Add PassthroughSamplePipeline for audio.

When no transformation is needed, the passthrough pipeline allows us to skip decoding and re-encoding.

PiperOrigin-RevId: 407789767

library/transformer/src/main/java/com/google/android/exoplayer2/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;

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

+/*
+ * 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 com.google.android.exoplayer2.transformer;
+
+import androidx.annotation.Nullable;
+import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.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() {}
+}

library/transformer/src/main/java/com/google/android/exoplayer2/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;
   }
 

testdata/src/test/assets/transformerdumps/mp4/sample.mp4.novideo.dump

 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