Add support for passing custom metadata via transformer

Changes included:
1. Enable MP4 extractor to read all types of metadata.
2. Allow passing String and Float metadata via Transformer.

Reference to QuickTime spec: https://developer.apple.com/library/archive/documentation/QuickTime/QTFF/Metadata/Metadata.html#//apple_ref/doc/uid/TP40000939-CH1-SW21

PiperOrigin-RevId: 538783982

libraries/common/src/main/java/androidx/media3/common/util/Util.java

@@ -27,6 +27,7 @@ import static androidx.media3.common.Player.COMMAND_SEEK_TO_NEXT;
 import static androidx.media3.common.Player.COMMAND_SEEK_TO_NEXT_MEDIA_ITEM;
 import static androidx.media3.common.Player.COMMAND_SEEK_TO_PREVIOUS;
 import static androidx.media3.common.Player.COMMAND_SEEK_TO_PREVIOUS_MEDIA_ITEM;
+import static androidx.media3.common.util.Assertions.checkArgument;
 import static androidx.media3.common.util.Assertions.checkNotNull;
 import static java.lang.Math.abs;
 import static java.lang.Math.max;
@@ -206,8 +207,16 @@ public final class Util {
     return outputStream.toByteArray();
   }
 
+  /** Converts an integer into an equivalent byte array. */
+  @UnstableApi
+  public static byte[] toByteArray(int value) {
+    return new byte[] {
+      (byte) (value >> 24), (byte) (value >> 16), (byte) (value >> 8), (byte) value
+    };
+  }
+
   /**
-   * Converts an array of 32-bit integers into an equivalent byte array.
+   * Converts an array of integers into an equivalent byte array.
    *
    * <p>Each integer is converted into 4 sequential bytes.
    */
@@ -216,14 +225,37 @@ public final class Util {
     byte[] array = new byte[values.length * 4];
     int index = 0;
     for (int value : values) {
-      array[index++] = (byte) (value >> 24);
+      byte[] byteArray = toByteArray(value);
-      array[index++] = (byte) (value >> 16);
+      array[index++] = byteArray[0];
-      array[index++] = (byte) (value >> 8);
+      array[index++] = byteArray[1];
-      array[index++] = (byte) (value /* >> 0 */);
+      array[index++] = byteArray[2];
+      array[index++] = byteArray[3];
     }
     return array;
   }
 
+  /** Converts a float into an equivalent byte array. */
+  @UnstableApi
+  public static byte[] toByteArray(float value) {
+    return toByteArray(Float.floatToIntBits(value));
+  }
+
+  /** Converts a byte array into a float. */
+  @UnstableApi
+  public static float toFloat(byte[] bytes) {
+    checkArgument(bytes.length == 4);
+    int intBits =
+        bytes[0] << 24 | (bytes[1] & 0xFF) << 16 | (bytes[2] & 0xFF) << 8 | (bytes[3] & 0xFF);
+    return Float.intBitsToFloat(intBits);
+  }
+
+  /** Converts a byte array into an integer. */
+  @UnstableApi
+  public static int toInteger(byte[] bytes) {
+    checkArgument(bytes.length == 4);
+    return bytes[0] << 24 | bytes[1] << 16 | bytes[2] << 8 | bytes[3];
+  }
+
   /**
    * Registers a {@link BroadcastReceiver} that's not intended to receive broadcasts from other
    * apps. This will be enforced by specifying {@link Context#RECEIVER_NOT_EXPORTED} if {@link
@@ -463,7 +495,7 @@ public final class Util {
   @UnstableApi
   @SuppressWarnings({"nullness:argument", "nullness:return"})
   public static <T> T[] nullSafeArrayCopy(T[] input, int length) {
-    Assertions.checkArgument(length <= input.length);
+    checkArgument(length <= input.length);
     return Arrays.copyOf(input, length);
   }
 
@@ -478,8 +510,8 @@ public final class Util {
   @UnstableApi
   @SuppressWarnings({"nullness:argument", "nullness:return"})
   public static <T> T[] nullSafeArrayCopyOfRange(T[] input, int from, int to) {
-    Assertions.checkArgument(0 <= from);
+    checkArgument(0 <= from);
-    Assertions.checkArgument(to <= input.length);
+    checkArgument(to <= input.length);
     return Arrays.copyOfRange(input, from, to);
   }
 
@@ -1609,7 +1641,7 @@ public final class Util {
   @UnstableApi
   public static int getIntegerCodeForString(String string) {
     int length = string.length();
-    Assertions.checkArgument(length <= 4);
+    checkArgument(length <= 4);
     int result = 0;
     for (int i = 0; i < length; i++) {
       result <<= 8;

libraries/container/src/main/java/androidx/media3/container/MdtaMetadataEntry.java

@@ -21,7 +21,6 @@ import androidx.annotation.Nullable;
 import androidx.media3.common.Metadata;
 import androidx.media3.common.util.UnstableApi;
 import androidx.media3.common.util.Util;
-import java.nio.ByteBuffer;
 import java.util.Arrays;
 
 /**
@@ -34,7 +33,12 @@ public final class MdtaMetadataEntry implements Metadata.Entry {
   /** Key for the capture frame rate (in frames per second). */
   public static final String KEY_ANDROID_CAPTURE_FPS = "com.android.capture.fps";
 
-  public static final int TYPE_INDICATOR_FLOAT = 23;
+  /** The type indicator for UTF-8 string. */
+  public static final int TYPE_INDICATOR_STRING = 1;
+  /** The type indicator for Float32. */
+  public static final int TYPE_INDICATOR_FLOAT32 = 23;
+  /** The type indicator for 32-bit signed integer. */
+  public static final int TYPE_INDICATOR_INT32 = 67;
 
   /** The metadata key name. */
   public final String key;
@@ -87,10 +91,21 @@ public final class MdtaMetadataEntry implements Metadata.Entry {
 
   @Override
   public String toString() {
-    String formattedValue =
+    String formattedValue;
-        typeIndicator == TYPE_INDICATOR_FLOAT
+    switch (typeIndicator) {
-            ? Float.toString(ByteBuffer.wrap(value).getFloat())
+      case TYPE_INDICATOR_STRING:
-            : Util.toHexString(value);
+        formattedValue = Util.fromUtf8Bytes(value);
+        break;
+      case TYPE_INDICATOR_FLOAT32:
+        formattedValue = String.valueOf(Util.toFloat(value));
+        break;
+      case TYPE_INDICATOR_INT32:
+        formattedValue = String.valueOf(Util.toInteger(value));
+        break;
+      default:
+        formattedValue = Util.toHexString(value);
+    }
+
     return "mdta: key=" + key + ", value=" + formattedValue;
   }
 

libraries/exoplayer/src/test/java/androidx/media3/exoplayer/MetadataRetrieverTest.java

@@ -26,6 +26,7 @@ import android.net.Uri;
 import androidx.media3.common.C;
 import androidx.media3.common.MediaItem;
 import androidx.media3.common.MimeTypes;
+import androidx.media3.common.util.Util;
 import androidx.media3.container.CreationTime;
 import androidx.media3.container.MdtaMetadataEntry;
 import androidx.media3.exoplayer.source.TrackGroupArray;
@@ -153,6 +154,18 @@ public class MetadataRetrieverTest {
   public void retrieveMetadata_sefSlowMotion_outputsExpectedMetadata() throws Exception {
     MediaItem mediaItem =
         MediaItem.fromUri(Uri.parse("asset://android_asset/media/mp4/sample_sef_slow_motion.mp4"));
+    MdtaMetadataEntry expectedAndroidVersionMetadata =
+        new MdtaMetadataEntry(
+            /* key= */ "com.android.version",
+            /* value= */ Util.getUtf8Bytes("10"),
+            /* localeIndicator= */ 0,
+            MdtaMetadataEntry.TYPE_INDICATOR_STRING);
+    MdtaMetadataEntry expectedTemporalLayersCountMetdata =
+        new MdtaMetadataEntry(
+            /* key= */ "com.android.video.temporal_layers_count",
+            /* value= */ Util.toByteArray(4),
+            /* localeIndicator= */ 0,
+            MdtaMetadataEntry.TYPE_INDICATOR_INT32);
     SmtaMetadataEntry expectedSmtaEntry =
         new SmtaMetadataEntry(/* captureFrameRate= */ 240, /* svcTemporalLayerCount= */ 4);
     List<SlowMotionData.Segment> segments = new ArrayList<>();
@@ -178,17 +191,25 @@ public class MetadataRetrieverTest {
 
     assertThat(trackGroups.length).isEqualTo(2); // Video and audio
     // Audio
-    assertThat(trackGroups.get(0).getFormat(0).metadata.length()).isEqualTo(3);
+    assertThat(trackGroups.get(0).getFormat(0).metadata.length()).isEqualTo(5);
-    assertThat(trackGroups.get(0).getFormat(0).metadata.get(0)).isEqualTo(expectedSmtaEntry);
+    assertThat(trackGroups.get(0).getFormat(0).metadata.get(0))
-    assertThat(trackGroups.get(0).getFormat(0).metadata.get(1)).isEqualTo(expectedSlowMotionData);
+        .isEqualTo(expectedAndroidVersionMetadata);
-    assertThat(trackGroups.get(0).getFormat(0).metadata.get(2)).isEqualTo(expectedCreationTime);
+    assertThat(trackGroups.get(0).getFormat(0).metadata.get(1))
+        .isEqualTo(expectedTemporalLayersCountMetdata);
+    assertThat(trackGroups.get(0).getFormat(0).metadata.get(2)).isEqualTo(expectedSmtaEntry);
+    assertThat(trackGroups.get(0).getFormat(0).metadata.get(3)).isEqualTo(expectedSlowMotionData);
+    assertThat(trackGroups.get(0).getFormat(0).metadata.get(4)).isEqualTo(expectedCreationTime);
 
     // Video
-    assertThat(trackGroups.get(1).getFormat(0).metadata.length()).isEqualTo(4);
+    assertThat(trackGroups.get(1).getFormat(0).metadata.length()).isEqualTo(6);
-    assertThat(trackGroups.get(1).getFormat(0).metadata.get(0)).isEqualTo(expectedMdtaEntry);
+    assertThat(trackGroups.get(1).getFormat(0).metadata.get(0))
-    assertThat(trackGroups.get(1).getFormat(0).metadata.get(1)).isEqualTo(expectedSmtaEntry);
+        .isEqualTo(expectedAndroidVersionMetadata);
-    assertThat(trackGroups.get(1).getFormat(0).metadata.get(2)).isEqualTo(expectedSlowMotionData);
+    assertThat(trackGroups.get(1).getFormat(0).metadata.get(1))
-    assertThat(trackGroups.get(1).getFormat(0).metadata.get(3)).isEqualTo(expectedCreationTime);
+        .isEqualTo(expectedTemporalLayersCountMetdata);
+    assertThat(trackGroups.get(1).getFormat(0).metadata.get(2)).isEqualTo(expectedMdtaEntry);
+    assertThat(trackGroups.get(1).getFormat(0).metadata.get(3)).isEqualTo(expectedSmtaEntry);
+    assertThat(trackGroups.get(1).getFormat(0).metadata.get(4)).isEqualTo(expectedSlowMotionData);
+    assertThat(trackGroups.get(1).getFormat(0).metadata.get(5)).isEqualTo(expectedCreationTime);
   }
 
   @Test

libraries/extractor/src/main/java/androidx/media3/extractor/mp4/MetadataUtil.java

@@ -299,17 +299,20 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
       if (udtaMetaMetadata != null) {
         formatMetadata = udtaMetaMetadata;
       }
-    } else if (trackType == C.TRACK_TYPE_VIDEO) {
+    }
-      // Populate only metadata keys that are known to be specific to video.
+
     if (mdtaMetadata != null) {
       for (int i = 0; i < mdtaMetadata.length(); i++) {
         Metadata.Entry entry = mdtaMetadata.get(i);
         if (entry instanceof MdtaMetadataEntry) {
           MdtaMetadataEntry mdtaMetadataEntry = (MdtaMetadataEntry) entry;
-            if (MdtaMetadataEntry.KEY_ANDROID_CAPTURE_FPS.equals(mdtaMetadataEntry.key)) {
+          // This key is present in the container level meta box.
-              formatMetadata = new Metadata(mdtaMetadataEntry);
+          if (mdtaMetadataEntry.key.equals(MdtaMetadataEntry.KEY_ANDROID_CAPTURE_FPS)) {
-              break;
+            if (trackType == C.TRACK_TYPE_VIDEO) {
+              formatMetadata = formatMetadata.copyWithAppendedEntries(mdtaMetadataEntry);
             }
+          } else {
+            formatMetadata = formatMetadata.copyWithAppendedEntries(mdtaMetadataEntry);
           }
         }
       }

libraries/test_data/src/test/assets/extractordumps/mp4/sample_android_slow_motion.mp4.0.dump

@@ -22,7 +22,7 @@ track 0:
       colorRange = 1
       colorTransfer = -1
       hdrStaticInfo = length 0, hash 0
-    metadata = entries=[mdta: key=com.android.capture.fps, value=240.0, Creation time: unset]
+    metadata = entries=[mdta: key=major_brand, value=mp42, mdta: key=minor_version, value=0, mdta: key=compatible_brands, value=isommp42, mdta: key=com.android.capture.fps, value=240.0, mdta: key=com.android.version, value=10, mdta: key=encoder, value=Lavf58.29.100, Creation time: unset]
     initializationData:
       data = length 22, hash 4CF81805
       data = length 9, hash FBAFBA1C

libraries/test_data/src/test/assets/extractordumps/mp4/sample_android_slow_motion.mp4.1.dump

@@ -22,7 +22,7 @@ track 0:
       colorRange = 1
       colorTransfer = -1
       hdrStaticInfo = length 0, hash 0
-    metadata = entries=[mdta: key=com.android.capture.fps, value=240.0, Creation time: unset]
+    metadata = entries=[mdta: key=major_brand, value=mp42, mdta: key=minor_version, value=0, mdta: key=compatible_brands, value=isommp42, mdta: key=com.android.capture.fps, value=240.0, mdta: key=com.android.version, value=10, mdta: key=encoder, value=Lavf58.29.100, Creation time: unset]
     initializationData:
       data = length 22, hash 4CF81805
       data = length 9, hash FBAFBA1C

libraries/test_data/src/test/assets/extractordumps/mp4/sample_android_slow_motion.mp4.2.dump

@@ -22,7 +22,7 @@ track 0:
       colorRange = 1
       colorTransfer = -1
       hdrStaticInfo = length 0, hash 0
-    metadata = entries=[mdta: key=com.android.capture.fps, value=240.0, Creation time: unset]
+    metadata = entries=[mdta: key=major_brand, value=mp42, mdta: key=minor_version, value=0, mdta: key=compatible_brands, value=isommp42, mdta: key=com.android.capture.fps, value=240.0, mdta: key=com.android.version, value=10, mdta: key=encoder, value=Lavf58.29.100, Creation time: unset]
     initializationData:
       data = length 22, hash 4CF81805
       data = length 9, hash FBAFBA1C

libraries/test_data/src/test/assets/extractordumps/mp4/sample_android_slow_motion.mp4.3.dump

@@ -22,7 +22,7 @@ track 0:
       colorRange = 1
       colorTransfer = -1
       hdrStaticInfo = length 0, hash 0
-    metadata = entries=[mdta: key=com.android.capture.fps, value=240.0, Creation time: unset]
+    metadata = entries=[mdta: key=major_brand, value=mp42, mdta: key=minor_version, value=0, mdta: key=compatible_brands, value=isommp42, mdta: key=com.android.capture.fps, value=240.0, mdta: key=com.android.version, value=10, mdta: key=encoder, value=Lavf58.29.100, Creation time: unset]
     initializationData:
       data = length 22, hash 4CF81805
       data = length 9, hash FBAFBA1C

libraries/test_data/src/test/assets/extractordumps/mp4/sample_android_slow_motion.mp4.unknown_length.dump

@@ -22,7 +22,7 @@ track 0:
       colorRange = 1
       colorTransfer = -1
       hdrStaticInfo = length 0, hash 0
-    metadata = entries=[mdta: key=com.android.capture.fps, value=240.0, Creation time: unset]
+    metadata = entries=[mdta: key=major_brand, value=mp42, mdta: key=minor_version, value=0, mdta: key=compatible_brands, value=isommp42, mdta: key=com.android.capture.fps, value=240.0, mdta: key=com.android.version, value=10, mdta: key=encoder, value=Lavf58.29.100, Creation time: unset]
     initializationData:
       data = length 22, hash 4CF81805
       data = length 9, hash FBAFBA1C

libraries/test_data/src/test/assets/extractordumps/mp4/sample_with_color_info.mp4.0.dump

@@ -23,7 +23,7 @@ track 0:
       colorRange = 2
       colorTransfer = 7
       hdrStaticInfo = length 0, hash 0
-    metadata = entries=[Creation time: 1621959711000]
+    metadata = entries=[mdta: key=com.apple.quicktime.location.accuracy.horizontal, value=3.754789, mdta: key=com.apple.quicktime.location.ISO6709, value=+37.7450-122.4301+066.374/, mdta: key=com.apple.quicktime.make, value=Apple, mdta: key=com.apple.quicktime.model, value=iPhone 12 Pro Max, mdta: key=com.apple.quicktime.software, value=14.5.1, mdta: key=com.apple.quicktime.creationdate, value=2021-05-25T09:21:51-0700, Creation time: 1621959711000]
     initializationData:
       data = length 526, hash 7B3FC433
   sample 0:
@@ -75,7 +75,7 @@ track 1:
     sampleRate = 44100
     encoderPadding = 2204
     language = und
-    metadata = entries=[Creation time: 1621959711000]
+    metadata = entries=[mdta: key=com.apple.quicktime.location.accuracy.horizontal, value=3.754789, mdta: key=com.apple.quicktime.location.ISO6709, value=+37.7450-122.4301+066.374/, mdta: key=com.apple.quicktime.make, value=Apple, mdta: key=com.apple.quicktime.model, value=iPhone 12 Pro Max, mdta: key=com.apple.quicktime.software, value=14.5.1, mdta: key=com.apple.quicktime.creationdate, value=2021-05-25T09:21:51-0700, Creation time: 1621959711000]
     initializationData:
       data = length 2, hash 5FF
   sample 0:

libraries/test_data/src/test/assets/extractordumps/mp4/sample_with_color_info.mp4.1.dump

@@ -23,7 +23,7 @@ track 0:
       colorRange = 2
       colorTransfer = 7
       hdrStaticInfo = length 0, hash 0
-    metadata = entries=[Creation time: 1621959711000]
+    metadata = entries=[mdta: key=com.apple.quicktime.location.accuracy.horizontal, value=3.754789, mdta: key=com.apple.quicktime.location.ISO6709, value=+37.7450-122.4301+066.374/, mdta: key=com.apple.quicktime.make, value=Apple, mdta: key=com.apple.quicktime.model, value=iPhone 12 Pro Max, mdta: key=com.apple.quicktime.software, value=14.5.1, mdta: key=com.apple.quicktime.creationdate, value=2021-05-25T09:21:51-0700, Creation time: 1621959711000]
     initializationData:
       data = length 526, hash 7B3FC433
   sample 0:
@@ -75,7 +75,7 @@ track 1:
     sampleRate = 44100
     encoderPadding = 2204
     language = und
-    metadata = entries=[Creation time: 1621959711000]
+    metadata = entries=[mdta: key=com.apple.quicktime.location.accuracy.horizontal, value=3.754789, mdta: key=com.apple.quicktime.location.ISO6709, value=+37.7450-122.4301+066.374/, mdta: key=com.apple.quicktime.make, value=Apple, mdta: key=com.apple.quicktime.model, value=iPhone 12 Pro Max, mdta: key=com.apple.quicktime.software, value=14.5.1, mdta: key=com.apple.quicktime.creationdate, value=2021-05-25T09:21:51-0700, Creation time: 1621959711000]
     initializationData:
       data = length 2, hash 5FF
   sample 0:

libraries/test_data/src/test/assets/extractordumps/mp4/sample_with_color_info.mp4.2.dump

@@ -23,7 +23,7 @@ track 0:
       colorRange = 2
       colorTransfer = 7
       hdrStaticInfo = length 0, hash 0
-    metadata = entries=[Creation time: 1621959711000]
+    metadata = entries=[mdta: key=com.apple.quicktime.location.accuracy.horizontal, value=3.754789, mdta: key=com.apple.quicktime.location.ISO6709, value=+37.7450-122.4301+066.374/, mdta: key=com.apple.quicktime.make, value=Apple, mdta: key=com.apple.quicktime.model, value=iPhone 12 Pro Max, mdta: key=com.apple.quicktime.software, value=14.5.1, mdta: key=com.apple.quicktime.creationdate, value=2021-05-25T09:21:51-0700, Creation time: 1621959711000]
     initializationData:
       data = length 526, hash 7B3FC433
   sample 0:
@@ -75,7 +75,7 @@ track 1:
     sampleRate = 44100
     encoderPadding = 2204
     language = und
-    metadata = entries=[Creation time: 1621959711000]
+    metadata = entries=[mdta: key=com.apple.quicktime.location.accuracy.horizontal, value=3.754789, mdta: key=com.apple.quicktime.location.ISO6709, value=+37.7450-122.4301+066.374/, mdta: key=com.apple.quicktime.make, value=Apple, mdta: key=com.apple.quicktime.model, value=iPhone 12 Pro Max, mdta: key=com.apple.quicktime.software, value=14.5.1, mdta: key=com.apple.quicktime.creationdate, value=2021-05-25T09:21:51-0700, Creation time: 1621959711000]
     initializationData:
       data = length 2, hash 5FF
   sample 0:

libraries/test_data/src/test/assets/extractordumps/mp4/sample_with_color_info.mp4.3.dump

@@ -23,7 +23,7 @@ track 0:
       colorRange = 2
       colorTransfer = 7
       hdrStaticInfo = length 0, hash 0
-    metadata = entries=[Creation time: 1621959711000]
+    metadata = entries=[mdta: key=com.apple.quicktime.location.accuracy.horizontal, value=3.754789, mdta: key=com.apple.quicktime.location.ISO6709, value=+37.7450-122.4301+066.374/, mdta: key=com.apple.quicktime.make, value=Apple, mdta: key=com.apple.quicktime.model, value=iPhone 12 Pro Max, mdta: key=com.apple.quicktime.software, value=14.5.1, mdta: key=com.apple.quicktime.creationdate, value=2021-05-25T09:21:51-0700, Creation time: 1621959711000]
     initializationData:
       data = length 526, hash 7B3FC433
   sample 0:
@@ -75,7 +75,7 @@ track 1:
     sampleRate = 44100
     encoderPadding = 2204
     language = und
-    metadata = entries=[Creation time: 1621959711000]
+    metadata = entries=[mdta: key=com.apple.quicktime.location.accuracy.horizontal, value=3.754789, mdta: key=com.apple.quicktime.location.ISO6709, value=+37.7450-122.4301+066.374/, mdta: key=com.apple.quicktime.make, value=Apple, mdta: key=com.apple.quicktime.model, value=iPhone 12 Pro Max, mdta: key=com.apple.quicktime.software, value=14.5.1, mdta: key=com.apple.quicktime.creationdate, value=2021-05-25T09:21:51-0700, Creation time: 1621959711000]
     initializationData:
       data = length 2, hash 5FF
   sample 0:

libraries/test_data/src/test/assets/extractordumps/mp4/sample_with_color_info.mp4.unknown_length.dump

@@ -23,7 +23,7 @@ track 0:
       colorRange = 2
       colorTransfer = 7
       hdrStaticInfo = length 0, hash 0
-    metadata = entries=[Creation time: 1621959711000]
+    metadata = entries=[mdta: key=com.apple.quicktime.location.accuracy.horizontal, value=3.754789, mdta: key=com.apple.quicktime.location.ISO6709, value=+37.7450-122.4301+066.374/, mdta: key=com.apple.quicktime.make, value=Apple, mdta: key=com.apple.quicktime.model, value=iPhone 12 Pro Max, mdta: key=com.apple.quicktime.software, value=14.5.1, mdta: key=com.apple.quicktime.creationdate, value=2021-05-25T09:21:51-0700, Creation time: 1621959711000]
     initializationData:
       data = length 526, hash 7B3FC433
   sample 0:
@@ -75,7 +75,7 @@ track 1:
     sampleRate = 44100
     encoderPadding = 2204
     language = und
-    metadata = entries=[Creation time: 1621959711000]
+    metadata = entries=[mdta: key=com.apple.quicktime.location.accuracy.horizontal, value=3.754789, mdta: key=com.apple.quicktime.location.ISO6709, value=+37.7450-122.4301+066.374/, mdta: key=com.apple.quicktime.make, value=Apple, mdta: key=com.apple.quicktime.model, value=iPhone 12 Pro Max, mdta: key=com.apple.quicktime.software, value=14.5.1, mdta: key=com.apple.quicktime.creationdate, value=2021-05-25T09:21:51-0700, Creation time: 1621959711000]
     initializationData:
       data = length 2, hash 5FF
   sample 0:

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

@@ -0,0 +1,339 @@
+seekMap:
+  isSeekable = true
+  duration = 1065600
+  getPosition(0) = [[timeUs=0, position=44]]
+  getPosition(1) = [[timeUs=0, position=44]]
+  getPosition(532800) = [[timeUs=0, position=44]]
+  getPosition(1065600) = [[timeUs=0, position=44]]
+numberOfTracks = 2
+track 0:
+  total output bytes = 89876
+  sample count = 30
+  format 0:
+    id = 1
+    sampleMimeType = video/avc
+    codecs = avc1.64001F
+    maxInputSize = 36722
+    width = 1080
+    height = 720
+    frameRate = 32.113037
+    metadata = entries=[mdta: key=StringKey, value=StringValue, mdta: key=FloatKey, value=600.0, xyz: latitude=40.68, longitude=-74.5, Creation time: 1464714095000]
+    initializationData:
+      data = length 29, hash 4746B5D9
+      data = length 10, hash 7A0D0F2B
+  sample 0:
+    time = 0
+    flags = 1
+    data = length 36692, hash D216076E
+  sample 1:
+    time = 66722
+    flags = 0
+    data = length 5312, hash D45D3CA0
+  sample 2:
+    time = 33355
+    flags = 0
+    data = length 599, hash 1BE7812D
+  sample 3:
+    time = 200200
+    flags = 0
+    data = length 7735, hash 4490F110
+  sample 4:
+    time = 133455
+    flags = 0
+    data = length 987, hash 560B5036
+  sample 5:
+    time = 100100
+    flags = 0
+    data = length 673, hash ED7CD8C7
+  sample 6:
+    time = 166822
+    flags = 0
+    data = length 523, hash 3020DF50
+  sample 7:
+    time = 333655
+    flags = 0
+    data = length 6061, hash 736C72B2
+  sample 8:
+    time = 266922
+    flags = 0
+    data = length 992, hash FE132F23
+  sample 9:
+    time = 233555
+    flags = 0
+    data = length 623, hash 5B2C1816
+  sample 10:
+    time = 300300
+    flags = 0
+    data = length 421, hash 742E69C1
+  sample 11:
+    time = 433755
+    flags = 0
+    data = length 4899, hash F72F86A1
+  sample 12:
+    time = 400400
+    flags = 0
+    data = length 568, hash 519A8E50
+  sample 13:
+    time = 367022
+    flags = 0
+    data = length 620, hash 3990AA39
+  sample 14:
+    time = 567222
+    flags = 0
+    data = length 5450, hash F06EC4AA
+  sample 15:
+    time = 500500
+    flags = 0
+    data = length 1051, hash 92DFA63A
+  sample 16:
+    time = 467122
+    flags = 0
+    data = length 874, hash 69587FB4
+  sample 17:
+    time = 533855
+    flags = 0
+    data = length 781, hash 36BE495B
+  sample 18:
+    time = 700700
+    flags = 0
+    data = length 4725, hash AC0C8CD3
+  sample 19:
+    time = 633955
+    flags = 0
+    data = length 1022, hash 5D8BFF34
+  sample 20:
+    time = 600600
+    flags = 0
+    data = length 790, hash 99413A99
+  sample 21:
+    time = 667322
+    flags = 0
+    data = length 610, hash 5E129290
+  sample 22:
+    time = 834155
+    flags = 0
+    data = length 2751, hash 769974CB
+  sample 23:
+    time = 767422
+    flags = 0
+    data = length 745, hash B78A477A
+  sample 24:
+    time = 734055
+    flags = 0
+    data = length 621, hash CF741E7A
+  sample 25:
+    time = 800800
+    flags = 0
+    data = length 505, hash 1DB4894E
+  sample 26:
+    time = 967622
+    flags = 0
+    data = length 1268, hash C15348DC
+  sample 27:
+    time = 900900
+    flags = 0
+    data = length 880, hash C2DE85D0
+  sample 28:
+    time = 867522
+    flags = 0
+    data = length 530, hash C98BC6A8
+  sample 29:
+    time = 934255
+    flags = 536870912
+    data = length 568, hash 4FE5C8EA
+track 1:
+  total output bytes = 9529
+  sample count = 45
+  format 0:
+    peakBitrate = 200000
+    id = 2
+    sampleMimeType = audio/mp4a-latm
+    codecs = mp4a.40.2
+    maxInputSize = 294
+    channelCount = 1
+    sampleRate = 44100
+    language = und
+    metadata = entries=[mdta: key=StringKey, value=StringValue, mdta: key=FloatKey, value=600.0, xyz: latitude=40.68, longitude=-74.5, Creation time: 1464714095000]
+    initializationData:
+      data = length 2, hash 5F7
+  sample 0:
+    time = 0
+    flags = 1
+    data = length 23, hash 47DE9131
+  sample 1:
+    time = 67208
+    flags = 1
+    data = length 6, hash 31EC5206
+  sample 2:
+    time = 90437
+    flags = 1
+    data = length 148, hash 894A176B
+  sample 3:
+    time = 113645
+    flags = 1
+    data = length 189, hash CEF235A1
+  sample 4:
+    time = 136875
+    flags = 1
+    data = length 205, hash BBF5F7B0
+  sample 5:
+    time = 160083
+    flags = 1
+    data = length 210, hash F278B193
+  sample 6:
+    time = 183312
+    flags = 1
+    data = length 210, hash 82DA1589
+  sample 7:
+    time = 206520
+    flags = 1
+    data = length 207, hash 5BE231DF
+  sample 8:
+    time = 229750
+    flags = 1
+    data = length 225, hash 18819EE1
+  sample 9:
+    time = 252958
+    flags = 1
+    data = length 215, hash CA7FA67B
+  sample 10:
+    time = 276187
+    flags = 1
+    data = length 211, hash 581A1C18
+  sample 11:
+    time = 299416
+    flags = 1
+    data = length 216, hash ADB88187
+  sample 12:
+    time = 322625
+    flags = 1
+    data = length 229, hash 2E8BA4DC
+  sample 13:
+    time = 345854
+    flags = 1
+    data = length 232, hash 22F0C510
+  sample 14:
+    time = 369062
+    flags = 1
+    data = length 235, hash 867AD0DC
+  sample 15:
+    time = 392291
+    flags = 1
+    data = length 231, hash 84E823A8
+  sample 16:
+    time = 415500
+    flags = 1
+    data = length 226, hash 1BEF3A95
+  sample 17:
+    time = 438729
+    flags = 1
+    data = length 216, hash EAA345AE
+  sample 18:
+    time = 461958
+    flags = 1
+    data = length 229, hash 6957411F
+  sample 19:
+    time = 485166
+    flags = 1
+    data = length 219, hash 41275022
+  sample 20:
+    time = 508395
+    flags = 1
+    data = length 241, hash 6495DF96
+  sample 21:
+    time = 531604
+    flags = 1
+    data = length 228, hash 63D95906
+  sample 22:
+    time = 554833
+    flags = 1
+    data = length 238, hash 34F676F9
+  sample 23:
+    time = 578041
+    flags = 1
+    data = length 234, hash E5CBC045
+  sample 24:
+    time = 601270
+    flags = 1
+    data = length 231, hash 5FC43661
+  sample 25:
+    time = 624479
+    flags = 1
+    data = length 217, hash 682708ED
+  sample 26:
+    time = 647708
+    flags = 1
+    data = length 239, hash D43780FC
+  sample 27:
+    time = 670937
+    flags = 1
+    data = length 243, hash C5E17980
+  sample 28:
+    time = 694145
+    flags = 1
+    data = length 231, hash AC5837BA
+  sample 29:
+    time = 717375
+    flags = 1
+    data = length 230, hash 169EE895
+  sample 30:
+    time = 740583
+    flags = 1
+    data = length 238, hash C48FF3F1
+  sample 31:
+    time = 763812
+    flags = 1
+    data = length 225, hash 531E4599
+  sample 32:
+    time = 787020
+    flags = 1
+    data = length 232, hash CB3C6B8D
+  sample 33:
+    time = 810250
+    flags = 1
+    data = length 243, hash F8C94C7
+  sample 34:
+    time = 833458
+    flags = 1
+    data = length 232, hash A646A7D0
+  sample 35:
+    time = 856687
+    flags = 1
+    data = length 237, hash E8B787A5
+  sample 36:
+    time = 879916
+    flags = 1
+    data = length 228, hash 3FA7A29F
+  sample 37:
+    time = 903125
+    flags = 1
+    data = length 235, hash B9B33B0A
+  sample 38:
+    time = 926354
+    flags = 1
+    data = length 264, hash 71A4869E
+  sample 39:
+    time = 949562
+    flags = 1
+    data = length 257, hash D049B54C
+  sample 40:
+    time = 972791
+    flags = 1
+    data = length 227, hash 66757231
+  sample 41:
+    time = 996000
+    flags = 1
+    data = length 227, hash BD374F1B
+  sample 42:
+    time = 1019229
+    flags = 1
+    data = length 235, hash 999477F6
+  sample 43:
+    time = 1042437
+    flags = 1
+    data = length 229, hash FFF98DF0
+  sample 44:
+    time = 1065666
+    flags = 536870913
+    data = length 6, hash 31B22286
+tracksEnded = true

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

@@ -6,19 +6,19 @@ format 0:
   width = 320
   height = 240
   frameRate = 29.523811
-  metadata = entries=[mdta: key=com.android.capture.fps, value=240.0, smta: captureFrameRate=240.0, svcTemporalLayerCount=4, SlowMotion: segments=[Segment: startTimeMs=88, endTimeMs=879, speedDivisor=2, Segment: startTimeMs=1255, endTimeMs=1970, speedDivisor=8], Creation time: 1604060090000]
+  metadata = entries=[mdta: key=com.android.version, value=10, mdta: key=com.android.video.temporal_layers_count, value=4, mdta: key=com.android.capture.fps, value=240.0, smta: captureFrameRate=240.0, svcTemporalLayerCount=4, SlowMotion: segments=[Segment: startTimeMs=88, endTimeMs=879, speedDivisor=2, Segment: startTimeMs=1255, endTimeMs=1970, speedDivisor=8], Creation time: 1604060090000]
   initializationData:
     data = length 33, hash D3FB879D
     data = length 10, hash 7A0D0F2B
-container metadata = entries=[mdta: key=com.android.capture.fps, value=240.0, smta: captureFrameRate=240.0, svcTemporalLayerCount=4, SlowMotion: segments=[Segment: startTimeMs=88, endTimeMs=879, speedDivisor=2, Segment: startTimeMs=1255, endTimeMs=1970, speedDivisor=8], Creation time: 1604060090000]
+container metadata = entries=[mdta: key=com.android.version, value=10, mdta: key=com.android.video.temporal_layers_count, value=4, mdta: key=com.android.capture.fps, value=240.0, smta: captureFrameRate=240.0, svcTemporalLayerCount=4, SlowMotion: segments=[Segment: startTimeMs=88, endTimeMs=879, speedDivisor=2, Segment: startTimeMs=1255, endTimeMs=1970, speedDivisor=8], Creation time: 1604060090000]
 format 1:
   averageBitrate = 131072
   sampleMimeType = audio/mp4a-latm
   channelCount = 2
   sampleRate = 12000
   pcmEncoding = 2
-  metadata = entries=[smta: captureFrameRate=240.0, svcTemporalLayerCount=4, SlowMotion: segments=[Segment: startTimeMs=88, endTimeMs=879, speedDivisor=2, Segment: startTimeMs=1255, endTimeMs=1970, speedDivisor=8], Creation time: 1604060090000]
+  metadata = entries=[mdta: key=com.android.version, value=10, mdta: key=com.android.video.temporal_layers_count, value=4, smta: captureFrameRate=240.0, svcTemporalLayerCount=4, SlowMotion: segments=[Segment: startTimeMs=88, endTimeMs=879, speedDivisor=2, Segment: startTimeMs=1255, endTimeMs=1970, speedDivisor=8], Creation time: 1604060090000]
-container metadata = entries=[smta: captureFrameRate=240.0, svcTemporalLayerCount=4, SlowMotion: segments=[Segment: startTimeMs=88, endTimeMs=879, speedDivisor=2, Segment: startTimeMs=1255, endTimeMs=1970, speedDivisor=8], Creation time: 1604060090000]
+container metadata = entries=[mdta: key=com.android.version, value=10, mdta: key=com.android.video.temporal_layers_count, value=4, smta: captureFrameRate=240.0, svcTemporalLayerCount=4, SlowMotion: segments=[Segment: startTimeMs=88, endTimeMs=879, speedDivisor=2, Segment: startTimeMs=1255, endTimeMs=1970, speedDivisor=8], Creation time: 1604060090000]
 sample:
   trackIndex = 1
   dataHashCode = -212376212

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

@@ -24,6 +24,7 @@ import androidx.media3.common.Format;
 import androidx.media3.common.Metadata;
 import androidx.media3.common.MimeTypes;
 import androidx.media3.common.util.UnstableApi;
+import androidx.media3.common.util.Util;
 import androidx.media3.container.CreationTime;
 import androidx.media3.container.MdtaMetadataEntry;
 import androidx.media3.container.Mp4LocationData;
@@ -186,8 +187,11 @@ public final class InAppMuxer implements Muxer {
           || entry instanceof XmpData
           || entry instanceof CreationTime
           || (entry instanceof MdtaMetadataEntry
-              && ((MdtaMetadataEntry) entry)
+              && (((MdtaMetadataEntry) entry).key.equals(MdtaMetadataEntry.KEY_ANDROID_CAPTURE_FPS)
-                  .key.equals(MdtaMetadataEntry.KEY_ANDROID_CAPTURE_FPS))) {
+                  || ((MdtaMetadataEntry) entry).typeIndicator
+                      == MdtaMetadataEntry.TYPE_INDICATOR_STRING
+                  || ((MdtaMetadataEntry) entry).typeIndicator
+                      == MdtaMetadataEntry.TYPE_INDICATOR_FLOAT32))) {
         metadataEntries.add(entry);
       }
     }
@@ -232,6 +236,10 @@ public final class InAppMuxer implements Muxer {
         if (mdtaMetadataEntry.key.equals(MdtaMetadataEntry.KEY_ANDROID_CAPTURE_FPS)) {
           byte[] captureFps = mdtaMetadataEntry.value;
           mp4Muxer.setCaptureFps(ByteBuffer.wrap(captureFps).getFloat());
+        } else if (mdtaMetadataEntry.typeIndicator == MdtaMetadataEntry.TYPE_INDICATOR_STRING) {
+          mp4Muxer.addMetadata(mdtaMetadataEntry.key, Util.fromUtf8Bytes(mdtaMetadataEntry.value));
+        } else if (mdtaMetadataEntry.typeIndicator == MdtaMetadataEntry.TYPE_INDICATOR_FLOAT32) {
+          mp4Muxer.addMetadata(mdtaMetadataEntry.key, Util.toFloat(mdtaMetadataEntry.value));
         } else {
           throw new IllegalStateException("Unsupported MdtaMetadataEntry " + mdtaMetadataEntry.key);
         }

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

@@ -116,13 +116,13 @@ public class TransformerWithInAppMuxerEndToEndTest {
         new InAppMuxer.Factory(
             DefaultMuxer.Factory.DEFAULT_MAX_DELAY_BETWEEN_SAMPLES_MS,
             metadataEntries -> {
-              byte[] captureFps = new byte[] {66, 112, 0, 0}; // 60.0f
+              float captureFps = 60.0f;
               metadataEntries.add(
                   new MdtaMetadataEntry(
                       MdtaMetadataEntry.KEY_ANDROID_CAPTURE_FPS,
-                      /* value= */ captureFps,
+                      /* value= */ Util.toByteArray(captureFps),
                       /* localeIndicator= */ 0,
-                      MdtaMetadataEntry.TYPE_INDICATOR_FLOAT));
+                      MdtaMetadataEntry.TYPE_INDICATOR_FLOAT32));
             });
     Transformer transformer =
         new Transformer.Builder(context)
@@ -166,4 +166,46 @@ public class TransformerWithInAppMuxerEndToEndTest {
     DumpFileAsserts.assertOutput(
         context, fakeExtractorOutput, TestUtil.getDumpFileName(H264_MP4 + ".with_creation_time"));
   }
+
+  @Test
+  public void transmux_withCustomeMetadata_outputMatchesExpected() throws Exception {
+    Muxer.Factory inAppMuxerFactory =
+        new InAppMuxer.Factory(
+            DefaultMuxer.Factory.DEFAULT_MAX_DELAY_BETWEEN_SAMPLES_MS,
+            metadataEntries -> {
+              String stringKey = "StringKey";
+              String stringValue = "StringValue";
+              metadataEntries.add(
+                  new MdtaMetadataEntry(
+                      stringKey,
+                      Util.getUtf8Bytes(stringValue),
+                      /* localeIndicator= */ 0,
+                      MdtaMetadataEntry.TYPE_INDICATOR_STRING));
+              String floatKey = "FloatKey";
+              float floatValue = 600.0f;
+              metadataEntries.add(
+                  new MdtaMetadataEntry(
+                      floatKey,
+                      Util.toByteArray(floatValue),
+                      /* localeIndicator= */ 0,
+                      MdtaMetadataEntry.TYPE_INDICATOR_FLOAT32));
+            });
+    Transformer transformer =
+        new Transformer.Builder(context)
+            .setClock(new FakeClock(/* isAutoAdvancing= */ true))
+            .setMuxerFactory(inAppMuxerFactory)
+            .build();
+    MediaItem mediaItem = MediaItem.fromUri(Uri.parse(MP4_FILE_ASSET_DIRECTORY + H264_MP4));
+
+    transformer.start(mediaItem, outputPath);
+    TransformerTestRunner.runLooper(transformer);
+
+    FakeExtractorOutput fakeExtractorOutput =
+        androidx.media3.test.utils.TestUtil.extractAllSamplesFromFilePath(
+            new Mp4Extractor(), checkNotNull(outputPath));
+    // [mdta: key=StringKey, value=StringValue, mdta: key=FloatKey, value=600.0] in track metadata
+    // dump
+    DumpFileAsserts.assertOutput(
+        context, fakeExtractorOutput, TestUtil.getDumpFileName(H264_MP4 + ".with_custom_metadata"));
+  }
 }