Update Pssh Atom Util to expose internal data class, parse v1 PSSH atoms

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

@@ -72,10 +72,11 @@ public final class PsshAtomUtil {
     if (data != null && data.length != 0) {
       psshBox.putInt(data.length);
       psshBox.put(data);
-    } // Else the last 4 bytes are a 0 DataSize.
+    } else {
+      psshBox.putInt(0);
+    }
     return psshBox.array();
   }
-
   /**
    * Returns whether the data is a valid PSSH atom.
    *
@@ -152,23 +153,29 @@ public final class PsshAtomUtil {
    * @return The parsed PSSH atom. Null if the input is not a valid PSSH atom, or if the PSSH atom
    *     has an unsupported version.
    */
-  // TODO: Support parsing of the key ids for version 1 PSSH atoms.
   @Nullable
-  private static PsshAtom parsePsshAtom(byte[] atom) {
+  public static PsshAtom parsePsshAtom(byte[] atom) {
     ParsableByteArray atomData = new ParsableByteArray(atom);
     if (atomData.limit() < Atom.FULL_HEADER_SIZE + 16 /* UUID */ + 4 /* DataSize */) {
       // Data too short.
       return null;
     }
     atomData.setPosition(0);
+    int bufferLength = atomData.bytesLeft();
     int atomSize = atomData.readInt();
-    if (atomSize != atomData.bytesLeft() + 4) {
+
-      // Not an atom, or incorrect atom size.
+    if (atomSize != bufferLength) {
+      Log.w(
+          TAG,
+          "Advertised atom size ("
+              + atomSize
+              + ") does not match current buffer size: "
+              + bufferLength);
       return null;
     }
     int atomType = atomData.readInt();
     if (atomType != Atom.TYPE_pssh) {
-      // Not an atom, or incorrect atom type.
+      Log.w(TAG, "Atom Type is not pssh: " + atomType);
       return null;
     }
     int atomVersion = Atom.parseFullAtomVersion(atomData.readInt());
@@ -177,31 +184,47 @@ public final class PsshAtomUtil {
       return null;
     }
     UUID uuid = new UUID(atomData.readLong(), atomData.readLong());
+    UUID[] keyIds = null;
+    int dataSize = 0;
     if (atomVersion == 1) {
       int keyIdCount = atomData.readUnsignedIntToInt();
-      atomData.skipBytes(16 * keyIdCount);
+      keyIds = new UUID[keyIdCount];
+      for (int i = 0; i < keyIdCount; ++i) {
+        keyIds[i] = new UUID(atomData.readLong(), atomData.readLong());
       }
-    int dataSize = atomData.readUnsignedIntToInt();
+    } else if (atomVersion == 0) {
-    if (dataSize != atomData.bytesLeft()) {
+      dataSize = atomData.readUnsignedIntToInt();
-      // Incorrect dataSize.
+      bufferLength = atomData.bytesLeft();
+      if (dataSize != bufferLength) {
+        Log.w(
+            TAG,
+            "Atom data size (" + dataSize + ") does not match the bytes left: " + bufferLength);
         return null;
       }
+    }
     byte[] data = new byte[dataSize];
     atomData.readBytes(data, 0, dataSize);
-    return new PsshAtom(uuid, atomVersion, data);
+    return new PsshAtom(uuid, atomVersion, data, keyIds);
   }
 
-  // TODO: Consider exposing this and making parsePsshAtom public.
+  /**
-  private static class PsshAtom {
+   * A class representing the mp4 PSSH Atom as specified in the CENC standard - systemId the UUID of
+   * the encryption system as specified in ISO/IEC 23009-1 section 5.8.4.1 - version the version of
+   * the PSSH atom, should be 0 or 1 - schemaData the binary data in the atom - keyIds the optional
+   * set of keyIds associated with the
+   */
+  public static class PsshAtom {
 
-    private final UUID uuid;
+    public final UUID uuid;
-    private final int version;
+    public final int version;
-    private final byte[] schemeData;
+    public final byte[] schemeData;
+    @Nullable public final UUID[] keyIds;
 
-    public PsshAtom(UUID uuid, int version, byte[] schemeData) {
+    public PsshAtom(UUID uuid, int version, byte[] schemeData, @Nullable UUID[] keyIds) {
       this.uuid = uuid;
       this.version = version;
       this.schemeData = schemeData;
+      this.keyIds = keyIds;
     }
   }
 }

libraries/extractor/src/test/java/androidx/media3/extractor/mp4/PsshAtomUtilTest.java

@@ -50,4 +50,53 @@ public final class PsshAtomUtilTest {
     parsablePsshAtom.readBytes(psshSchemeData, 0, schemeData.length);
     assertThat(psshSchemeData).isEqualTo(schemeData);
   }
+
+  @Test
+  public void buildVersion1Pssh() {
+    byte[] schemeData = new byte[] {0, 1, 2, 3, 4, 5};
+    UUID[] keyIds = new UUID[2];
+    keyIds[0] = UUID.fromString("edef8ba9-79d6-4ace-a3c8-27dcd51d21ed");
+    keyIds[1] = UUID.fromString("dc03d7f3-334d-b858-f114-9ab759a925fb");
+    byte[] psshAtom = PsshAtomUtil.buildPsshAtom(C.WIDEVINE_UUID, keyIds, schemeData);
+    ParsableByteArray parsablePsshAtom = new ParsableByteArray(psshAtom);
+    assertThat(parsablePsshAtom.readUnsignedIntToInt()).isEqualTo(psshAtom.length);
+    assertThat(parsablePsshAtom.readInt()).isEqualTo(TYPE_pssh); // type
+    int fullAtomInt = parsablePsshAtom.readInt(); // version + flags
+    assertThat(parseFullAtomVersion(fullAtomInt)).isEqualTo(1);
+    assertThat(parseFullAtomFlags(fullAtomInt)).isEqualTo(0);
+    UUID systemId = new UUID(parsablePsshAtom.readLong(), parsablePsshAtom.readLong());
+    assertThat(systemId).isEqualTo(WIDEVINE_UUID);
+    assertThat(parsablePsshAtom.readUnsignedIntToInt()).isEqualTo(2);
+    UUID keyId0 = new UUID(parsablePsshAtom.readLong(), parsablePsshAtom.readLong());
+    assertThat(keyId0).isEqualTo(keyIds[0]);
+    UUID keyId1 = new UUID(parsablePsshAtom.readLong(), parsablePsshAtom.readLong());
+    assertThat(keyId1).isEqualTo(keyIds[1]);
+    assertThat(parsablePsshAtom.readUnsignedIntToInt()).isEqualTo(schemeData.length);
+    byte[] psshSchemeData = new byte[schemeData.length];
+    parsablePsshAtom.readBytes(psshSchemeData, 0, schemeData.length);
+    assertThat(psshSchemeData).isEqualTo(schemeData);
+  }
+
+  @Test
+  public void parseV1Atom() {
+    byte[] psshBuffer = {
+        0x00, 0x00, 0x00, 0x44, 0x70, 0x73, 0x73, 0x68, // BMFF box header (68 bytes, 'pssh')
+        0x01, 0x00, 0x00, 0x00, // Full box header (version = 1, flags = 0)
+        0x10, 0x77, -0x11, -0x14, -0x40, -0x4e, 0x4d, 0x02, // SystemID
+        -0x54, -0x1d, 0x3c, 0x1e, 0x52, -0x1e, -0x05, 0x4b, 0x00, 0x00, 0x00, 0x02, // KID_count (2)
+        0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, // First KID ("0123456789012345")
+        0x38, 0x39, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
+        0x48, // Second KID ("ABCDEFGHIJKLMNOP")
+        0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x00, 0x00, 0x00, 0x00, // Size of Data (0)
+    };
+    PsshAtomUtil.PsshAtom psshAtom = PsshAtomUtil.parsePsshAtom(psshBuffer);
+    assertThat(psshAtom).isNotNull();
+    System.out.println("psshAtom: " + psshAtom);
+    assertThat(psshAtom.version).isEqualTo(1);
+    assertThat(psshAtom.uuid)
+        .isEqualTo(UUID.fromString("1077efec-c0b2-4d02-ace3-3c1e52e2fb4b"));
+    assertThat(psshAtom.keyIds).isNotNull();
+    assertThat(psshAtom.keyIds.length).isEqualTo(2);
+    assertThat(psshAtom.schemeData).isEmpty();
+  }
 }