diff --git a/src/starboard/shared/ffmpeg/ffmpeg_audio_decoder_impl.cc b/src/starboard/shared/ffmpeg/ffmpeg_audio_decoder_impl.cc
new file mode 100644
index 0000000..ec1f8f9
--- /dev/null
+++ b/src/starboard/shared/ffmpeg/ffmpeg_audio_decoder_impl.cc
@@ -0,0 +1,327 @@
+// Copyright 2018 Google Inc. All Rights Reserved.
+//
+// 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.
+
+// This file contains the explicit specialization of the AudioDecoderImpl class
+// for the value 'FFMPEG'.
+
+#include "starboard/shared/ffmpeg/ffmpeg_audio_decoder_impl.h"
+
+#include "starboard/audio_sink.h"
+#include "starboard/log.h"
+#include "starboard/memory.h"
+#include "starboard/shared/starboard/media/media_util.h"
+
+namespace starboard {
+namespace shared {
+namespace ffmpeg {
+
+namespace {
+
+SbMediaAudioSampleType GetSupportedSampleType() {
+  if (SbAudioSinkIsAudioSampleTypeSupported(kSbMediaAudioSampleTypeFloat32)) {
+    return kSbMediaAudioSampleTypeFloat32;
+  }
+  return kSbMediaAudioSampleTypeInt16Deprecated;
+}
+
+AVCodecID GetFfmpegCodecIdByMediaCodec(SbMediaAudioCodec audio_codec) {
+  switch (audio_codec) {
+    case kSbMediaAudioCodecAac:
+      return AV_CODEC_ID_AAC;
+    case kSbMediaAudioCodecOpus:
+      return AV_CODEC_ID_OPUS;
+    default:
+      return AV_CODEC_ID_NONE;
+  }
+}
+
+const bool g_registered =
+    FFMPEGDispatch::RegisterSpecialization(FFMPEG,
+                                           LIBAVCODEC_VERSION_MAJOR,
+                                           LIBAVFORMAT_VERSION_MAJOR,
+                                           LIBAVUTIL_VERSION_MAJOR);
+
+}  // namespace
+
+AudioDecoderImpl<FFMPEG>::AudioDecoderImpl(
+    SbMediaAudioCodec audio_codec,
+    const SbMediaAudioHeader& audio_header)
+    : audio_codec_(audio_codec),
+      codec_context_(NULL),
+      av_frame_(NULL),
+      stream_ended_(false),
+      audio_header_(audio_header) {
+  SB_DCHECK(g_registered) << "Decoder Specialization registration failed.";
+  SB_DCHECK(GetFfmpegCodecIdByMediaCodec(audio_codec) != AV_CODEC_ID_NONE)
+      << "Unsupported audio codec " << audio_codec;
+  ffmpeg_ = FFMPEGDispatch::GetInstance();
+  SB_DCHECK(ffmpeg_);
+  if ((ffmpeg_->specialization_version()) == FFMPEG) {
+    InitializeCodec();
+  }
+}
+
+AudioDecoderImpl<FFMPEG>::~AudioDecoderImpl() {
+  TeardownCodec();
+}
+
+// static
+AudioDecoder* AudioDecoderImpl<FFMPEG>::Create(
+    SbMediaAudioCodec audio_codec,
+    const SbMediaAudioHeader& audio_header) {
+  return new AudioDecoderImpl<FFMPEG>(audio_codec, audio_header);
+}
+
+void AudioDecoderImpl<FFMPEG>::Initialize(const OutputCB& output_cb,
+                                          const ErrorCB& error_cb) {
+  SB_DCHECK(BelongsToCurrentThread());
+  SB_DCHECK(output_cb);
+  SB_DCHECK(!output_cb_);
+  SB_DCHECK(error_cb);
+  SB_DCHECK(!error_cb_);
+
+  output_cb_ = output_cb;
+  error_cb_ = error_cb;
+}
+
+void AudioDecoderImpl<FFMPEG>::Decode(
+    const scoped_refptr<InputBuffer>& input_buffer,
+    const ConsumedCB& consumed_cb) {
+  SB_DCHECK(BelongsToCurrentThread());
+  SB_DCHECK(input_buffer);
+  SB_DCHECK(output_cb_);
+  SB_CHECK(codec_context_ != NULL);
+
+  Schedule(consumed_cb);
+
+  if (stream_ended_) {
+    SB_LOG(ERROR) << "Decode() is called after WriteEndOfStream() is called.";
+    return;
+  }
+
+  AVPacket packet;
+  ffmpeg_->av_init_packet(&packet);
+  packet.data = const_cast<uint8_t*>(input_buffer->data());
+  packet.size = input_buffer->size();
+
+#if LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(52, 8, 0)
+  ffmpeg_->av_frame_unref(av_frame_);
+#else   // LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(52, 8, 0)
+  ffmpeg_->avcodec_get_frame_defaults(av_frame_);
+#endif  // LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(52, 8, 0)
+  int frame_decoded = 0;
+  int result = ffmpeg_->avcodec_decode_audio4(codec_context_, av_frame_,
+                                              &frame_decoded, &packet);
+  if (result != input_buffer->size()) {
+    // TODO: Consider fill it with silence.
+    SB_DLOG(WARNING) << "avcodec_decode_audio4() failed with result: " << result
+                     << " with input buffer size: " << input_buffer->size()
+                     << " and frame decoded: " << frame_decoded;
+    error_cb_();
+    return;
+  }
+
+  if (frame_decoded != 1) {
+    // TODO: Adjust timestamp accordingly when decoding result is shifted.
+    SB_DCHECK(frame_decoded == 0);
+    SB_DLOG(WARNING) << "avcodec_decode_audio4() returns with 0 frames decoded";
+    return;
+  }
+
+  int decoded_audio_size = ffmpeg_->av_samples_get_buffer_size(
+      NULL, codec_context_->channels, av_frame_->nb_samples,
+      codec_context_->sample_fmt, 1);
+  audio_header_.samples_per_second = codec_context_->sample_rate;
+
+  if (decoded_audio_size > 0) {
+    scoped_refptr<DecodedAudio> decoded_audio = new DecodedAudio(
+        codec_context_->channels, GetSampleType(), GetStorageType(),
+        input_buffer->timestamp(),
+        codec_context_->channels * av_frame_->nb_samples *
+            starboard::media::GetBytesPerSample(GetSampleType()));
+    if (GetStorageType() == kSbMediaAudioFrameStorageTypeInterleaved) {
+      SbMemoryCopy(decoded_audio->buffer(), *av_frame_->extended_data,
+                   decoded_audio->size());
+    } else {
+      SB_DCHECK(GetStorageType() == kSbMediaAudioFrameStorageTypePlanar);
+      const int per_channel_size_in_bytes =
+          decoded_audio->size() / decoded_audio->channels();
+      for (int i = 0; i < decoded_audio->channels(); ++i) {
+        SbMemoryCopy(decoded_audio->buffer() + per_channel_size_in_bytes * i,
+                     av_frame_->extended_data[i], per_channel_size_in_bytes);
+      }
+    }
+    decoded_audios_.push(decoded_audio);
+    Schedule(output_cb_);
+  } else {
+    // TODO: Consider fill it with silence.
+    SB_LOG(ERROR) << "Decoded audio frame is empty.";
+  }
+}
+
+void AudioDecoderImpl<FFMPEG>::WriteEndOfStream() {
+  SB_DCHECK(BelongsToCurrentThread());
+  SB_DCHECK(output_cb_);
+
+  // AAC has no dependent frames so we needn't flush the decoder.  Set the flag
+  // to ensure that Decode() is not called when the stream is ended.
+  stream_ended_ = true;
+  // Put EOS into the queue.
+  decoded_audios_.push(new DecodedAudio);
+
+  Schedule(output_cb_);
+}
+
+scoped_refptr<AudioDecoderImpl<FFMPEG>::DecodedAudio>
+AudioDecoderImpl<FFMPEG>::Read() {
+  SB_DCHECK(BelongsToCurrentThread());
+  SB_DCHECK(output_cb_);
+  SB_DCHECK(!decoded_audios_.empty());
+
+  scoped_refptr<DecodedAudio> result;
+  if (!decoded_audios_.empty()) {
+    result = decoded_audios_.front();
+    decoded_audios_.pop();
+  }
+  return result;
+}
+
+void AudioDecoderImpl<FFMPEG>::Reset() {
+  SB_DCHECK(BelongsToCurrentThread());
+
+  stream_ended_ = false;
+  while (!decoded_audios_.empty()) {
+    decoded_audios_.pop();
+  }
+
+  CancelPendingJobs();
+}
+
+bool AudioDecoderImpl<FFMPEG>::is_valid() const {
+  return (ffmpeg_ != NULL) && ffmpeg_->is_valid() && (codec_context_ != NULL);
+}
+
+SbMediaAudioSampleType AudioDecoderImpl<FFMPEG>::GetSampleType() const {
+  SB_DCHECK(BelongsToCurrentThread());
+
+  if (codec_context_->sample_fmt == AV_SAMPLE_FMT_S16 ||
+      codec_context_->sample_fmt == AV_SAMPLE_FMT_S16P) {
+    return kSbMediaAudioSampleTypeInt16Deprecated;
+  } else if (codec_context_->sample_fmt == AV_SAMPLE_FMT_FLT ||
+             codec_context_->sample_fmt == AV_SAMPLE_FMT_FLTP) {
+    return kSbMediaAudioSampleTypeFloat32;
+  }
+
+  SB_NOTREACHED();
+
+  return kSbMediaAudioSampleTypeFloat32;
+}
+
+SbMediaAudioFrameStorageType AudioDecoderImpl<FFMPEG>::GetStorageType() const {
+  SB_DCHECK(BelongsToCurrentThread());
+
+  if (codec_context_->sample_fmt == AV_SAMPLE_FMT_S16 ||
+      codec_context_->sample_fmt == AV_SAMPLE_FMT_FLT) {
+    return kSbMediaAudioFrameStorageTypeInterleaved;
+  }
+  if (codec_context_->sample_fmt == AV_SAMPLE_FMT_S16P ||
+      codec_context_->sample_fmt == AV_SAMPLE_FMT_FLTP) {
+    return kSbMediaAudioFrameStorageTypePlanar;
+  }
+
+  SB_NOTREACHED();
+  return kSbMediaAudioFrameStorageTypeInterleaved;
+}
+
+int AudioDecoderImpl<FFMPEG>::GetSamplesPerSecond() const {
+  return audio_header_.samples_per_second;
+}
+
+void AudioDecoderImpl<FFMPEG>::InitializeCodec() {
+  codec_context_ = ffmpeg_->avcodec_alloc_context3(NULL);
+
+  if (codec_context_ == NULL) {
+    SB_LOG(ERROR) << "Unable to allocate ffmpeg codec context";
+    return;
+  }
+
+  codec_context_->codec_type = AVMEDIA_TYPE_AUDIO;
+  codec_context_->codec_id = GetFfmpegCodecIdByMediaCodec(audio_codec_);
+  // Request_sample_fmt is set by us, but sample_fmt is set by the decoder.
+  if (GetSupportedSampleType() == kSbMediaAudioSampleTypeInt16Deprecated) {
+    codec_context_->request_sample_fmt = AV_SAMPLE_FMT_S16;
+  } else {
+    codec_context_->request_sample_fmt = AV_SAMPLE_FMT_FLT;
+  }
+
+  codec_context_->channels = audio_header_.number_of_channels;
+  codec_context_->sample_rate = audio_header_.samples_per_second;
+  codec_context_->extradata = NULL;
+  codec_context_->extradata_size = 0;
+
+  if (codec_context_->codec_id == AV_CODEC_ID_OPUS &&
+      audio_header_.audio_specific_config_size > 0) {
+    // AV_INPUT_BUFFER_PADDING_SIZE is not defined in ancient avcodec.h.  Use a
+    // large enough padding here explicitly.
+    const int kAvInputBufferPaddingSize = 256;
+    codec_context_->extradata_size = audio_header_.audio_specific_config_size;
+    codec_context_->extradata = static_cast<uint8_t*>(ffmpeg_->av_malloc(
+        codec_context_->extradata_size + kAvInputBufferPaddingSize));
+    SB_DCHECK(codec_context_->extradata);
+    SbMemoryCopy(codec_context_->extradata, audio_header_.audio_specific_config,
+                 codec_context_->extradata_size);
+    SbMemorySet(codec_context_->extradata + codec_context_->extradata_size, 0,
+                kAvInputBufferPaddingSize);
+  }
+
+  AVCodec* codec = ffmpeg_->avcodec_find_decoder(codec_context_->codec_id);
+
+  if (codec == NULL) {
+    SB_LOG(ERROR) << "Unable to allocate ffmpeg codec context";
+    TeardownCodec();
+    return;
+  }
+
+  int rv = ffmpeg_->OpenCodec(codec_context_, codec);
+  if (rv < 0) {
+    SB_LOG(ERROR) << "Unable to open codec";
+    TeardownCodec();
+    return;
+  }
+
+#if LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(52, 8, 0)
+  av_frame_ = ffmpeg_->av_frame_alloc();
+#else   // LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(52, 8, 0)
+  av_frame_ = ffmpeg_->avcodec_alloc_frame();
+#endif  // LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(52, 8, 0)
+  if (av_frame_ == NULL) {
+    SB_LOG(ERROR) << "Unable to allocate audio frame";
+    TeardownCodec();
+  }
+}
+
+void AudioDecoderImpl<FFMPEG>::TeardownCodec() {
+  if (codec_context_) {
+    ffmpeg_->CloseCodec(codec_context_);
+    if (codec_context_->extradata_size) {
+      ffmpeg_->av_freep(&codec_context_->extradata);
+    }
+    ffmpeg_->av_freep(&codec_context_);
+  }
+  ffmpeg_->av_freep(&av_frame_);
+}
+
+}  // namespace ffmpeg
+}  // namespace shared
+}  // namespace starboard