Make sure that the sample pipeline data is processed regularly.

This is necessary to move video decoding to the AssetLoader. Otherwise,
if the decoder max pending frame count is reached, the AssetLoader will
stop queuing frames to the pipeline, and process data will not be called
anymore.

PiperOrigin-RevId: 492392621

libraries/test_data/src/test/assets/transformerdumps/mkv/sample_with_srt.mkv.dump

@@ -14,6 +14,72 @@ format 1:
   initializationData:
     data = length 30, hash F6F3D010
     data = length 10, hash 7A0D0F2B
+sample:
+  trackIndex = 0
+  dataHashCode = 555688582
+  size = 416
+  isKeyFrame = true
+  presentationTimeUs = 0
+sample:
+  trackIndex = 0
+  dataHashCode = 2000837254
+  size = 418
+  isKeyFrame = true
+  presentationTimeUs = 4717
+sample:
+  trackIndex = 0
+  dataHashCode = -1593942879
+  size = 418
+  isKeyFrame = true
+  presentationTimeUs = 9456
+sample:
+  trackIndex = 0
+  dataHashCode = 587837542
+  size = 418
+  isKeyFrame = true
+  presentationTimeUs = 14196
+sample:
+  trackIndex = 0
+  dataHashCode = -1836423877
+  size = 418
+  isKeyFrame = true
+  presentationTimeUs = 18935
+sample:
+  trackIndex = 0
+  dataHashCode = 874705099
+  size = 418
+  isKeyFrame = true
+  presentationTimeUs = 23674
+sample:
+  trackIndex = 0
+  dataHashCode = -269206181
+  size = 418
+  isKeyFrame = true
+  presentationTimeUs = 28413
+sample:
+  trackIndex = 0
+  dataHashCode = -58682425
+  size = 418
+  isKeyFrame = true
+  presentationTimeUs = 33152
+sample:
+  trackIndex = 0
+  dataHashCode = -859796970
+  size = 418
+  isKeyFrame = true
+  presentationTimeUs = 37892
+sample:
+  trackIndex = 0
+  dataHashCode = 711911523
+  size = 418
+  isKeyFrame = true
+  presentationTimeUs = 42631
+sample:
+  trackIndex = 0
+  dataHashCode = -694513071
+  size = 418
+  isKeyFrame = true
+  presentationTimeUs = 47370
 sample:
   trackIndex = 1
   dataHashCode = -252482306
@@ -104,72 +170,6 @@ sample:
   size = 5525
   isKeyFrame = false
   presentationTimeUs = 567000
-sample:
-  trackIndex = 0
-  dataHashCode = 555688582
-  size = 416
-  isKeyFrame = true
-  presentationTimeUs = 0
-sample:
-  trackIndex = 0
-  dataHashCode = 2000837254
-  size = 418
-  isKeyFrame = true
-  presentationTimeUs = 4717
-sample:
-  trackIndex = 0
-  dataHashCode = -1593942879
-  size = 418
-  isKeyFrame = true
-  presentationTimeUs = 9456
-sample:
-  trackIndex = 0
-  dataHashCode = 587837542
-  size = 418
-  isKeyFrame = true
-  presentationTimeUs = 14196
-sample:
-  trackIndex = 0
-  dataHashCode = -1836423877
-  size = 418
-  isKeyFrame = true
-  presentationTimeUs = 18935
-sample:
-  trackIndex = 0
-  dataHashCode = 874705099
-  size = 418
-  isKeyFrame = true
-  presentationTimeUs = 23674
-sample:
-  trackIndex = 0
-  dataHashCode = -269206181
-  size = 418
-  isKeyFrame = true
-  presentationTimeUs = 28413
-sample:
-  trackIndex = 0
-  dataHashCode = -58682425
-  size = 418
-  isKeyFrame = true
-  presentationTimeUs = 33152
-sample:
-  trackIndex = 0
-  dataHashCode = -859796970
-  size = 418
-  isKeyFrame = true
-  presentationTimeUs = 37892
-sample:
-  trackIndex = 0
-  dataHashCode = 711911523
-  size = 418
-  isKeyFrame = true
-  presentationTimeUs = 42631
-sample:
-  trackIndex = 0
-  dataHashCode = -694513071
-  size = 418
-  isKeyFrame = true
-  presentationTimeUs = 47370
 sample:
   trackIndex = 0
   dataHashCode = -1124371059
@@ -200,6 +200,12 @@ sample:
   size = 418
   isKeyFrame = true
   presentationTimeUs = 71066
+sample:
+  trackIndex = 1
+  dataHashCode = -637074022
+  size = 1082
+  isKeyFrame = false
+  presentationTimeUs = 500000
 sample:
   trackIndex = 0
   dataHashCode = 1297086772
@@ -278,12 +284,6 @@ sample:
   size = 418
   isKeyFrame = true
   presentationTimeUs = 132676
-sample:
-  trackIndex = 1
-  dataHashCode = -637074022
-  size = 1082
-  isKeyFrame = false
-  presentationTimeUs = 500000
 sample:
   trackIndex = 1
   dataHashCode = -1824027029

libraries/test_data/src/test/assets/transformerdumps/mp4/sample.mp4.48000hz.dump

@@ -14,6 +14,78 @@ format 1:
   initializationData:
     data = length 29, hash 4746B5D9
     data = length 10, hash 7A0D0F2B
+sample:
+  trackIndex = 0
+  dataHashCode = 1868041800
+  size = 22
+  isKeyFrame = true
+  presentationTimeUs = 0
+sample:
+  trackIndex = 0
+  dataHashCode = 1552866193
+  size = 8
+  isKeyFrame = true
+  presentationTimeUs = 230
+sample:
+  trackIndex = 0
+  dataHashCode = 701848493
+  size = 160
+  isKeyFrame = true
+  presentationTimeUs = 313
+sample:
+  trackIndex = 0
+  dataHashCode = 2000505720
+  size = 206
+  isKeyFrame = true
+  presentationTimeUs = 1980
+sample:
+  trackIndex = 0
+  dataHashCode = 57276327
+  size = 222
+  isKeyFrame = true
+  presentationTimeUs = 4125
+sample:
+  trackIndex = 0
+  dataHashCode = 382237408
+  size = 228
+  isKeyFrame = true
+  presentationTimeUs = 6438
+sample:
+  trackIndex = 0
+  dataHashCode = 795308374
+  size = 228
+  isKeyFrame = true
+  presentationTimeUs = 8813
+sample:
+  trackIndex = 0
+  dataHashCode = 356270426
+  size = 224
+  isKeyFrame = true
+  presentationTimeUs = 11188
+sample:
+  trackIndex = 0
+  dataHashCode = 963641614
+  size = 244
+  isKeyFrame = true
+  presentationTimeUs = 13521
+sample:
+  trackIndex = 0
+  dataHashCode = 2045272193
+  size = 234
+  isKeyFrame = true
+  presentationTimeUs = 16063
+sample:
+  trackIndex = 0
+  dataHashCode = -251933090
+  size = 228
+  isKeyFrame = true
+  presentationTimeUs = 18500
+sample:
+  trackIndex = 0
+  dataHashCode = -329315280
+  size = 234
+  isKeyFrame = true
+  presentationTimeUs = 20875
 sample:
   trackIndex = 1
   dataHashCode = -770308242
@@ -104,78 +176,6 @@ sample:
   size = 5450
   isKeyFrame = false
   presentationTimeUs = 567233
-sample:
-  trackIndex = 0
-  dataHashCode = 1868041800
-  size = 22
-  isKeyFrame = true
-  presentationTimeUs = 0
-sample:
-  trackIndex = 0
-  dataHashCode = 1552866193
-  size = 8
-  isKeyFrame = true
-  presentationTimeUs = 230
-sample:
-  trackIndex = 0
-  dataHashCode = 701848493
-  size = 160
-  isKeyFrame = true
-  presentationTimeUs = 313
-sample:
-  trackIndex = 0
-  dataHashCode = 2000505720
-  size = 206
-  isKeyFrame = true
-  presentationTimeUs = 1980
-sample:
-  trackIndex = 0
-  dataHashCode = 57276327
-  size = 222
-  isKeyFrame = true
-  presentationTimeUs = 4125
-sample:
-  trackIndex = 0
-  dataHashCode = 382237408
-  size = 228
-  isKeyFrame = true
-  presentationTimeUs = 6438
-sample:
-  trackIndex = 0
-  dataHashCode = 795308374
-  size = 228
-  isKeyFrame = true
-  presentationTimeUs = 8813
-sample:
-  trackIndex = 0
-  dataHashCode = 356270426
-  size = 224
-  isKeyFrame = true
-  presentationTimeUs = 11188
-sample:
-  trackIndex = 0
-  dataHashCode = 963641614
-  size = 244
-  isKeyFrame = true
-  presentationTimeUs = 13521
-sample:
-  trackIndex = 0
-  dataHashCode = 2045272193
-  size = 234
-  isKeyFrame = true
-  presentationTimeUs = 16063
-sample:
-  trackIndex = 0
-  dataHashCode = -251933090
-  size = 228
-  isKeyFrame = true
-  presentationTimeUs = 18500
-sample:
-  trackIndex = 0
-  dataHashCode = -329315280
-  size = 234
-  isKeyFrame = true
-  presentationTimeUs = 20875
 sample:
   trackIndex = 0
   dataHashCode = -1536715689
@@ -284,6 +284,12 @@ sample:
   size = 250
   isKeyFrame = true
   presentationTimeUs = 67625
+sample:
+  trackIndex = 1
+  dataHashCode = -1830836678
+  size = 1051
+  isKeyFrame = false
+  presentationTimeUs = 500500
 sample:
   trackIndex = 0
   dataHashCode = -1290952882
@@ -374,12 +380,6 @@ sample:
   size = 8
   isKeyFrame = true
   presentationTimeUs = 107646
-sample:
-  trackIndex = 1
-  dataHashCode = -1830836678
-  size = 1051
-  isKeyFrame = false
-  presentationTimeUs = 500500
 sample:
   trackIndex = 1
   dataHashCode = 1767407540

libraries/test_data/src/test/assets/transformerdumps/mp4/sample.mp4.dump

@@ -21,6 +21,12 @@ format 1:
   initializationData:
     data = length 29, hash 4746B5D9
     data = length 10, hash 7A0D0F2B
+sample:
+  trackIndex = 0
+  dataHashCode = 1205768497
+  size = 23
+  isKeyFrame = true
+  presentationTimeUs = 44000
 sample:
   trackIndex = 1
   dataHashCode = -770308242
@@ -111,12 +117,6 @@ sample:
   size = 5450
   isKeyFrame = false
   presentationTimeUs = 567233
-sample:
-  trackIndex = 0
-  dataHashCode = 1205768497
-  size = 23
-  isKeyFrame = true
-  presentationTimeUs = 44000
 sample:
   trackIndex = 0
   dataHashCode = 837571078
@@ -129,6 +129,12 @@ sample:
   size = 148
   isKeyFrame = true
   presentationTimeUs = 90439
+sample:
+  trackIndex = 1
+  dataHashCode = -1830836678
+  size = 1051
+  isKeyFrame = false
+  presentationTimeUs = 500500
 sample:
   trackIndex = 0
   dataHashCode = -822987359
@@ -238,17 +244,41 @@ sample:
   isKeyFrame = true
   presentationTimeUs = 508399
 sample:
-  trackIndex = 1
+  trackIndex = 0
-  dataHashCode = -1830836678
+  dataHashCode = 1675188486
-  size = 1051
+  size = 228
-  isKeyFrame = false
+  isKeyFrame = true
-  presentationTimeUs = 500500
+  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 = 1
   dataHashCode = 1767407540
   size = 874
   isKeyFrame = false
   presentationTimeUs = 467133
+sample:
+  trackIndex = 0
+  dataHashCode = 1747388653
+  size = 217
+  isKeyFrame = true
+  presentationTimeUs = 624498
 sample:
   trackIndex = 1
   dataHashCode = 918440283
@@ -327,36 +357,6 @@ 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

libraries/test_data/src/test/assets/transformerdumps/mp4/sample_sef_slow_motion.mp4.dump

@@ -15,6 +15,78 @@ format 1:
   initializationData:
     data = length 33, hash D3FB879D
     data = length 10, hash 7A0D0F2B
+sample:
+  trackIndex = 0
+  dataHashCode = -212376212
+  size = 20
+  isKeyFrame = true
+  presentationTimeUs = 0
+sample:
+  trackIndex = 0
+  dataHashCode = -1948569090
+  size = 72
+  isKeyFrame = true
+  presentationTimeUs = 417
+sample:
+  trackIndex = 0
+  dataHashCode = -1316750072
+  size = 84
+  isKeyFrame = true
+  presentationTimeUs = 1917
+sample:
+  trackIndex = 0
+  dataHashCode = 1016428949
+  size = 88
+  isKeyFrame = true
+  presentationTimeUs = 3667
+sample:
+  trackIndex = 0
+  dataHashCode = -1127325245
+  size = 96
+  isKeyFrame = true
+  presentationTimeUs = 5500
+sample:
+  trackIndex = 0
+  dataHashCode = 1148147726
+  size = 92
+  isKeyFrame = true
+  presentationTimeUs = 7500
+sample:
+  trackIndex = 0
+  dataHashCode = -2125685540
+  size = 76
+  isKeyFrame = true
+  presentationTimeUs = 9417
+sample:
+  trackIndex = 0
+  dataHashCode = 473329679
+  size = 24
+  isKeyFrame = true
+  presentationTimeUs = 11000
+sample:
+  trackIndex = 0
+  dataHashCode = 240990900
+  size = 176
+  isKeyFrame = true
+  presentationTimeUs = 11500
+sample:
+  trackIndex = 0
+  dataHashCode = 777637182
+  size = 196
+  isKeyFrame = true
+  presentationTimeUs = 15167
+sample:
+  trackIndex = 0
+  dataHashCode = 1872106264
+  size = 180
+  isKeyFrame = true
+  presentationTimeUs = 19250
+sample:
+  trackIndex = 0
+  dataHashCode = -1520711499
+  size = 140
+  isKeyFrame = true
+  presentationTimeUs = 23000
 sample:
   trackIndex = 1
   dataHashCode = 1949079733
@@ -123,78 +195,6 @@ sample:
   size = 1109
   isKeyFrame = false
   presentationTimeUs = 600750
-sample:
-  trackIndex = 0
-  dataHashCode = -212376212
-  size = 20
-  isKeyFrame = true
-  presentationTimeUs = 0
-sample:
-  trackIndex = 0
-  dataHashCode = -1948569090
-  size = 72
-  isKeyFrame = true
-  presentationTimeUs = 417
-sample:
-  trackIndex = 0
-  dataHashCode = -1316750072
-  size = 84
-  isKeyFrame = true
-  presentationTimeUs = 1917
-sample:
-  trackIndex = 0
-  dataHashCode = 1016428949
-  size = 88
-  isKeyFrame = true
-  presentationTimeUs = 3667
-sample:
-  trackIndex = 0
-  dataHashCode = -1127325245
-  size = 96
-  isKeyFrame = true
-  presentationTimeUs = 5500
-sample:
-  trackIndex = 0
-  dataHashCode = 1148147726
-  size = 92
-  isKeyFrame = true
-  presentationTimeUs = 7500
-sample:
-  trackIndex = 0
-  dataHashCode = -2125685540
-  size = 76
-  isKeyFrame = true
-  presentationTimeUs = 9417
-sample:
-  trackIndex = 0
-  dataHashCode = 473329679
-  size = 24
-  isKeyFrame = true
-  presentationTimeUs = 11000
-sample:
-  trackIndex = 0
-  dataHashCode = 240990900
-  size = 176
-  isKeyFrame = true
-  presentationTimeUs = 11500
-sample:
-  trackIndex = 0
-  dataHashCode = 777637182
-  size = 196
-  isKeyFrame = true
-  presentationTimeUs = 15167
-sample:
-  trackIndex = 0
-  dataHashCode = 1872106264
-  size = 180
-  isKeyFrame = true
-  presentationTimeUs = 19250
-sample:
-  trackIndex = 0
-  dataHashCode = -1520711499
-  size = 140
-  isKeyFrame = true
-  presentationTimeUs = 23000
 sample:
   trackIndex = 0
   dataHashCode = 1580199067

libraries/test_data/src/test/assets/transformerdumps/mp4/sample_with_increasing_timestamps_320w_240h.mp4.clipped.dump

@@ -27,6 +27,12 @@ format 1:
   initializationData:
     data = length 31, hash 4B108214
     data = length 9, hash FBA158BB
+sample:
+  trackIndex = 0
+  dataHashCode = 620415738
+  size = 508
+  isKeyFrame = true
+  presentationTimeUs = 7020
 sample:
   trackIndex = 1
   dataHashCode = 983000500
@@ -219,18 +225,18 @@ sample:
   size = 151
   isKeyFrame = false
   presentationTimeUs = 516666
-sample:
-  trackIndex = 0
-  dataHashCode = 620415738
-  size = 508
-  isKeyFrame = true
-  presentationTimeUs = 7020
 sample:
   trackIndex = 0
   dataHashCode = 33931768
   size = 504
   isKeyFrame = true
   presentationTimeUs = 28354
+sample:
+  trackIndex = 1
+  dataHashCode = 264118578
+  size = 2235
+  isKeyFrame = false
+  presentationTimeUs = 533333
 sample:
   trackIndex = 0
   dataHashCode = 800699278
@@ -370,17 +376,23 @@ sample:
   isKeyFrame = true
   presentationTimeUs = 519020
 sample:
-  trackIndex = 1
+  trackIndex = 0
-  dataHashCode = 264118578
+  dataHashCode = 204379389
-  size = 2235
+  size = 504
-  isKeyFrame = false
+  isKeyFrame = true
-  presentationTimeUs = 533333
+  presentationTimeUs = 540354
 sample:
   trackIndex = 1
   dataHashCode = 64254117
   size = 164
   isKeyFrame = false
   presentationTimeUs = 550000
+sample:
+  trackIndex = 0
+  dataHashCode = 694913274
+  size = 508
+  isKeyFrame = true
+  presentationTimeUs = 561687
 sample:
   trackIndex = 1
   dataHashCode = -1000078879
@@ -556,23 +568,29 @@ sample:
   isKeyFrame = false
   presentationTimeUs = 1033333
 sample:
-  trackIndex = 0
+  trackIndex = 1
-  dataHashCode = 204379389
+  dataHashCode = 65238903
-  size = 504
+  size = 163
-  isKeyFrame = true
+  isKeyFrame = false
-  presentationTimeUs = 540354
+  presentationTimeUs = 1050000
 sample:
-  trackIndex = 0
+  trackIndex = 1
-  dataHashCode = 694913274
+  dataHashCode = 1720840922
-  size = 508
+  size = 2043
-  isKeyFrame = true
+  isKeyFrame = false
-  presentationTimeUs = 561687
+  presentationTimeUs = 1066666
 sample:
   trackIndex = 0
   dataHashCode = 289018778
   size = 513
   isKeyFrame = true
   presentationTimeUs = 583020
+sample:
+  trackIndex = 1
+  dataHashCode = -1006231050
+  size = 178
+  isKeyFrame = false
+  presentationTimeUs = 1083333
 sample:
   trackIndex = 0
   dataHashCode = -693167785
@@ -700,29 +718,35 @@ sample:
   isKeyFrame = true
   presentationTimeUs = 1031020
 sample:
-  trackIndex = 1
+  trackIndex = 0
-  dataHashCode = 65238903
+  dataHashCode = -320096195
-  size = 163
+  size = 509
-  isKeyFrame = false
+  isKeyFrame = true
-  presentationTimeUs = 1050000
+  presentationTimeUs = 1052354
 sample:
-  trackIndex = 1
+  trackIndex = 0
-  dataHashCode = 1720840922
+  dataHashCode = -744850549
-  size = 2043
+  size = 511
-  isKeyFrame = false
+  isKeyFrame = true
-  presentationTimeUs = 1066666
+  presentationTimeUs = 1073687
 sample:
-  trackIndex = 1
+  trackIndex = 0
-  dataHashCode = -1006231050
+  dataHashCode = 1457899387
-  size = 178
+  size = 505
-  isKeyFrame = false
+  isKeyFrame = true
-  presentationTimeUs = 1083333
+  presentationTimeUs = 1095020
 sample:
   trackIndex = 1
   dataHashCode = 1742965952
   size = 2022
   isKeyFrame = false
   presentationTimeUs = 1100000
+sample:
+  trackIndex = 0
+  dataHashCode = 168118808
+  size = 519
+  isKeyFrame = true
+  presentationTimeUs = 1116354
 sample:
   trackIndex = 1
   dataHashCode = -971065365
@@ -861,30 +885,6 @@ sample:
   size = 119
   isKeyFrame = false
   presentationTimeUs = 1483333
-sample:
-  trackIndex = 0
-  dataHashCode = -320096195
-  size = 509
-  isKeyFrame = true
-  presentationTimeUs = 1052354
-sample:
-  trackIndex = 0
-  dataHashCode = -744850549
-  size = 511
-  isKeyFrame = true
-  presentationTimeUs = 1073687
-sample:
-  trackIndex = 0
-  dataHashCode = 1457899387
-  size = 505
-  isKeyFrame = true
-  presentationTimeUs = 1095020
-sample:
-  trackIndex = 0
-  dataHashCode = 168118808
-  size = 519
-  isKeyFrame = true
-  presentationTimeUs = 1116354
 sample:
   trackIndex = 0
   dataHashCode = 896298799

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

@@ -17,7 +17,6 @@
 package androidx.media3.transformer;
 
 import static androidx.media3.common.util.Assertions.checkNotNull;
-import static androidx.media3.common.util.Assertions.checkStateNotNull;
 import static androidx.media3.transformer.TransformationException.ERROR_CODE_MUXING_FAILED;
 import static androidx.media3.transformer.Transformer.PROGRESS_STATE_AVAILABLE;
 import static androidx.media3.transformer.Transformer.PROGRESS_STATE_UNAVAILABLE;
@@ -91,7 +90,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   private static final int MSG_DRAIN_PIPELINES = 4;
   private static final int MSG_END = 5;
 
-  private static final int DRAIN_PIPELINES_DELAY_MS = 10;
+  private static final int DRAIN_PIPELINES_DELAY_MS = 50;
 
   private final Context context;
   private final TransformationRequest transformationRequest;
@@ -223,13 +222,13 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
           startInternal();
           break;
         case MSG_REGISTER_SAMPLE_PIPELINE:
-          samplePipelines.add((SamplePipeline) msg.obj);
+          registerSamplePipelineInternal((SamplePipeline) msg.obj);
           break;
         case MSG_DEQUEUE_INPUT:
           dequeueInputInternal(/* samplePipelineIndex= */ msg.arg1);
           break;
         case MSG_QUEUE_INPUT:
-          queueInputInternal(/* samplePipelineIndex= */ msg.arg1);
+          samplePipelines.get(/* samplePipelineIndex= */ msg.arg1).queueInputBuffer();
           break;
         case MSG_DRAIN_PIPELINES:
           drainPipelinesInternal();
@@ -254,12 +253,19 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     exoPlayerAssetLoader.start();
   }
 
+  private void registerSamplePipelineInternal(SamplePipeline samplePipeline) {
+    samplePipelines.add(samplePipeline);
+    if (!isDrainingPipelines) {
+      // Make sure pipelines are drained regularly to prevent them from getting stuck.
+      internalHandler.sendEmptyMessageDelayed(MSG_DRAIN_PIPELINES, DRAIN_PIPELINES_DELAY_MS);
+      isDrainingPipelines = true;
+    }
+  }
+
   private void dequeueInputInternal(int samplePipelineIndex) throws TransformationException {
     SamplePipeline samplePipeline = samplePipelines.get(samplePipelineIndex);
-    // The sample pipeline is drained before dequeuing input. It can't be done before queuing
+    // The sample pipeline is drained before dequeuing input to maximise the chances of having an
-    // input because, if the pipeline is full, dequeuing input would forever return a null buffer.
+    // input buffer to dequeue.
-    // Draining the pipeline at regular intervals would be inefficient because a low interval could
-    // result in many no-op operations, and a high interval could slow down data queuing.
     while (samplePipeline.processData()) {}
     pendingInputBuffer = samplePipeline.dequeueInputBuffer();
     dequeueBufferConditionVariable.open();
@@ -269,15 +275,6 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     }
   }
 
-  private void queueInputInternal(int samplePipelineIndex) throws TransformationException {
-    DecoderInputBuffer pendingInputBuffer = checkStateNotNull(this.pendingInputBuffer);
-    samplePipelines.get(samplePipelineIndex).queueInputBuffer();
-    if (pendingInputBuffer.isEndOfStream() && !isDrainingPipelines) {
-      internalHandler.sendEmptyMessageDelayed(MSG_DRAIN_PIPELINES, DRAIN_PIPELINES_DELAY_MS);
-      isDrainingPipelines = true;
-    }
-  }
-
   private void drainPipelinesInternal() throws TransformationException {
     for (int i = 0; i < samplePipelines.size(); i++) {
       while (samplePipelines.get(i).processData()) {}