Trim CodecDelay/PreSkip In New OpusDecoder Instances By Default

PiperOrigin-RevId: 427819209

libraries/decoder_opus/src/main/java/androidx/media3/decoder/opus/OpusDecoder.java

@@ -99,6 +99,7 @@ public final class OpusDecoder
     }
     preSkipSamples = getPreSkipSamples(initializationData);
     seekPreRollSamples = getSeekPreRollSamples(initializationData);
+    skipSamples = preSkipSamples;
 
     byte[] headerBytes = initializationData.get(0);
     if (headerBytes.length < 19) {

libraries/decoder_opus/src/test/java/androidx/media3/decoder/opus/OpusDecoderTest.java

@@ -17,11 +17,16 @@ package androidx.media3.decoder.opus;
 
 import static com.google.common.truth.Truth.assertThat;
 
+import androidx.annotation.Nullable;
 import androidx.media3.common.C;
+import androidx.media3.common.util.LibraryLoader;
+import androidx.media3.decoder.DecoderInputBuffer;
+import androidx.media3.decoder.SimpleDecoderOutputBuffer;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.common.collect.ImmutableList;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -29,9 +34,14 @@ import org.junit.runner.RunWith;
 @RunWith(AndroidJUnit4.class)
 public final class OpusDecoderTest {
 
+  private static final LibraryLoader LOADER = new LibraryLoader("opusV2JNI");
+
   private static final byte[] HEADER =
       new byte[] {79, 112, 117, 115, 72, 101, 97, 100, 0, 2, 1, 56, 0, 0, -69, -128, 0, 0, 0};
 
+  private static final byte[] ENCODED_DATA = new byte[] {-4};
+  private static final int DECODED_DATA_SIZE = 3840;
+
   private static final int HEADER_PRE_SKIP_SAMPLES = 14337;
 
   private static final int DEFAULT_SEEK_PRE_ROLL_SAMPLES = 3840;
@@ -39,6 +49,7 @@ public final class OpusDecoderTest {
   private static final ImmutableList<byte[]> HEADER_ONLY_INITIALIZATION_DATA =
       ImmutableList.of(HEADER);
 
+  private static final long PRE_SKIP_NANOS = 6_500_000;
   private static final long CUSTOM_PRE_SKIP_SAMPLES = 28674;
   private static final byte[] CUSTOM_PRE_SKIP_BYTES =
       buildNativeOrderByteArray(sampleCountToNanoseconds(CUSTOM_PRE_SKIP_SAMPLES));
@@ -50,6 +61,11 @@ public final class OpusDecoderTest {
   private static final ImmutableList<byte[]> FULL_INITIALIZATION_DATA =
       ImmutableList.of(HEADER, CUSTOM_PRE_SKIP_BYTES, CUSTOM_SEEK_PRE_ROLL_BYTES);
 
+  @Before
+  public void setUp() {
+    assertThat(LOADER.isAvailable()).isTrue();
+  }
+
   @Test
   public void getChannelCount() {
     int channelCount = OpusDecoder.getChannelCount(HEADER);
@@ -80,11 +96,56 @@ public final class OpusDecoderTest {
     assertThat(seekPreRollSamples).isEqualTo(DEFAULT_SEEK_PRE_ROLL_SAMPLES);
   }
 
+  @Test
+  public void decode_removesPreSkipFromOutput() throws OpusDecoderException {
+    OpusDecoder decoder =
+        new OpusDecoder(
+            /* numInputBuffers= */ 0,
+            /* numOutputBuffers= */ 0,
+            /* initialInputBufferSize= */ 0,
+            createInitializationData(/* preSkipNanos= */ PRE_SKIP_NANOS),
+            /* cryptoConfig= */ null,
+            /* outputFloat= */ false);
+    DecoderInputBuffer input =
+        createInputBuffer(decoder, ENCODED_DATA, /* supplementalData= */ null);
+    SimpleDecoderOutputBuffer output = decoder.createOutputBuffer();
+    assertThat(decoder.decode(input, output, false)).isNull();
+    assertThat(output.data.remaining())
+        .isEqualTo(DECODED_DATA_SIZE - nanosecondsToBytes(PRE_SKIP_NANOS));
+  }
+
   private static long sampleCountToNanoseconds(long sampleCount) {
     return (sampleCount * C.NANOS_PER_SECOND) / OpusDecoder.SAMPLE_RATE;
   }
 
+  private static long nanosecondsToSampleCount(long nanoseconds) {
+    return (nanoseconds * OpusDecoder.SAMPLE_RATE) / C.NANOS_PER_SECOND;
+  }
+
+  private static long nanosecondsToBytes(long nanoseconds) {
+    return nanosecondsToSampleCount(nanoseconds) * 4;
+  }
+
   private static byte[] buildNativeOrderByteArray(long value) {
     return ByteBuffer.allocate(8).order(ByteOrder.nativeOrder()).putLong(value).array();
   }
+
+  private static ImmutableList<byte[]> createInitializationData(long preSkipNanos) {
+    byte[] preSkip = buildNativeOrderByteArray(preSkipNanos);
+    return ImmutableList.of(HEADER, preSkip, CUSTOM_SEEK_PRE_ROLL_BYTES);
+  }
+
+  private static DecoderInputBuffer createInputBuffer(
+      OpusDecoder decoder, byte[] data, @Nullable byte[] supplementalData) {
+    DecoderInputBuffer input = decoder.createInputBuffer();
+    input.ensureSpaceForWrite(data.length);
+    input.data.put(data);
+    input.data.position(0).limit(data.length);
+    if (supplementalData != null) {
+      input.resetSupplementalData(supplementalData.length);
+      input.supplementalData.put(supplementalData).rewind();
+      input.addFlag(C.BUFFER_FLAG_HAS_SUPPLEMENTAL_DATA);
+    }
+    return input;
+  }
 }