Allow replacement of libraries for Opus/Flac/Ffmpeg too

- Also make some of the naming more concise + misc style cleanup.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=132899979

extensions/ffmpeg/src/main/java/com/google/android/exoplayer2/ext/ffmpeg/FfmpegAudioRenderer.java

@@ -62,11 +62,11 @@ public final class FfmpegAudioRenderer extends SimpleDecoderAudioRenderer {
 
   @Override
   public int supportsFormat(Format format) {
-    if (!FfmpegDecoder.IS_AVAILABLE) {
+    if (!FfmpegLibrary.isAvailable()) {
       return FORMAT_UNSUPPORTED_TYPE;
     }
     String mimeType = format.sampleMimeType;
-    return FfmpegDecoder.supportsFormat(mimeType) ? FORMAT_HANDLED
+    return FfmpegLibrary.supportsFormat(mimeType) ? FORMAT_HANDLED
         : MimeTypes.isAudio(mimeType) ? FORMAT_UNSUPPORTED_SUBTYPE : FORMAT_UNSUPPORTED_TYPE;
   }
 

extensions/ffmpeg/src/main/java/com/google/android/exoplayer2/ext/ffmpeg/FfmpegDecoder.java

@@ -23,39 +23,11 @@ import java.nio.ByteBuffer;
 import java.util.List;
 
 /**
- * JNI wrapper for FFmpeg. Only audio decoding is supported.
+ * FFmpeg audio decoder.
  */
 /* package */ final class FfmpegDecoder extends
     SimpleDecoder<DecoderInputBuffer, SimpleOutputBuffer, FfmpegDecoderException> {
 
-  private static final String TAG = "FfmpegDecoder";
-
-  /**
-   * Whether the underlying FFmpeg library is available.
-   */
-  public static final boolean IS_AVAILABLE;
-  static {
-    boolean isAvailable;
-    try {
-      System.loadLibrary("avutil");
-      System.loadLibrary("avresample");
-      System.loadLibrary("avcodec");
-      System.loadLibrary("ffmpeg");
-      isAvailable = true;
-    } catch (UnsatisfiedLinkError exception) {
-      isAvailable = false;
-    }
-    IS_AVAILABLE = isAvailable;
-  }
-
-  /**
-   * Returns whether this decoder can decode samples in the specified MIME type.
-   */
-  public static boolean supportsFormat(String mimeType) {
-    String codecName = getCodecName(mimeType);
-    return codecName != null && nativeHasDecoder(codecName);
-  }
-
   // Space for 64 ms of 6 channel 48 kHz 16-bit PCM audio.
   private static final int OUTPUT_BUFFER_SIZE = 1536 * 6 * 2 * 2;
 
@@ -70,9 +42,12 @@ import java.util.List;
   public FfmpegDecoder(int numInputBuffers, int numOutputBuffers, int initialInputBufferSize,
       String mimeType, List<byte[]> initializationData) throws FfmpegDecoderException {
     super(new DecoderInputBuffer[numInputBuffers], new SimpleOutputBuffer[numOutputBuffers]);
-    codecName = getCodecName(mimeType);
+    if (!FfmpegLibrary.isAvailable()) {
+      throw new FfmpegDecoderException("Failed to load decoder native libraries.");
+    }
+    codecName = FfmpegLibrary.getCodecName(mimeType);
     extraData = getExtraData(mimeType, initializationData);
-    nativeContext = nativeInitialize(codecName, extraData);
+    nativeContext = ffmpegInitialize(codecName, extraData);
     if (nativeContext == 0) {
       throw new FfmpegDecoderException("Initialization failed.");
     }
@@ -81,7 +56,7 @@ import java.util.List;
 
   @Override
   public String getName() {
-    return "ffmpeg" + nativeGetFfmpegVersion() + "-" + codecName;
+    return "ffmpeg" + FfmpegLibrary.getVersion() + "-" + codecName;
   }
 
   @Override
@@ -98,7 +73,7 @@ import java.util.List;
   public FfmpegDecoderException decode(DecoderInputBuffer inputBuffer,
       SimpleOutputBuffer outputBuffer, boolean reset) {
     if (reset) {
-      nativeContext = nativeReset(nativeContext, extraData);
+      nativeContext = ffmpegReset(nativeContext, extraData);
       if (nativeContext == 0) {
         return new FfmpegDecoderException("Error resetting (see logcat).");
       }
@@ -106,13 +81,13 @@ import java.util.List;
     ByteBuffer inputData = inputBuffer.data;
     int inputSize = inputData.limit();
     ByteBuffer outputData = outputBuffer.init(inputBuffer.timeUs, OUTPUT_BUFFER_SIZE);
-    int result = nativeDecode(nativeContext, inputData, inputSize, outputData, OUTPUT_BUFFER_SIZE);
+    int result = ffmpegDecode(nativeContext, inputData, inputSize, outputData, OUTPUT_BUFFER_SIZE);
     if (result < 0) {
       return new FfmpegDecoderException("Error decoding (see logcat). Code: " + result);
     }
     if (!hasOutputFormat) {
-      channelCount = nativeGetChannelCount(nativeContext);
-      sampleRate = nativeGetSampleRate(nativeContext);
+      channelCount = ffmpegGetChannelCount(nativeContext);
+      sampleRate = ffmpegGetSampleRate(nativeContext);
       hasOutputFormat = true;
     }
     outputBuffer.data.position(0);
@@ -123,7 +98,7 @@ import java.util.List;
   @Override
   public void release() {
     super.release();
-    nativeRelease(nativeContext);
+    ffmpegRelease(nativeContext);
     nativeContext = 0;
   }
 
@@ -169,50 +144,12 @@ import java.util.List;
     }
   }
 
-  /**
-   * Returns the name of the FFmpeg decoder that could be used to decode {@code mimeType}. The codec
-   * can only be used if {@link #nativeHasDecoder(String)} returns true for the returned codec name.
-   */
-  private static String getCodecName(String mimeType) {
-    switch (mimeType) {
-      case MimeTypes.AUDIO_AAC:
-        return "aac";
-      case MimeTypes.AUDIO_MPEG:
-      case MimeTypes.AUDIO_MPEG_L1:
-      case MimeTypes.AUDIO_MPEG_L2:
-        return "mp3";
-      case MimeTypes.AUDIO_AC3:
-        return "ac3";
-      case MimeTypes.AUDIO_E_AC3:
-        return "eac3";
-      case MimeTypes.AUDIO_TRUEHD:
-        return "truehd";
-      case MimeTypes.AUDIO_DTS:
-      case MimeTypes.AUDIO_DTS_HD:
-        return "dca";
-      case MimeTypes.AUDIO_VORBIS:
-        return "vorbis";
-      case MimeTypes.AUDIO_OPUS:
-        return "opus";
-      case MimeTypes.AUDIO_AMR_NB:
-        return "amrnb";
-      case MimeTypes.AUDIO_AMR_WB:
-        return "amrwb";
-      case MimeTypes.AUDIO_FLAC:
-        return "flac";
-      default:
-        return null;
-    }
-  }
-
-  private static native String nativeGetFfmpegVersion();
-  private static native boolean nativeHasDecoder(String codecName);
-  private native long nativeInitialize(String codecName, byte[] extraData);
-  private native int nativeDecode(long context, ByteBuffer inputData, int inputSize,
+  private native long ffmpegInitialize(String codecName, byte[] extraData);
+  private native int ffmpegDecode(long context, ByteBuffer inputData, int inputSize,
       ByteBuffer outputData, int outputSize);
-  private native int nativeGetChannelCount(long context);
-  private native int nativeGetSampleRate(long context);
-  private native long nativeReset(long context, byte[] extraData);
-  private native void nativeRelease(long context);
+  private native int ffmpegGetChannelCount(long context);
+  private native int ffmpegGetSampleRate(long context);
+  private native long ffmpegReset(long context, byte[] extraData);
+  private native void ffmpegRelease(long context);
 
 }

extensions/ffmpeg/src/main/java/com/google/android/exoplayer2/ext/ffmpeg/FfmpegLibrary.java

+/*
+ * 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 com.google.android.exoplayer2.ext.ffmpeg;
+
+import com.google.android.exoplayer2.util.LibraryLoader;
+import com.google.android.exoplayer2.util.MimeTypes;
+
+/**
+ * Configures and queries the underlying native library.
+ */
+public final class FfmpegLibrary {
+
+  private static final LibraryLoader LOADER =
+      new LibraryLoader("avutil", "avresample", "avcodec", "ffmpeg");
+
+  private FfmpegLibrary() {}
+
+  /**
+   * Override the names of the FFmpeg native libraries. If an application wishes to call this
+   * method, it must do so before calling any other method defined by this class, and before
+   * instantiating a {@link FfmpegAudioRenderer} instance.
+   */
+  public static void setLibraries(String... libraries) {
+    LOADER.setLibraries(libraries);
+  }
+
+  /**
+   * Returns whether the underlying library is available, loading it if necessary.
+   */
+  public static boolean isAvailable() {
+    return LOADER.isAvailable();
+  }
+
+  /**
+   * Returns the version of the underlying library if available, or null otherwise.
+   */
+  public static String getVersion() {
+    return isAvailable() ? ffmpegGetVersion() : null;
+  }
+
+  /**
+   * Returns whether the underlying library supports the specified MIME type.
+   */
+  public static boolean supportsFormat(String mimeType) {
+    if (!isAvailable()) {
+      return false;
+    }
+    String codecName = getCodecName(mimeType);
+    return codecName != null && ffmpegHasDecoder(codecName);
+  }
+
+  /**
+   * Returns the name of the FFmpeg decoder that could be used to decode {@code mimeType}.
+   */
+  /* package */ static String getCodecName(String mimeType) {
+    switch (mimeType) {
+      case MimeTypes.AUDIO_AAC:
+        return "aac";
+      case MimeTypes.AUDIO_MPEG:
+      case MimeTypes.AUDIO_MPEG_L1:
+      case MimeTypes.AUDIO_MPEG_L2:
+        return "mp3";
+      case MimeTypes.AUDIO_AC3:
+        return "ac3";
+      case MimeTypes.AUDIO_E_AC3:
+        return "eac3";
+      case MimeTypes.AUDIO_TRUEHD:
+        return "truehd";
+      case MimeTypes.AUDIO_DTS:
+      case MimeTypes.AUDIO_DTS_HD:
+        return "dca";
+      case MimeTypes.AUDIO_VORBIS:
+        return "vorbis";
+      case MimeTypes.AUDIO_OPUS:
+        return "opus";
+      case MimeTypes.AUDIO_AMR_NB:
+        return "amrnb";
+      case MimeTypes.AUDIO_AMR_WB:
+        return "amrwb";
+      case MimeTypes.AUDIO_FLAC:
+        return "flac";
+      default:
+        return null;
+    }
+  }
+
+  private static native String ffmpegGetVersion();
+  private static native boolean ffmpegHasDecoder(String codecName);
+
+}

extensions/ffmpeg/src/main/jni/ffmpeg_jni.cc

@@ -34,7 +34,8 @@ extern "C" {
 #define LOG_TAG "ffmpeg_jni"
 #define LOGE(...) ((void)__android_log_print(ANDROID_LOG_ERROR, LOG_TAG, \
                    __VA_ARGS__))
-#define FUNC(RETURN_TYPE, NAME, ...) \
+
+#define DECODER_FUNC(RETURN_TYPE, NAME, ...) \
   extern "C" { \
   JNIEXPORT RETURN_TYPE \
     Java_com_google_android_exoplayer2_ext_ffmpeg_FfmpegDecoder_ ## NAME \
@@ -44,6 +45,16 @@ extern "C" {
     Java_com_google_android_exoplayer2_ext_ffmpeg_FfmpegDecoder_ ## NAME \
       (JNIEnv* env, jobject thiz, ##__VA_ARGS__)\
 
+#define LIBRARY_FUNC(RETURN_TYPE, NAME, ...) \
+  extern "C" { \
+  JNIEXPORT RETURN_TYPE \
+    Java_com_google_android_exoplayer2_ext_ffmpeg_FfmpegLibrary_ ## NAME \
+      (JNIEnv* env, jobject thiz, ##__VA_ARGS__);\
+  } \
+  JNIEXPORT RETURN_TYPE \
+    Java_com_google_android_exoplayer2_ext_ffmpeg_FfmpegLibrary_ ## NAME \
+      (JNIEnv* env, jobject thiz, ##__VA_ARGS__)\
+
 #define ERROR_STRING_BUFFER_LENGTH 256
 
 // Request a format corresponding to AudioFormat.ENCODING_PCM_16BIT.
@@ -88,15 +99,15 @@ jint JNI_OnLoad(JavaVM *vm, void *reserved) {
   return JNI_VERSION_1_6;
 }
 
-FUNC(jstring, nativeGetFfmpegVersion) {
+LIBRARY_FUNC(jstring, ffmpegGetVersion) {
   return env->NewStringUTF(LIBAVCODEC_IDENT);
 }
 
-FUNC(jboolean, nativeHasDecoder, jstring codecName) {
+LIBRARY_FUNC(jboolean, ffmpegHasDecoder, jstring codecName) {
   return getCodecByName(env, codecName) != NULL;
 }
 
-FUNC(jlong, nativeInitialize, jstring codecName, jbyteArray extraData) {
+DECODER_FUNC(jlong, ffmpegInitialize, jstring codecName, jbyteArray extraData) {
   AVCodec *codec = getCodecByName(env, codecName);
   if (!codec) {
     LOGE("Codec not found.");
@@ -105,8 +116,8 @@ FUNC(jlong, nativeInitialize, jstring codecName, jbyteArray extraData) {
   return (jlong) createContext(env, codec, extraData);
 }
 
-FUNC(jint, nativeDecode, jlong context, jobject inputData, jint inputSize,
-     jobject outputData, jint outputSize) {
+DECODER_FUNC(jint, ffmpegDecode, jlong context, jobject inputData,
+    jint inputSize, jobject outputData, jint outputSize) {
   if (!context) {
     LOGE("Context must be non-NULL.");
     return -1;
@@ -133,7 +144,7 @@ FUNC(jint, nativeDecode, jlong context, jobject inputData, jint inputSize,
                       outputSize);
 }
 
-FUNC(jint, nativeGetChannelCount, jlong context) {
+DECODER_FUNC(jint, ffmpegGetChannelCount, jlong context) {
   if (!context) {
     LOGE("Context must be non-NULL.");
     return -1;
@@ -141,7 +152,7 @@ FUNC(jint, nativeGetChannelCount, jlong context) {
   return ((AVCodecContext *) context)->channels;
 }
 
-FUNC(jint, nativeGetSampleRate, jlong context) {
+DECODER_FUNC(jint, ffmpegGetSampleRate, jlong context) {
   if (!context) {
     LOGE("Context must be non-NULL.");
     return -1;
@@ -149,7 +160,7 @@ FUNC(jint, nativeGetSampleRate, jlong context) {
   return ((AVCodecContext *) context)->sample_rate;
 }
 
-FUNC(jlong, nativeReset, jlong jContext, jbyteArray extraData) {
+DECODER_FUNC(jlong, ffmpegReset, jlong jContext, jbyteArray extraData) {
   AVCodecContext *context = (AVCodecContext *) jContext;
   if (!context) {
     LOGE("Tried to reset without a context.");
@@ -173,7 +184,7 @@ FUNC(jlong, nativeReset, jlong jContext, jbyteArray extraData) {
   return (jlong) context;
 }
 
-FUNC(void, nativeRelease, jlong context) {
+DECODER_FUNC(void, ffmpegRelease, jlong context) {
   if (context) {
     releaseContext((AVCodecContext *) context);
   }

extensions/flac/src/main/java/com/google/android/exoplayer2/ext/flac/FlacDecoder.java

@@ -45,13 +45,10 @@ import java.util.List;
       throws FlacDecoderException {
     super(new DecoderInputBuffer[numInputBuffers], new SimpleOutputBuffer[numOutputBuffers]);
     if (initializationData.size() != 1) {
-      throw new FlacDecoderException("Wrong number of initialization data");
+      throw new FlacDecoderException("Initialization data must be of length 1");
     }
-
     decoder = new FlacJni();
-
-    ByteBuffer metadata = ByteBuffer.wrap(initializationData.get(0));
-    decoder.setData(metadata);
+    decoder.setData(ByteBuffer.wrap(initializationData.get(0)));
     FlacStreamInfo streamInfo;
     try {
       streamInfo = decoder.decodeMetadata();

extensions/flac/src/main/java/com/google/android/exoplayer2/ext/flac/FlacExtractor.java

@@ -69,7 +69,6 @@ public final class FlacExtractor implements Extractor {
     extractorOutput = output;
     trackOutput = extractorOutput.track(0);
     extractorOutput.endTracks();
-
     try {
       decoder = new FlacJni();
     } catch (FlacDecoderException e) {

extensions/flac/src/main/java/com/google/android/exoplayer2/ext/flac/FlacJni.java

@@ -26,32 +26,19 @@ import java.nio.ByteBuffer;
  */
 /* package */ final class FlacJni {
 
-  /**
-   * Whether the underlying libflac library is available.
-   */
-  public static final boolean IS_AVAILABLE;
-  static {
-    boolean isAvailable;
-    try {
-      System.loadLibrary("flacJNI");
-      isAvailable = true;
-    } catch (UnsatisfiedLinkError exception) {
-      isAvailable = false;
-    }
-    IS_AVAILABLE = isAvailable;
-  }
-
   private static final int TEMP_BUFFER_SIZE = 8192; // The same buffer size which libflac has
 
   private final long nativeDecoderContext;
 
   private ByteBuffer byteBufferData;
-
   private ExtractorInput extractorInput;
   private boolean endOfExtractorInput;
   private byte[] tempBuffer;
 
   public FlacJni() throws FlacDecoderException {
+    if (!FlacLibrary.isAvailable()) {
+      throw new FlacDecoderException("Failed to load decoder native libraries.");
+    }
     nativeDecoderContext = flacInit();
     if (nativeDecoderContext == 0) {
       throw new FlacDecoderException("Failed to initialize decoder");
@@ -194,28 +181,18 @@ import java.nio.ByteBuffer;
   }
 
   private native long flacInit();
-
   private native FlacStreamInfo flacDecodeMetadata(long context)
       throws IOException, InterruptedException;
-
   private native int flacDecodeToBuffer(long context, ByteBuffer outputBuffer)
       throws IOException, InterruptedException;
-
   private native int flacDecodeToArray(long context, byte[] outputArray)
       throws IOException, InterruptedException;
-
   private native long flacGetDecodePosition(long context);
-
   private native long flacGetLastTimestamp(long context);
-
   private native long flacGetSeekPosition(long context, long timeUs);
-
   private native String flacGetStateString(long context);
-
   private native void flacFlush(long context);
-
   private native void flacReset(long context, long newPosition);
-
   private native void flacRelease(long context);
 
 }

extensions/flac/src/main/java/com/google/android/exoplayer2/ext/flac/FlacLibrary.java

+/*
+ * 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 com.google.android.exoplayer2.ext.flac;
+
+import com.google.android.exoplayer2.util.LibraryLoader;
+
+/**
+ * Configures and queries the underlying native library.
+ */
+public final class FlacLibrary {
+
+  private static final LibraryLoader LOADER = new LibraryLoader("flacJNI");
+
+  private FlacLibrary() {}
+
+  /**
+   * Override the names of the Flac native libraries. If an application wishes to call this method,
+   * it must do so before calling any other method defined by this class, and before instantiating
+   * any {@link LibflacAudioRenderer} and {@link FlacExtractor} instances.
+   */
+  public static void setLibraries(String... libraries) {
+    LOADER.setLibraries(libraries);
+  }
+
+  /**
+   * Returns whether the underlying library is available, loading it if necessary.
+   */
+  public static boolean isAvailable() {
+    return LOADER.isAvailable();
+  }
+
+}

extensions/flac/src/main/java/com/google/android/exoplayer2/ext/flac/LibflacAudioRenderer.java

@@ -30,13 +30,6 @@ public class LibflacAudioRenderer extends SimpleDecoderAudioRenderer {
 
   private static final int NUM_BUFFERS = 16;
 
-  /**
-   * Returns whether the underlying libflac library is available.
-   */
-  public static boolean isLibflacAvailable() {
-    return FlacJni.IS_AVAILABLE;
-  }
-
   public LibflacAudioRenderer() {
     this(null, null);
   }
@@ -65,7 +58,7 @@ public class LibflacAudioRenderer extends SimpleDecoderAudioRenderer {
 
   @Override
   public int supportsFormat(Format format) {
-    return isLibflacAvailable() && MimeTypes.AUDIO_FLAC.equalsIgnoreCase(format.sampleMimeType)
+    return FlacLibrary.isAvailable() && MimeTypes.AUDIO_FLAC.equalsIgnoreCase(format.sampleMimeType)
         ? FORMAT_HANDLED : FORMAT_UNSUPPORTED_TYPE;
   }
 

extensions/flac/src/main/jni/flac_jni.cc

@@ -22,7 +22,7 @@
 
 #include "include/flac_parser.h"
 
-#define LOG_TAG "FlacJniJNI"
+#define LOG_TAG "flac_jni"
 #define ALOGE(...) \
   ((void)__android_log_print(ANDROID_LOG_ERROR, LOG_TAG, __VA_ARGS__))
 #define ALOGV(...) \

extensions/opus/src/main/java/com/google/android/exoplayer2/ext/opus/LibopusAudioRenderer.java

@@ -31,20 +31,6 @@ public final class LibopusAudioRenderer extends SimpleDecoderAudioRenderer {
   private static final int NUM_BUFFERS = 16;
   private static final int INITIAL_INPUT_BUFFER_SIZE = 960 * 6;
 
-  /**
-   * Returns whether the underlying libopus library is available.
-   */
-  public static boolean isLibopusAvailable() {
-    return OpusDecoder.IS_AVAILABLE;
-  }
-
-  /**
-   * Returns the version of the underlying libopus library if available, otherwise {@code null}.
-   */
-  public static String getLibopusVersion() {
-    return isLibopusAvailable() ? OpusDecoder.getLibopusVersion() : null;
-  }
-
   public LibopusAudioRenderer() {
     this(null, null);
   }
@@ -73,7 +59,7 @@ public final class LibopusAudioRenderer extends SimpleDecoderAudioRenderer {
 
   @Override
   public int supportsFormat(Format format) {
-    return isLibopusAvailable() && MimeTypes.AUDIO_OPUS.equalsIgnoreCase(format.sampleMimeType)
+    return OpusLibrary.isAvailable() && MimeTypes.AUDIO_OPUS.equalsIgnoreCase(format.sampleMimeType)
         ? FORMAT_HANDLED : FORMAT_UNSUPPORTED_TYPE;
   }
 

extensions/opus/src/main/java/com/google/android/exoplayer2/ext/opus/OpusDecoder.java

@@ -24,32 +24,11 @@ import java.nio.ByteOrder;
 import java.util.List;
 
 /**
- * JNI wrapper for the libopus Opus decoder.
+ * Opus decoder.
  */
 /* package */ final class OpusDecoder extends
     SimpleDecoder<DecoderInputBuffer, SimpleOutputBuffer, OpusDecoderException> {
 
-  /**
-   * Whether the underlying libopus library is available.
-   */
-  public static final boolean IS_AVAILABLE;
-  static {
-    boolean isAvailable;
-    try {
-      System.loadLibrary("opus");
-      System.loadLibrary("opusJNI");
-      isAvailable = true;
-    } catch (UnsatisfiedLinkError exception) {
-      isAvailable = false;
-    }
-    IS_AVAILABLE = isAvailable;
-  }
-
-  /**
-   * Returns the version string of the underlying libopus decoder.
-   */
-  public static native String getLibopusVersion();
-
   private static final int DEFAULT_SEEK_PRE_ROLL_SAMPLES = 3840;
 
   /**
@@ -78,6 +57,9 @@ import java.util.List;
   public OpusDecoder(int numInputBuffers, int numOutputBuffers, int initialInputBufferSize,
       List<byte[]> initializationData) throws OpusDecoderException {
     super(new DecoderInputBuffer[numInputBuffers], new SimpleOutputBuffer[numOutputBuffers]);
+    if (!OpusLibrary.isAvailable()) {
+      throw new OpusDecoderException("Failed to load decoder native libraries.");
+    }
     byte[] headerBytes = initializationData.get(0);
     if (headerBytes.length < 19) {
       throw new OpusDecoderException("Header size is too small.");
@@ -90,7 +72,8 @@ import java.util.List;
     int gain = readLittleEndian16(headerBytes, 16);
 
     byte[] streamMap = new byte[8];
-    int numStreams, numCoupled;
+    int numStreams;
+    int numCoupled;
     if (headerBytes[18] == 0) { // Channel mapping
       // If there is no channel mapping, use the defaults.
       if (channelCount > 2) { // Maximum channel count with default layout.
@@ -133,7 +116,7 @@ import java.util.List;
 
   @Override
   public String getName() {
-    return "libopus" + getLibopusVersion();
+    return "libopus" + OpusLibrary.getVersion();
   }
 
   @Override
@@ -185,14 +168,6 @@ import java.util.List;
     opusClose(nativeDecoderContext);
   }
 
-  private native long opusInit(int sampleRate, int channelCount, int numStreams, int numCoupled,
-      int gain, byte[] streamMap);
-  private native int opusDecode(long decoder, long timeUs, ByteBuffer inputBuffer, int inputSize,
-      SimpleOutputBuffer outputBuffer, int sampleRate);
-  private native void opusClose(long decoder);
-  private native void opusReset(long decoder);
-  private native String opusGetErrorMessage(int errorCode);
-
   private static int nsToSamples(long ns) {
     return (int) (ns * SAMPLE_RATE / 1000000000);
   }
@@ -203,4 +178,12 @@ import java.util.List;
     return value;
   }
 
+  private native long opusInit(int sampleRate, int channelCount, int numStreams, int numCoupled,
+      int gain, byte[] streamMap);
+  private native int opusDecode(long decoder, long timeUs, ByteBuffer inputBuffer, int inputSize,
+      SimpleOutputBuffer outputBuffer, int sampleRate);
+  private native void opusClose(long decoder);
+  private native void opusReset(long decoder);
+  private native String opusGetErrorMessage(int errorCode);
+
 }

extensions/opus/src/main/java/com/google/android/exoplayer2/ext/opus/OpusLibrary.java

+/*
+ * 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 com.google.android.exoplayer2.ext.opus;
+
+import com.google.android.exoplayer2.util.LibraryLoader;
+
+/**
+ * Configures and queries the underlying native library.
+ */
+public final class OpusLibrary {
+
+  private static final LibraryLoader LOADER = new LibraryLoader("opus", "opusJNI");
+
+  private OpusLibrary() {}
+
+  /**
+   * Override the names of the Opus native libraries. If an application wishes to call this method,
+   * it must do so before calling any other method defined by this class, and before instantiating a
+   * {@link LibopusAudioRenderer} instance.
+   */
+  public static void setLibraries(String... libraries) {
+    LOADER.setLibraries(libraries);
+  }
+
+  /**
+   * Returns whether the underlying library is available, loading it if necessary.
+   */
+  public static boolean isAvailable() {
+    return LOADER.isAvailable();
+  }
+
+  /**
+   * Returns the version of the underlying library if available, or null otherwise.
+   */
+  public static String getVersion() {
+    return isAvailable() ? opusGetVersion() : null;
+  }
+
+  public static native String opusGetVersion();
+
+}

extensions/opus/src/main/jni/opus_jni.cc

@@ -23,11 +23,11 @@
 #include "opus.h"  // NOLINT
 #include "opus_multistream.h"  // NOLINT
 
-#define LOG_TAG "libopus_native"
+#define LOG_TAG "opus_jni"
 #define LOGE(...) ((void)__android_log_print(ANDROID_LOG_ERROR, LOG_TAG, \
                                              __VA_ARGS__))
 
-#define FUNC(RETURN_TYPE, NAME, ...) \
+#define DECODER_FUNC(RETURN_TYPE, NAME, ...) \
   extern "C" { \
   JNIEXPORT RETURN_TYPE \
     Java_com_google_android_exoplayer2_ext_opus_OpusDecoder_ ## NAME \
@@ -37,6 +37,16 @@
     Java_com_google_android_exoplayer2_ext_opus_OpusDecoder_ ## NAME \
       (JNIEnv* env, jobject thiz, ##__VA_ARGS__)\
 
+#define LIBRARY_FUNC(RETURN_TYPE, NAME, ...) \
+  extern "C" { \
+  JNIEXPORT RETURN_TYPE \
+    Java_com_google_android_exoplayer2_ext_opus_OpusLibrary_ ## NAME \
+      (JNIEnv* env, jobject thiz, ##__VA_ARGS__);\
+  } \
+  JNIEXPORT RETURN_TYPE \
+    Java_com_google_android_exoplayer2_ext_opus_OpusLibrary_ ## NAME \
+      (JNIEnv* env, jobject thiz, ##__VA_ARGS__)\
+
 // JNI references for SimpleOutputBuffer class.
 static jmethodID outputBufferInit;
 
@@ -51,8 +61,8 @@ jint JNI_OnLoad(JavaVM* vm, void* reserved) {
 static const int kBytesPerSample = 2;  // opus fixed point uses 16 bit samples.
 static int channelCount;
 
-FUNC(jlong, opusInit, jint sampleRate, jint channelCount, jint numStreams,
-     jint numCoupled, jint gain, jbyteArray jStreamMap) {
+DECODER_FUNC(jlong, opusInit, jint sampleRate, jint channelCount,
+     jint numStreams, jint numCoupled, jint gain, jbyteArray jStreamMap) {
   int status = OPUS_INVALID_STATE;
   ::channelCount = channelCount;
   jbyte* streamMapBytes = env->GetByteArrayElements(jStreamMap, 0);
@@ -79,8 +89,9 @@ FUNC(jlong, opusInit, jint sampleRate, jint channelCount, jint numStreams,
   return reinterpret_cast<intptr_t>(decoder);
 }
 
-FUNC(jint, opusDecode, jlong jDecoder, jlong jTimeUs, jobject jInputBuffer,
-     jint inputSize, jobject jOutputBuffer, jint sampleRate) {
+DECODER_FUNC(jint, opusDecode, jlong jDecoder, jlong jTimeUs,
+     jobject jInputBuffer, jint inputSize, jobject jOutputBuffer,
+     jint sampleRate) {
   OpusMSDecoder* decoder = reinterpret_cast<OpusMSDecoder*>(jDecoder);
   const uint8_t* inputBuffer =
       reinterpret_cast<const uint8_t*>(
@@ -102,20 +113,20 @@ FUNC(jint, opusDecode, jlong jDecoder, jlong jTimeUs, jobject jInputBuffer,
       : sampleCount * kBytesPerSample * channelCount;
 }
 
-FUNC(void, opusClose, jlong jDecoder) {
+DECODER_FUNC(void, opusClose, jlong jDecoder) {
   OpusMSDecoder* decoder = reinterpret_cast<OpusMSDecoder*>(jDecoder);
   opus_multistream_decoder_destroy(decoder);
 }
 
-FUNC(void, opusReset, jlong jDecoder) {
+DECODER_FUNC(void, opusReset, jlong jDecoder) {
   OpusMSDecoder* decoder = reinterpret_cast<OpusMSDecoder*>(jDecoder);
   opus_multistream_decoder_ctl(decoder, OPUS_RESET_STATE);
 }
 
-FUNC(jstring, getLibopusVersion) {
-  return env->NewStringUTF(opus_get_version_string());
+DECODER_FUNC(jstring, opusGetErrorMessage, jint errorCode) {
+  return env->NewStringUTF(opus_strerror(errorCode));
 }
 
-FUNC(jstring, opusGetErrorMessage, jint errorCode) {
-  return env->NewStringUTF(opus_strerror(errorCode));
+LIBRARY_FUNC(jstring, opusGetVersion) {
+  return env->NewStringUTF(opus_get_version_string());
 }

extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/LibvpxVideoRenderer.java

@@ -118,8 +118,7 @@ public final class LibvpxVideoRenderer extends BaseRenderer {
 
   @Override
   public int supportsFormat(Format format) {
-    return VpxNativeLibraryHelper.isLibvpxAvailable()
-        && MimeTypes.VIDEO_VP9.equalsIgnoreCase(format.sampleMimeType)
+    return VpxLibrary.isAvailable() && MimeTypes.VIDEO_VP9.equalsIgnoreCase(format.sampleMimeType)
         ? (FORMAT_HANDLED | ADAPTIVE_SEAMLESS) : FORMAT_UNSUPPORTED_TYPE;
   }
 

extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxDecoder.java

@@ -21,7 +21,7 @@ import com.google.android.exoplayer2.decoder.SimpleDecoder;
 import java.nio.ByteBuffer;
 
 /**
- * JNI wrapper for the libvpx VP9 decoder.
+ * Vpx decoder.
  */
 /* package */ final class VpxDecoder extends
     SimpleDecoder<DecoderInputBuffer, VpxOutputBuffer, VpxDecoderException> {
@@ -45,7 +45,7 @@ import java.nio.ByteBuffer;
   public VpxDecoder(int numInputBuffers, int numOutputBuffers, int initialInputBufferSize)
       throws VpxDecoderException {
     super(new DecoderInputBuffer[numInputBuffers], new VpxOutputBuffer[numOutputBuffers]);
-    if (!VpxNativeLibraryHelper.isLibvpxAvailable()) {
+    if (!VpxLibrary.isAvailable()) {
       throw new VpxDecoderException("Failed to load decoder native libraries.");
     }
     vpxDecContext = vpxInit();
@@ -57,7 +57,7 @@ import java.nio.ByteBuffer;
 
   @Override
   public String getName() {
-    return "libvpx" + VpxNativeLibraryHelper.getLibvpxVersion();
+    return "libvpx" + VpxLibrary.getVersion();
   }
 
   /**
@@ -111,4 +111,5 @@ import java.nio.ByteBuffer;
   private native long vpxDecode(long context, ByteBuffer encoded, int length);
   private native int vpxGetFrame(long context, VpxOutputBuffer outputBuffer);
   private native String vpxGetErrorMessage(long context);
+
 }

extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxLibrary.java

+/*
+ * 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 com.google.android.exoplayer2.ext.vp9;
+
+import com.google.android.exoplayer2.util.LibraryLoader;
+
+/**
+ * Configures and queries the underlying native library.
+ */
+public final class VpxLibrary {
+
+  private static final LibraryLoader LOADER = new LibraryLoader("vpx", "vpxJNI");
+
+  private VpxLibrary() {}
+
+  /**
+   * Override the names of the Vpx native libraries. If an application wishes to call this method,
+   * it must do so before calling any other method defined by this class, and before instantiating a
+   * {@link LibvpxVideoRenderer} instance.
+   */
+  public static void setLibraries(String... libraries) {
+    LOADER.setLibraries(libraries);
+  }
+
+  /**
+   * Returns whether the underlying library is available, loading it if necessary.
+   */
+  public static boolean isAvailable() {
+    return LOADER.isAvailable();
+  }
+
+  /**
+   * Returns the version of the underlying library if available, or null otherwise.
+   */
+  public static String getVersion() {
+    return isAvailable() ? vpxGetVersion() : null;
+  }
+
+  /**
+   * Returns the configuration string with which the underlying library was built if available, or
+   * null otherwise.
+   */
+  public static String getBuildConfig() {
+    return isAvailable() ? vpxGetBuildConfig() : null;
+  }
+
+  private static native String vpxGetVersion();
+  private static native String vpxGetBuildConfig();
+
+}

extensions/vp9/src/main/jni/vpx_jni.cc

@@ -30,11 +30,11 @@
 #include "vpx/vpx_decoder.h"
 #include "vpx/vp8dx.h"
 
-#define LOG_TAG "LIBVPX_DEC"
+#define LOG_TAG "vpx_jni"
 #define LOGE(...) ((void)__android_log_print(ANDROID_LOG_ERROR, LOG_TAG, \
                                              __VA_ARGS__))
 
-#define VPX_DECODER_FUNC(RETURN_TYPE, NAME, ...) \
+#define DECODER_FUNC(RETURN_TYPE, NAME, ...) \
   extern "C" { \
   JNIEXPORT RETURN_TYPE \
     Java_com_google_android_exoplayer2_ext_vp9_VpxDecoder_ ## NAME \
@@ -44,14 +44,14 @@
     Java_com_google_android_exoplayer2_ext_vp9_VpxDecoder_ ## NAME \
       (JNIEnv* env, jobject thiz, ##__VA_ARGS__)\
 
-#define VPX_NATIVE_LIBRARY_HELPER_FUNC(RETURN_TYPE, NAME, ...) \
+#define LIBRARY_FUNC(RETURN_TYPE, NAME, ...) \
   extern "C" { \
   JNIEXPORT RETURN_TYPE \
-    Java_com_google_android_exoplayer2_ext_vp9_VpxNativeLibraryHelper_ ## NAME \
+    Java_com_google_android_exoplayer2_ext_vp9_VpxLibrary_ ## NAME \
       (JNIEnv* env, jobject thiz, ##__VA_ARGS__);\
   } \
   JNIEXPORT RETURN_TYPE \
-    Java_com_google_android_exoplayer2_ext_vp9_VpxNativeLibraryHelper_ ## NAME \
+    Java_com_google_android_exoplayer2_ext_vp9_VpxLibrary_ ## NAME \
       (JNIEnv* env, jobject thiz, ##__VA_ARGS__)\
 
 // JNI references for VpxOutputBuffer class.
@@ -68,7 +68,7 @@ jint JNI_OnLoad(JavaVM* vm, void* reserved) {
   return JNI_VERSION_1_6;
 }
 
-VPX_DECODER_FUNC(jlong, vpxInit) {
+DECODER_FUNC(jlong, vpxInit) {
   vpx_codec_ctx_t* context = new vpx_codec_ctx_t();
   vpx_codec_dec_cfg_t cfg = {0, 0, 0};
   cfg.threads = android_getCpuCount();
@@ -91,7 +91,7 @@ VPX_DECODER_FUNC(jlong, vpxInit) {
   return reinterpret_cast<intptr_t>(context);
 }
 
-VPX_DECODER_FUNC(jlong, vpxDecode, jlong jContext, jobject encoded, jint len) {
+DECODER_FUNC(jlong, vpxDecode, jlong jContext, jobject encoded, jint len) {
   vpx_codec_ctx_t* const context = reinterpret_cast<vpx_codec_ctx_t*>(jContext);
   const uint8_t* const buffer =
       reinterpret_cast<const uint8_t*>(env->GetDirectBufferAddress(encoded));
@@ -104,14 +104,14 @@ VPX_DECODER_FUNC(jlong, vpxDecode, jlong jContext, jobject encoded, jint len) {
   return 0;
 }
 
-VPX_DECODER_FUNC(jlong, vpxClose, jlong jContext) {
+DECODER_FUNC(jlong, vpxClose, jlong jContext) {
   vpx_codec_ctx_t* const context = reinterpret_cast<vpx_codec_ctx_t*>(jContext);
   vpx_codec_destroy(context);
   delete context;
   return 0;
 }
 
-VPX_DECODER_FUNC(jint, vpxGetFrame, jlong jContext, jobject jOutputBuffer) {
+DECODER_FUNC(jint, vpxGetFrame, jlong jContext, jobject jOutputBuffer) {
   vpx_codec_ctx_t* const context = reinterpret_cast<vpx_codec_ctx_t*>(jContext);
   vpx_codec_iter_t iter = NULL;
   const vpx_image_t* const img = vpx_codec_get_frame(context, &iter);
@@ -176,16 +176,15 @@ VPX_DECODER_FUNC(jint, vpxGetFrame, jlong jContext, jobject jOutputBuffer) {
   return 0;
 }
 
-VPX_DECODER_FUNC(jstring, vpxGetErrorMessage, jlong jContext) {
+DECODER_FUNC(jstring, vpxGetErrorMessage, jlong jContext) {
   vpx_codec_ctx_t* const context = reinterpret_cast<vpx_codec_ctx_t*>(jContext);
   return env->NewStringUTF(vpx_codec_error(context));
 }
 
-VPX_NATIVE_LIBRARY_HELPER_FUNC(jstring, nativeGetLibvpxVersion) {
+LIBRARY_FUNC(jstring, vpxGetVersion) {
   return env->NewStringUTF(vpx_codec_version_str());
 }
 
-VPX_NATIVE_LIBRARY_HELPER_FUNC(jstring, nativeGetLibvpxConfig) {
+LIBRARY_FUNC(jstring, vpxGetBuildConfig) {
   return env->NewStringUTF(vpx_codec_build_config());
 }
-

extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxNativeLibraryHelper.java → library/src/main/java/com/google/android/exoplayer2/util/LibraryLoader.java

@@ -13,76 +13,50 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.google.android.exoplayer2.ext.vp9;
-
-import com.google.android.exoplayer2.util.Assertions;
+package com.google.android.exoplayer2.util;
 
 /**
- * Configure the native libraries that are used by the {@link VpxDecoder}.
+ * Configurable loader for native libraries.
  */
-public final class VpxNativeLibraryHelper {
-
-  private static boolean loadAttempted;
-  private static boolean isAvailable;
-  private static String[] nativeLibs = { "vpx", "vpxJNI" };
-
-  private static final Object lock = new Object();
-
-  private VpxNativeLibraryHelper() {}
+public final class LibraryLoader {
 
-  /**
-   * Override the default set of native libraries loaded for Vpx decoder support.
-   * If an application wishes to call this method, it must do so before calling any other method
-   * defined by this class, and before instantiating a {@link LibvpxVideoRenderer} instance.
-   */
-  public static void setNativeLibraries(String... libs) {
-    synchronized (lock) {
-      Assertions.checkState(!loadAttempted,
-          "Vpx native libs must be set earlier, they have already been loaded.");
-      nativeLibs = libs;
-    }
-  }
+  private String[] nativeLibraries;
+  private boolean loadAttempted;
+  private boolean isAvailable;
 
   /**
-   * Returns whether the underlying libvpx library is available.
+   * @param libraries The names of the libraries to load.
    */
-  public static boolean isLibvpxAvailable() {
-    return loadNativeLibraries();
+  public LibraryLoader(String... libraries) {
+    nativeLibraries = libraries;
   }
 
   /**
-   * Returns the version of the underlying libvpx library if available, otherwise {@code null}.
+   * Overrides the names of the libraries to load. Must be called before any call to
+   * {@link #isAvailable()}.
    */
-  public static String getLibvpxVersion() {
-    return isLibvpxAvailable() ? nativeGetLibvpxConfig() : null;
+  public synchronized void setLibraries(String... libraries) {
+    Assertions.checkState(!loadAttempted, "Cannot set libraries after loading");
+    nativeLibraries = libraries;
   }
 
   /**
-   * Returns the configuration string with which the underlying libvpx library was built.
+   * Returns whether the underlying libraries are available, loading them if necessary.
    */
-  public static String getLibvpxConfig() {
-    return isLibvpxAvailable() ? nativeGetLibvpxVersion() : null;
-  }
-
-  private static boolean loadNativeLibraries() {
-    synchronized (lock) {
-      if (loadAttempted) {
-        return isAvailable;
-      }
-
-      loadAttempted = true;
-      try {
-        for (String lib : VpxNativeLibraryHelper.nativeLibs) {
-          System.loadLibrary(lib);
-        }
-        isAvailable = true;
-      } catch (UnsatisfiedLinkError exception) {
-        isAvailable = false;
-      }
+  public synchronized boolean isAvailable() {
+    if (loadAttempted) {
       return isAvailable;
     }
+    loadAttempted = true;
+    try {
+      for (String lib : nativeLibraries) {
+        System.loadLibrary(lib);
+      }
+      isAvailable = true;
+    } catch (UnsatisfiedLinkError exception) {
+      // Do nothing.
+    }
+    return isAvailable;
   }
 
-  private static native String nativeGetLibvpxConfig();
-  private static native String nativeGetLibvpxVersion();
 }