Fix byte order for HDR10+ static metadata

The implementation of writing HDR10+ static metadata assumed that the
application would use default (big endian) byte order for this metadata but
MediaCodec expects the order to match the specification CTA-861.3.

PiperOrigin-RevId: 281050806

RELEASENOTES.md

@@ -10,6 +10,7 @@
   [embedded in Matroska streams](https://matroska.org/technical/specs/subtitles/index.html).
 * Use `ExoMediaDrm.Provider` in `OfflineLicenseHelper` to avoid `ExoMediaDrm`
   leaks ([#4721](https://github.com/google/ExoPlayer/issues/4721)).
+* Fix byte order of HDR10+ static metadata to match CTA-861.3.
 
 ### 2.11.0 (not yet released) ###
 

library/core/src/main/java/com/google/android/exoplayer2/extractor/mkv/MatroskaExtractor.java

@@ -1912,9 +1912,9 @@ public class MatroskaExtractor implements Extractor {
           initializationData = new ArrayList<>(3);
           initializationData.add(codecPrivate);
           initializationData.add(
-              ByteBuffer.allocate(8).order(ByteOrder.nativeOrder()).putLong(codecDelayNs).array());
+              ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN).putLong(codecDelayNs).array());
           initializationData.add(
-              ByteBuffer.allocate(8).order(ByteOrder.nativeOrder()).putLong(seekPreRollNs).array());
+              ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN).putLong(seekPreRollNs).array());
           break;
         case CODEC_ID_AAC:
           mimeType = MimeTypes.AUDIO_AAC;
@@ -2116,6 +2116,7 @@ public class MatroskaExtractor implements Extractor {
     }
 
     /** Returns the HDR Static Info as defined in CTA-861.3. */
+    @Nullable
     private byte[] getHdrStaticInfo() {
       // Are all fields present.
       if (primaryRChromaticityX == Format.NO_VALUE || primaryRChromaticityY == Format.NO_VALUE
@@ -2128,7 +2129,7 @@ public class MatroskaExtractor implements Extractor {
       }
 
       byte[] hdrStaticInfoData = new byte[25];
-      ByteBuffer hdrStaticInfo = ByteBuffer.wrap(hdrStaticInfoData);
+      ByteBuffer hdrStaticInfo = ByteBuffer.wrap(hdrStaticInfoData).order(ByteOrder.LITTLE_ENDIAN);
       hdrStaticInfo.put((byte) 0);  // Type.
       hdrStaticInfo.putShort((short) ((primaryRChromaticityX * MAX_CHROMATICITY) + 0.5f));
       hdrStaticInfo.putShort((short) ((primaryRChromaticityY * MAX_CHROMATICITY) + 0.5f));