1 files changed, 148 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/audio/AudioProcessor.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/audio/AudioProcessor.java
new file mode 100644
index 0000000000..e0814314ca
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/audio/AudioProcessor.java
@@ -0,0 +1,148 @@
+/*
+ * 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 org.mozilla.thirdparty.com.google.android.exoplayer2.audio;
+
+import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.Format;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+
+/**
+ * Interface for audio processors, which take audio data as input and transform it, potentially
+ * modifying its channel count, encoding and/or sample rate.
+ *
+ * <p>In addition to being able to modify the format of audio, implementations may allow parameters
+ * to be set that affect the output audio and whether the processor is active/inactive.
+ */
+public interface AudioProcessor {
+
+  /** PCM audio format that may be handled by an audio processor. */
+  final class AudioFormat {
+    public static final AudioFormat NOT_SET =
+        new AudioFormat(
+            /* sampleRate= */ Format.NO_VALUE,
+            /* channelCount= */ Format.NO_VALUE,
+            /* encoding= */ Format.NO_VALUE);
+
+    /** The sample rate in Hertz. */
+    public final int sampleRate;
+    /** The number of interleaved channels. */
+    public final int channelCount;
+    /** The type of linear PCM encoding. */
+    @C.PcmEncoding public final int encoding;
+    /** The number of bytes used to represent one audio frame. */
+    public final int bytesPerFrame;
+
+    public AudioFormat(int sampleRate, int channelCount, @C.PcmEncoding int encoding) {
+      this.sampleRate = sampleRate;
+      this.channelCount = channelCount;
+      this.encoding = encoding;
+      bytesPerFrame =
+          Util.isEncodingLinearPcm(encoding)
+              ? Util.getPcmFrameSize(encoding, channelCount)
+              : Format.NO_VALUE;
+    }
+
+    @Override
+    public String toString() {
+      return "AudioFormat["
+          + "sampleRate="
+          + sampleRate
+          + ", channelCount="
+          + channelCount
+          + ", encoding="
+          + encoding
+          + ']';
+    }
+  }
+
+  /** Exception thrown when a processor can't be configured for a given input audio format. */
+  final class UnhandledAudioFormatException extends Exception {
+
+    public UnhandledAudioFormatException(AudioFormat inputAudioFormat) {
+      super("Unhandled format: " + inputAudioFormat);
+    }
+
+  }
+
+  /** An empty, direct {@link ByteBuffer}. */
+  ByteBuffer EMPTY_BUFFER = ByteBuffer.allocateDirect(0).order(ByteOrder.nativeOrder());
+
+  /**
+   * Configures the processor to process input audio with the specified format. After calling this
+   * method, call {@link #isActive()} to determine whether the audio processor is active. Returns
+   * the configured output audio format if this instance is active.
+   *
+   * <p>After calling this method, it is necessary to {@link #flush()} the processor to apply the
+   * new configuration. Before applying the new configuration, it is safe to queue input and get
+   * output in the old input/output formats. Call {@link #queueEndOfStream()} when no more input
+   * will be supplied in the old input format.
+   *
+   * @param inputAudioFormat The format of audio that will be queued after the next call to {@link
+   *     #flush()}.
+   * @return The configured output audio format if this instance is {@link #isActive() active}.
+   * @throws UnhandledAudioFormatException Thrown if the specified format can't be handled as input.
+   */
+  AudioFormat configure(AudioFormat inputAudioFormat) throws UnhandledAudioFormatException;
+
+  /** Returns whether the processor is configured and will process input buffers. */
+  boolean isActive();
+
+  /**
+   * Queues audio data between the position and limit of the input {@code buffer} for processing.
+   * {@code buffer} must be a direct byte buffer with native byte order. Its contents are treated as
+   * read-only. Its position will be advanced by the number of bytes consumed (which may be zero).
+   * The caller retains ownership of the provided buffer. Calling this method invalidates any
+   * previous buffer returned by {@link #getOutput()}.
+   *
+   * @param buffer The input buffer to process.
+   */
+  void queueInput(ByteBuffer buffer);
+
+  /**
+   * Queues an end of stream signal. After this method has been called,
+   * {@link #queueInput(ByteBuffer)} may not be called until after the next call to
+   * {@link #flush()}. Calling {@link #getOutput()} will return any remaining output data. Multiple
+   * calls may be required to read all of the remaining output data. {@link #isEnded()} will return
+   * {@code true} once all remaining output data has been read.
+   */
+  void queueEndOfStream();
+
+  /**
+   * Returns a buffer containing processed output data between its position and limit. The buffer
+   * will always be a direct byte buffer with native byte order. Calling this method invalidates any
+   * previously returned buffer. The buffer will be empty if no output is available.
+   *
+   * @return A buffer containing processed output data between its position and limit.
+   */
+  ByteBuffer getOutput();
+
+  /**
+   * Returns whether this processor will return no more output from {@link #getOutput()} until it
+   * has been {@link #flush()}ed and more input has been queued.
+   */
+  boolean isEnded();
+
+  /**
+   * Clears any buffered data and pending output. If the audio processor is active, also prepares
+   * the audio processor to receive a new stream of input in the last configured (pending) format.
+   */
+  void flush();
+
+  /** Resets the processor to its unconfigured state, releasing any resources. */
+  void reset();
+}