1 files changed, 103 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/TrackEncryptionBox.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/TrackEncryptionBox.java
new file mode 100644
index 0000000000..04bfb82210
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/TrackEncryptionBox.java
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.mp4;
+
+import androidx.annotation.Nullable;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.TrackOutput;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Log;
+
+/**
+ * Encapsulates information parsed from a track encryption (tenc) box or sample group description
+ * (sgpd) box in an MP4 stream.
+ */
+public final class TrackEncryptionBox {
+
+  private static final String TAG = "TrackEncryptionBox";
+
+  /**
+   * Indicates the encryption state of the samples in the sample group.
+   */
+  public final boolean isEncrypted;
+
+  /**
+   * The protection scheme type, as defined by the 'schm' box, or null if unknown.
+   */
+  @Nullable public final String schemeType;
+
+  /**
+   * A {@link TrackOutput.CryptoData} instance containing the encryption information from this
+   * {@link TrackEncryptionBox}.
+   */
+  public final TrackOutput.CryptoData cryptoData;
+
+  /** The initialization vector size in bytes for the samples in the corresponding sample group. */
+  public final int perSampleIvSize;
+
+  /**
+   * If {@link #perSampleIvSize} is 0, holds the default initialization vector as defined in the
+   * track encryption box or sample group description box. Null otherwise.
+   */
+  @Nullable public final byte[] defaultInitializationVector;
+
+  /**
+   * @param isEncrypted See {@link #isEncrypted}.
+   * @param schemeType See {@link #schemeType}.
+   * @param perSampleIvSize See {@link #perSampleIvSize}.
+   * @param keyId See {@link TrackOutput.CryptoData#encryptionKey}.
+   * @param defaultEncryptedBlocks See {@link TrackOutput.CryptoData#encryptedBlocks}.
+   * @param defaultClearBlocks See {@link TrackOutput.CryptoData#clearBlocks}.
+   * @param defaultInitializationVector See {@link #defaultInitializationVector}.
+   */
+  public TrackEncryptionBox(
+      boolean isEncrypted,
+      @Nullable String schemeType,
+      int perSampleIvSize,
+      byte[] keyId,
+      int defaultEncryptedBlocks,
+      int defaultClearBlocks,
+      @Nullable byte[] defaultInitializationVector) {
+    Assertions.checkArgument(perSampleIvSize == 0 ^ defaultInitializationVector == null);
+    this.isEncrypted = isEncrypted;
+    this.schemeType = schemeType;
+    this.perSampleIvSize = perSampleIvSize;
+    this.defaultInitializationVector = defaultInitializationVector;
+    cryptoData = new TrackOutput.CryptoData(schemeToCryptoMode(schemeType), keyId,
+        defaultEncryptedBlocks, defaultClearBlocks);
+  }
+
+  @C.CryptoMode
+  private static int schemeToCryptoMode(@Nullable String schemeType) {
+    if (schemeType == null) {
+      // If unknown, assume cenc.
+      return C.CRYPTO_MODE_AES_CTR;
+    }
+    switch (schemeType) {
+      case C.CENC_TYPE_cenc:
+      case C.CENC_TYPE_cens:
+        return C.CRYPTO_MODE_AES_CTR;
+      case C.CENC_TYPE_cbc1:
+      case C.CENC_TYPE_cbcs:
+        return C.CRYPTO_MODE_AES_CBC;
+      default:
+        Log.w(TAG, "Unsupported protection scheme type '" + schemeType + "'. Assuming AES-CTR "
+            + "crypto mode.");
+        return C.CRYPTO_MODE_AES_CTR;
+    }
+  }
+
+}