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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.media;
     18 
     19 import android.annotation.NonNull;
     20 import android.media.MediaCryptoException;
     21 import java.util.UUID;
     22 
     23 /**
     24  * MediaCrypto class can be used in conjunction with {@link android.media.MediaCodec}
     25  * to decode encrypted media data.
     26  *
     27  * Crypto schemes are assigned 16 byte UUIDs,
     28  * the method {@link #isCryptoSchemeSupported} can be used to query if a given
     29  * scheme is supported on the device.
     30  *
     31  */
     32 public final class MediaCrypto {
     33     /**
     34      * Query if the given scheme identified by its UUID is supported on
     35      * this device.
     36      * @param uuid The UUID of the crypto scheme.
     37      */
     38     public static final boolean isCryptoSchemeSupported(@NonNull UUID uuid) {
     39         return isCryptoSchemeSupportedNative(getByteArrayFromUUID(uuid));
     40     }
     41 
     42     @NonNull
     43     private static final byte[] getByteArrayFromUUID(@NonNull UUID uuid) {
     44         long msb = uuid.getMostSignificantBits();
     45         long lsb = uuid.getLeastSignificantBits();
     46 
     47         byte[] uuidBytes = new byte[16];
     48         for (int i = 0; i < 8; ++i) {
     49             uuidBytes[i] = (byte)(msb >>> (8 * (7 - i)));
     50             uuidBytes[8 + i] = (byte)(lsb >>> (8 * (7 - i)));
     51         }
     52 
     53         return uuidBytes;
     54     }
     55 
     56     private static final native boolean isCryptoSchemeSupportedNative(@NonNull byte[] uuid);
     57 
     58     /**
     59      * Instantiate a MediaCrypto object using opaque, crypto scheme specific
     60      * data.
     61      * @param uuid The UUID of the crypto scheme.
     62      * @param initData Opaque initialization data specific to the crypto scheme.
     63      */
     64     public MediaCrypto(@NonNull UUID uuid, @NonNull byte[] initData) throws MediaCryptoException {
     65         native_setup(getByteArrayFromUUID(uuid), initData);
     66     }
     67 
     68     /**
     69      * Query if the crypto scheme requires the use of a secure decoder
     70      * to decode data of the given mime type.
     71      * @param mime The mime type of the media data
     72      */
     73     public final native boolean requiresSecureDecoderComponent(@NonNull String mime);
     74 
     75     /**
     76      * Associate a MediaDrm session with this MediaCrypto instance.  The
     77      * MediaDrm session is used to securely load decryption keys for a
     78      * crypto scheme.  The crypto keys loaded through the MediaDrm session
     79      * may be selected for use during the decryption operation performed
     80      * by {@link android.media.MediaCodec#queueSecureInputBuffer} by specifying
     81      * their key ids in the {@link android.media.MediaCodec.CryptoInfo#key} field.
     82      * @param sessionId the MediaDrm sessionId to associate with this
     83      * MediaCrypto instance
     84      * @throws MediaCryptoException on failure to set the sessionId
     85      */
     86     public final native void setMediaDrmSession(@NonNull byte[] sessionId)
     87         throws MediaCryptoException;
     88 
     89     @Override
     90     protected void finalize() {
     91         native_finalize();
     92     }
     93 
     94     public native final void release();
     95     private static native final void native_init();
     96 
     97     private native final void native_setup(@NonNull byte[] uuid, @NonNull byte[] initData)
     98         throws MediaCryptoException;
     99 
    100     private native final void native_finalize();
    101 
    102     static {
    103         System.loadLibrary("media_jni");
    104         native_init();
    105     }
    106 
    107     private long mNativeContext;
    108 }
    109