Replace WebAudio MediaCodec usage with FFmpeg. A ~4x improvement.

media/base/android/webaudio_media_codec_bridge.h

-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef MEDIA_BASE_ANDROID_WEBAUDIO_MEDIA_CODEC_BRIDGE_H_
-#define MEDIA_BASE_ANDROID_WEBAUDIO_MEDIA_CODEC_BRIDGE_H_
-
-#include <jni.h>
-#include <stdint.h>
-
-#include "base/android/scoped_java_ref.h"
-#include "base/callback.h"
-#include "base/file_descriptor_posix.h"
-#include "base/macros.h"
-#include "base/memory/shared_memory.h"
-#include "media/base/media_export.h"
-
-namespace media {
-
-// This class serves as a bridge for native code to call Java
-// functions in the Android MediaCodec class. See
-// http://developer.android.com/reference/android/media/MediaCodec.html.
-class MEDIA_EXPORT WebAudioMediaCodecBridge {
- public:
-  // Create the bridge with the given file descriptors. We read from
-  // |encoded_audio_handle| to get the encoded audio data. Audio file
-  // information and decoded PCM samples are written to |pcm_output|.
-  // We also take ownership of |pcm_output|.
-  WebAudioMediaCodecBridge(base::SharedMemoryHandle encoded_audio_handle,
-                           base::FileDescriptor pcm_output,
-                           uint32_t data_size);
-  ~WebAudioMediaCodecBridge();
-
-  // Inform JNI about this bridge. Returns true if registration
-  // succeeded.
-  static bool RegisterWebAudioMediaCodecBridge(JNIEnv* env);
-
-  // Start MediaCodec to process the encoded data in
-  // |encoded_audio_handle|. The PCM samples are sent to |pcm_output|.
-  static void RunWebAudioMediaCodec(
-      base::SharedMemoryHandle encoded_audio_handle,
-      base::FileDescriptor pcm_output,
-      uint32_t data_size,
-      base::Closure on_decode_finished_cb);
-
-  void OnChunkDecoded(
-      JNIEnv* env,
-      const base::android::JavaParamRef<jobject>& /*java object*/,
-      const base::android::JavaParamRef<jobject>& buf,
-      jint buf_size,
-      jint input_channel_count,
-      jint output_channel_count);
-
-  void InitializeDestination(
-      JNIEnv* env,
-      const base::android::JavaParamRef<jobject>& /*java object*/,
-      jint channel_count,
-      jint sample_rate,
-      jlong duration_us);
-
- private:
-  // Handles MediaCodec processing of the encoded data in
-  // |encoded_audio_handle_| and sends the pcm data to |pcm_output_|.
-  // Returns true if decoding was successful.
-  bool DecodeInMemoryAudioFile();
-
-  // Save encoded audio data to a temporary file and return the file
-  // descriptor to that file.  -1 is returned if the audio data could
-  // not be saved for any reason.
-  int SaveEncodedAudioToFile(JNIEnv*, jobject);
-
-  // The encoded audio data is read from this file descriptor for the
-  // shared memory that holds the encoded data.
-  base::SharedMemoryHandle encoded_audio_handle_;
-
-  // The audio file information and decoded pcm data are written to
-  // this file descriptor. We take ownership of this descriptor.
-  int pcm_output_;
-
-  // The length of the encoded data.
-  uint32_t data_size_;
-
-  DISALLOW_COPY_AND_ASSIGN(WebAudioMediaCodecBridge);
-};
-
-}  // namespace media
-#endif  // MEDIA_BASE_ANDROID_WEBAUDIO_MEDIA_CODEC_BRIDGE_H_