex = 0
-  dataHashCode = -1718323210
-  size = 235
-  isKeyFrame = true
-  presentationTimeUs = 102406
-sample:
-  trackIndex = 0
-  dataHashCode = -422416
-  size = 229
-  isKeyFrame = true
-  presentationTimeUs = 105059
-sample:
-  trackIndex = 0
-  dataHashCode = 833757830
-  size = 6
-  isKeyFrame = true
-  presentationTimeUs = 107644
+  presentationTimeUs = 508399
 sample:
  trackIndex = 1
  dataHashCode = -1830836678
@ -465,4 +327,148 @@ sample:
  size = 568
  isKeyFrame = false
  presentationTimeUs = 934266
+sample:
+  trackIndex = 0
+  dataHashCode = 1675188486
+  size = 228
+  isKeyFrame = true
+  presentationTimeUs = 531619
+sample:
+  trackIndex = 0
+  dataHashCode = 888567545
+  size = 238
+  isKeyFrame = true
+  presentationTimeUs = 554839
+sample:
+  trackIndex = 0
+  dataHashCode = -439631803
+  size = 234
+  isKeyFrame = true
+  presentationTimeUs = 578058
+sample:
+  trackIndex = 0
+  dataHashCode = 1606694497
+  size = 231
+  isKeyFrame = true
+  presentationTimeUs = 601278
+sample:
+  trackIndex = 0
+  dataHashCode = 1747388653
+  size = 217
+  isKeyFrame = true
+  presentationTimeUs = 624498
+sample:
+  trackIndex = 0
+  dataHashCode = -734560004
+  size = 239
+  isKeyFrame = true
+  presentationTimeUs = 647718
+sample:
+  trackIndex = 0
+  dataHashCode = -975079040
+  size = 243
+  isKeyFrame = true
+  presentationTimeUs = 670938
+sample:
+  trackIndex = 0
+  dataHashCode = -1403504710
+  size = 231
+  isKeyFrame = true
+  presentationTimeUs = 694158
+sample:
+  trackIndex = 0
+  dataHashCode = 379512981
+  size = 230
+  isKeyFrame = true
+  presentationTimeUs = 717378
+sample:
+  trackIndex = 0
+  dataHashCode = -997198863
+  size = 238
+  isKeyFrame = true
+  presentationTimeUs = 740598
+sample:
+  trackIndex = 0
+  dataHashCode = 1394492825
+  size = 225
+  isKeyFrame = true
+  presentationTimeUs = 763818
+sample:
+  trackIndex = 0
+  dataHashCode = -885232755
+  size = 232
+  isKeyFrame = true
+  presentationTimeUs = 787038
+sample:
+  trackIndex = 0
+  dataHashCode = 260871367
+  size = 243
+  isKeyFrame = true
+  presentationTimeUs = 810258
+sample:
+  trackIndex = 0
+  dataHashCode = -1505318960
+  size = 232
+  isKeyFrame = true
+  presentationTimeUs = 833478
+sample:
+  trackIndex = 0
+  dataHashCode = -390625371
+  size = 237
+  isKeyFrame = true
+  presentationTimeUs = 856698
+sample:
+  trackIndex = 0
+  dataHashCode = 1067950751
+  size = 228
+  isKeyFrame = true
+  presentationTimeUs = 879918
+sample:
+  trackIndex = 0
+  dataHashCode = -1179436278
+  size = 235
+  isKeyFrame = true
+  presentationTimeUs = 903138
+sample:
+  trackIndex = 0
+  dataHashCode = 1906607774
+  size = 264
+  isKeyFrame = true
+  presentationTimeUs = 926358
+sample:
+  trackIndex = 0
+  dataHashCode = -800475828
+  size = 257
+  isKeyFrame = true
+  presentationTimeUs = 949578
+sample:
+  trackIndex = 0
+  dataHashCode = 1718972977
+  size = 227
+  isKeyFrame = true
+  presentationTimeUs = 972798
+sample:
+  trackIndex = 0
+  dataHashCode = -1120448741
+  size = 227
+  isKeyFrame = true
+  presentationTimeUs = 996018
+sample:
+  trackIndex = 0
+  dataHashCode = -1718323210
+  size = 235
+  isKeyFrame = true
+  presentationTimeUs = 1019238
+sample:
+  trackIndex = 0
+  dataHashCode = -422416
+  size = 229
+  isKeyFrame = true
+  presentationTimeUs = 1042458
+sample:
+  trackIndex = 0
+  dataHashCode = 833757830
+  size = 6
+  isKeyFrame = true
+  presentationTimeUs = 1065678
 released = true
--- a/libraries/test_data/src/test/assets/transformerdumps/mp4/sample.mp4.novideo.dump
+++ b/libraries/test_data/src/test/assets/transformerdumps/mp4/sample.mp4.novideo.dump
@ -1,277 +1,283 @@
 containerMimeType = video/mp4
 format 0:
+  id = 2
  sampleMimeType = audio/mp4a-latm
+  codecs = mp4a.40.2
+  maxInputSize = 294
  channelCount = 1
  sampleRate = 44100
-  pcmEncoding = 2
+  language = und
+  metadata = entries=[TSSE: description=null: value=Lavf56.1.0]
+  initializationData:
+    data = length 2, hash 5F7
 sample:
  trackIndex = 0
  dataHashCode = 1205768497
  size = 23
  isKeyFrame = true
-  presentationTimeUs = 0
+  presentationTimeUs = 44000
 sample:
  trackIndex = 0
  dataHashCode = 837571078
  size = 6
  isKeyFrame = true
-  presentationTimeUs = 249
+  presentationTimeUs = 67219
 sample:
  trackIndex = 0
  dataHashCode = -1991633045
  size = 148
  isKeyFrame = true
-  presentationTimeUs = 317
+  presentationTimeUs = 90439
 sample:
  trackIndex = 0
  dataHashCode = -822987359
  size = 189
  isKeyFrame = true
-  presentationTimeUs = 1995
+  presentationTimeUs = 113659
 sample:
  trackIndex = 0
  dataHashCode = -1141508176
  size = 205
  isKeyFrame = true
-  presentationTimeUs = 4126
+  presentationTimeUs = 136879
 sample:
  trackIndex = 0
  dataHashCode = -226971245
  size = 210
  isKeyFrame = true
-  presentationTimeUs = 6438
+  presentationTimeUs = 160099
 sample:
  trackIndex = 0
  dataHashCode = -2099636855
  size = 210
  isKeyFrame = true
-  presentationTimeUs = 8818
+  presentationTimeUs = 183319
 sample:
  trackIndex = 0
  dataHashCode = 1541550559
  size = 207
  isKeyFrame = true
-  presentationTimeUs = 11198
+  presentationTimeUs = 206539
 sample:
  trackIndex = 0
  dataHashCode = 411148001
  size = 225
  isKeyFrame = true
-  presentationTimeUs = 13533
+  presentationTimeUs = 229759
 sample:
  trackIndex = 0
  dataHashCode = -897603973
  size = 215
  isKeyFrame = true
-  presentationTimeUs = 16072
+  presentationTimeUs = 252979
 sample:
  trackIndex = 0
  dataHashCode = 1478106136
  size = 211
  isKeyFrame = true
-  presentationTimeUs = 18498
+  presentationTimeUs = 276199
 sample:
  trackIndex = 0
  dataHashCode = -1380417145
  size = 216
  isKeyFrame = true
-  presentationTimeUs = 20878
+  presentationTimeUs = 299419
 sample:
  trackIndex = 0
  dataHashCode = 780903644
  size = 229
  isKeyFrame = true
-  presentationTimeUs = 23326
+  presentationTimeUs = 322639
 sample:
  trackIndex = 0
  dataHashCode = 586204432
  size = 232
  isKeyFrame = true
-  presentationTimeUs = 25911
+  presentationTimeUs = 345859
 sample:
  trackIndex = 0
  dataHashCode = -2038771492
  size = 235
  isKeyFrame = true
-  presentationTimeUs = 28541
+  presentationTimeUs = 369079
 sample:
  trackIndex = 0
  dataHashCode = -2065161304
  size = 231
  isKeyFrame = true
-  presentationTimeUs = 31194
+  presentationTimeUs = 392299
 sample:
  trackIndex = 0
  dataHashCode = 468662933
  size = 226
  isKeyFrame = true
-  presentationTimeUs = 33801
+  presentationTimeUs = 415519
 sample:
  trackIndex = 0
  dataHashCode = -358398546
  size = 216
  isKeyFrame = true
-  presentationTimeUs = 36363
+  presentationTimeUs = 438739
 sample:
  trackIndex = 0
  dataHashCode = 1767325983
  size = 229
  isKeyFrame = true
-  presentationTimeUs = 38811
+  presentationTimeUs = 461959
 sample:
  trackIndex = 0
  dataHashCode = 1093095458
  size = 219
  isKeyFrame = true
-  presentationTimeUs = 41396
+  presentationTimeUs = 485179
 sample:
  trackIndex = 0
  dataHashCode = 1687543702
  size = 241
  isKeyFrame = true
-  presentationTimeUs = 43867
+  presentationTimeUs = 508399
 sample:
  trackIndex = 0
  dataHashCode = 1675188486
  size = 228
  isKeyFrame = true
-  presentationTimeUs = 46588
+  presentationTimeUs = 531619
 sample:
  trackIndex = 0
  dataHashCode = 888567545
  size = 238
  isKeyFrame = true
-  presentationTimeUs = 49173
+  presentationTimeUs = 554839
 sample:
  trackIndex = 0
  dataHashCode = -439631803
  size = 234
  isKeyFrame = true
-  presentationTimeUs = 51871
+  presentationTimeUs = 578058
 sample:
  trackIndex = 0
  dataHashCode = 1606694497
  size = 231
  isKeyFrame = true
-  presentationTimeUs = 54524
+  presentationTimeUs = 601278
 sample:
  trackIndex = 0
  dataHashCode = 1747388653
  size = 217
  isKeyFrame = true
-  presentationTimeUs = 57131
+  presentationTimeUs = 624498
 sample:
  trackIndex = 0
  dataHashCode = -734560004
  size = 239
  isKeyFrame = true
-  presentationTimeUs = 59579
+  presentationTimeUs = 647718
 sample:
  trackIndex = 0
  dataHashCode = -975079040
  size = 243
  isKeyFrame = true
-  presentationTimeUs = 62277
+  presentationTimeUs = 670938
 sample:
  trackIndex = 0
  dataHashCode = -1403504710
  size = 231
  isKeyFrame = true
-  presentationTimeUs = 65020
+  presentationTimeUs = 694158
 sample:
  trackIndex = 0
  dataHashCode = 379512981
  size = 230
  isKeyFrame = true
-  presentationTimeUs = 67627
+  presentationTimeUs = 717378
 sample:
  trackIndex = 0
  dataHashCode = -997198863
  size = 238
  isKeyFrame = true
-  presentationTimeUs = 70234
+  presentationTimeUs = 740598
 sample:
  trackIndex = 0
  dataHashCode = 1394492825
  size = 225
  isKeyFrame = true
-  presentationTimeUs = 72932
+  presentationTimeUs = 763818
 sample:
  trackIndex = 0
  dataHashCode = -885232755
  size = 232
  isKeyFrame = true
-  presentationTimeUs = 75471
+  presentationTimeUs = 787038
 sample:
  trackIndex = 0
  dataHashCode = 260871367
  size = 243
  isKeyFrame = true
-  presentationTimeUs = 78101
+  presentationTimeUs = 810258
 sample:
  trackIndex = 0
  dataHashCode = -1505318960
  size = 232
  isKeyFrame = true
-  presentationTimeUs = 80844
+  presentationTimeUs = 833478
 sample:
  trackIndex = 0
  dataHashCode = -390625371
  size = 237
  isKeyFrame = true
-  presentationTimeUs = 83474
+  presentationTimeUs = 856698
 sample:
  trackIndex = 0
  dataHashCode = 1067950751
  size = 228
  isKeyFrame = true
-  presentationTimeUs = 86149
+  presentationTimeUs = 879918
 sample:
  trackIndex = 0
  dataHashCode = -1179436278
  size = 235
  isKeyFrame = true
-  presentationTimeUs = 88734
+  presentationTimeUs = 903138
 sample:
  trackIndex = 0
  dataHashCode = 1906607774
  size = 264
  isKeyFrame = true
-  presentationTimeUs = 91387
+  presentationTimeUs = 926358
 sample:
  trackIndex = 0
  dataHashCode = -800475828
  size = 257
  isKeyFrame = true
-  presentationTimeUs = 94380
+  presentationTimeUs = 949578
 sample:
  trackIndex = 0
  dataHashCode = 1718972977
  size = 227
  isKeyFrame = true
-  presentationTimeUs = 97282
+  presentationTimeUs = 972798
 sample:
  trackIndex = 0
  dataHashCode = -1120448741
  size = 227
  isKeyFrame = true
-  presentationTimeUs = 99844
+  presentationTimeUs = 996018
 sample:
  trackIndex = 0
  dataHashCode = -1718323210
  size = 235
  isKeyFrame = true
-  presentationTimeUs = 102406
+  presentationTimeUs = 1019238
 sample:
  trackIndex = 0
  dataHashCode = -422416
  size = 229
  isKeyFrame = true
-  presentationTimeUs = 105059
+  presentationTimeUs = 1042458
 sample:
  trackIndex = 0
  dataHashCode = 833757830
  size = 6
  isKeyFrame = true
-  presentationTimeUs = 107644
+  presentationTimeUs = 1065678
 released = true
--- a/libraries/transformer/src/main/java/androidx/media3/transformer/AudioSamplePipeline.java
+++ b/libraries/transformer/src/main/java/androidx/media3/transformer/AudioSamplePipeline.java
@ -366,6 +366,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
        errorCode);
  }

+  // TODO(internal b/204978301): Ensure encoder and decoder timestamps match when no speed change.
  private static long getBufferDurationUs(long bytesWritten, int bytesPerFrame, int sampleRate) {
    long framesWritten = bytesWritten / bytesPerFrame;
    return framesWritten * C.MICROS_PER_SECOND / sampleRate;
--- a/libraries/transformer/src/main/java/androidx/media3/transformer/PassthroughSamplePipeline.java
+++ b/libraries/transformer/src/main/java/androidx/media3/transformer/PassthroughSamplePipeline.java
@ -0,0 +1,77 @@
+/*
+ * 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 androidx.annotation.Nullable;
+import androidx.media3.common.Format;
+import androidx.media3.decoder.DecoderInputBuffer;
+
+/** Pipeline that passes through the samples without any re-encoding or transformation. */
+/* package */ final class PassthroughSamplePipeline implements SamplePipeline {
+
+  private final DecoderInputBuffer buffer;
+  private final Format format;
+
+  private boolean hasPendingBuffer;
+
+  public PassthroughSamplePipeline(Format format) {
+    this.format = format;
+    buffer = new DecoderInputBuffer(DecoderInputBuffer.BUFFER_REPLACEMENT_MODE_DIRECT);
+    hasPendingBuffer = false;
+  }
+
+  @Override
+  @Nullable
+  public DecoderInputBuffer dequeueInputBuffer() {
+    return hasPendingBuffer ? null : buffer;
+  }
+
+  @Override
+  public void queueInputBuffer() {
+    hasPendingBuffer = true;
+  }
+
+  @Override
+  public boolean processData() {
+    return false;
+  }
+
+  @Override
+  public Format getOutputFormat() {
+    return format;
+  }
+
+  @Override
+  @Nullable
+  public DecoderInputBuffer getOutputBuffer() {
+    return hasPendingBuffer ? buffer : null;
+  }
+
+  @Override
+  public void releaseOutputBuffer() {
+    buffer.clear();
+    hasPendingBuffer = false;
+  }
+
+  @Override
+  public boolean isEnded() {
+    return buffer.isEndOfStream();
+  }
+
+  @Override
+  public void release() {}
+}
--- a/libraries/transformer/src/main/java/androidx/media3/transformer/TransformerAudioRenderer.java
+++ b/libraries/transformer/src/main/java/androidx/media3/transformer/TransformerAudioRenderer.java
@ -89,8 +89,14 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
    if (result != C.RESULT_FORMAT_READ) {
      return false;
    }
-    samplePipeline =
-        new AudioSamplePipeline(checkNotNull(formatHolder.format), transformation, getIndex());
+    Format decoderInputFormat = checkNotNull(formatHolder.format);
+    if ((transformation.audioMimeType != null
+            && !transformation.audioMimeType.equals(decoderInputFormat.sampleMimeType))
+        || transformation.flattenForSlowMotion) {
+      samplePipeline = new AudioSamplePipeline(decoderInputFormat, transformation, getIndex());
+    } else {
+      samplePipeline = new PassthroughSamplePipeline(decoderInputFormat);
+    }
    return true;
  }