1 files changed, 127 insertions, 0 deletions
diff --git a/src/com/android/exoplayer2/ext/ffmpeg/FfmpegAudioDecoder.java b/src/com/android/exoplayer2/ext/ffmpeg/FfmpegAudioDecoder.java
new file mode 100644
index 00000000..2b7817dc
--- /dev/null
+++ b/src/com/android/exoplayer2/ext/ffmpeg/FfmpegAudioDecoder.java
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2017 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 android.content.Context;
+import android.content.pm.PackageManager;
+import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
+import com.google.android.exoplayer2.decoder.SimpleOutputBuffer;
+import com.google.android.exoplayer2.util.MimeTypes;
+import com.android.tv.common.SoftPreconditions;
+
+import java.nio.ByteBuffer;
+
+/**
+ * Audio decoder which uses ffmpeg extension of ExoPlayer2. Since {@link FfmpegDecoder} is package
+ * private, expose the decoder via this class. Supported formats are AC3 and MP2.
+ */
+public class FfmpegAudioDecoder {
+    private static final int NUM_DECODER_BUFFERS = 1;
+
+    // The largest AC3 sample size. This is bigger than the largest MP2 sample size (1729).
+    private static final int INITIAL_INPUT_BUFFER_SIZE = 2560;
+    private static boolean AVAILABLE;
+
+    static {
+        AVAILABLE =
+                FfmpegLibrary.supportsFormat(MimeTypes.AUDIO_AC3)
+                        && FfmpegLibrary.supportsFormat(MimeTypes.AUDIO_MPEG_L2);
+    }
+
+    private FfmpegDecoder mDecoder;
+    private DecoderInputBuffer mInputBuffer;
+    private SimpleOutputBuffer mOutputBuffer;
+    private boolean mStarted;
+
+    /** Return whether Ffmpeg based software audio decoder is available. */
+    public static boolean isAvailable() {
+        return AVAILABLE;
+    }
+
+    /** Creates an Ffmpeg based software audio decoder. */
+    public FfmpegAudioDecoder(Context context) {
+        if (context.checkSelfPermission("android.permission.INTERNET")
+                == PackageManager.PERMISSION_GRANTED) {
+            throw new IllegalStateException("This code should run in an isolated process");
+        }
+    }
+
+    /**
+     * Decodes an audio sample.
+     *
+     * @param timeUs presentation timestamp of the sample
+     * @param sample data
+     */
+    public void decode(long timeUs, byte[] sample) {
+        SoftPreconditions.checkState(AVAILABLE);
+        mInputBuffer.data.clear();
+        mInputBuffer.data.put(sample);
+        mInputBuffer.data.flip();
+        mInputBuffer.timeUs = timeUs;
+        mDecoder.decode(mInputBuffer, mOutputBuffer, !mStarted);
+        if (!mStarted) {
+            mStarted = true;
+        }
+    }
+
+    /** Returns a decoded sample from decoder. */
+    public ByteBuffer getDecodedSample() {
+        return mOutputBuffer.data;
+    }
+
+    /** Returns the presentation time for the decoded sample. */
+    public long getDecodedTimeUs() {
+        return mOutputBuffer.timeUs;
+    }
+
+    /**
+     * Clear previous decode state if any. Prepares to decode samples of the specified encoding.
+     * This method should be called before using decode.
+     *
+     * @param mime audio encoding
+     */
+    public void resetDecoderState(String mime) {
+        SoftPreconditions.checkState(AVAILABLE);
+        release();
+        try {
+            mDecoder =
+                    new FfmpegDecoder(
+                            NUM_DECODER_BUFFERS,
+                            NUM_DECODER_BUFFERS,
+                            INITIAL_INPUT_BUFFER_SIZE,
+                            mime,
+                            null);
+            mStarted = false;
+            mInputBuffer = mDecoder.createInputBuffer();
+            // Since native JNI requires direct buffer, we should allocate it by #allocateDirect.
+            mInputBuffer.data = ByteBuffer.allocateDirect(INITIAL_INPUT_BUFFER_SIZE);
+            mOutputBuffer = mDecoder.createOutputBuffer();
+        } catch (FfmpegDecoderException e) {
+            // if AVAILABLE is {@code true}, this will not happen.
+        }
+    }
+
+    /** Releases all the resource. */
+    public void release() {
+        SoftPreconditions.checkState(AVAILABLE);
+        if (mDecoder != null) {
+            mDecoder.release();
+            mInputBuffer = null;
+            mOutputBuffer = null;
+            mDecoder = null;
+        }
+    }
+}