[Chromecast] Move CastAudioDecoder out to chromecast/media/cma/decoder

chromecast/media/base/cast_audio_decoder_linux.cc

Index: chromecast/media/base/cast_audio_decoder_linux.cc
diff --git a/chromecast/media/base/cast_audio_decoder_linux.cc b/chromecast/media/base/cast_audio_decoder_linux.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e45de379e195724ff86fa089ad42b32a07679abf
--- /dev/null
+++ b/chromecast/media/base/cast_audio_decoder_linux.cc
@@ -0,0 +1,315 @@
+// Copyright 2015 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.
+
+#include "chromecast/media/base/cast_audio_decoder.h"
+
+#include <limits>
+#include <queue>
+#include <vector>
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/single_thread_task_runner.h"
+#include "base/trace_event/trace_event.h"
+#include "chromecast/media/base/decoder_buffer_base.h"
+#include "chromecast/media/cma/base/decoder_buffer_adapter.h"
+#include "chromecast/media/cma/base/decoder_config_adapter.h"
+#include "media/base/audio_buffer.h"
+#include "media/base/audio_bus.h"
+#include "media/base/cdm_context.h"
+#include "media/base/channel_layout.h"
+#include "media/base/channel_mixer.h"
+#include "media/base/decoder_buffer.h"
+#include "media/base/sample_format.h"
+#include "media/filters/ffmpeg_audio_decoder.h"
+#include "media/filters/opus_audio_decoder.h"
+
+namespace chromecast {
+
+namespace {
+
+const int kOpusSamplingRate = 48000;
+const uint8 kFakeOpusExtraData[19] = {
+  'O', 'p', 'u', 's', 'H', 'e', 'a', 'd',  // offset 0, OpusHead
+  0,  // offset 8, version
+  2,  // offset 9, channels
+  0, 0,  // offset 10, skip
+  static_cast<uint8>(kOpusSamplingRate & 0xFF),  // offset 12, LE
+  static_cast<uint8>((kOpusSamplingRate >> 8) & 0xFF),
+  static_cast<uint8>((kOpusSamplingRate >> 16) & 0xFF),
+  static_cast<uint8>((kOpusSamplingRate >> 24) & 0xFF),
+  0, 0,  // offset 16, gain
+  0,  // offset 18, stereo mapping
+};
+
+const int kOutputChannelCount = 2;  // Always output stereo audio.
+const int kMaxChannelInput = 2;
+
+// Copies a chromecast::media::DecoderBufferBase into a ::media::DecoderBuffer.
+// Currently required because FFmpegAudioDecoder only accepts
+// ::media::DecoderBuffer.
+scoped_refptr<::media::DecoderBuffer> ConvertToMediaDecoderBuffer(
+    const scoped_refptr<media::DecoderBufferBase>& input_buffer) {
+  if (input_buffer->end_of_stream())
+    return ::media::DecoderBuffer::CreateEOSBuffer();
+
+  scoped_refptr<::media::DecoderBuffer> copy = ::media::DecoderBuffer::CopyFrom(
+      input_buffer->data(), input_buffer->data_size());
+  copy->set_timestamp(
+      base::TimeDelta::FromMicroseconds(input_buffer->timestamp()));
+  return copy;
+}
+
+class CastAudioDecoderImpl : public CastAudioDecoder {
+ public:
+  CastAudioDecoderImpl(
+      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
+      const InitializedCallback& initialized_callback,
+      OutputFormat output_format)
+      : task_runner_(task_runner),
+        initialized_callback_(initialized_callback),
+        output_format_(output_format),
+        initialized_(false),
+        decode_pending_(false),
+        weak_factory_(this) {}
+
+  ~CastAudioDecoderImpl() override {}
+
+  void Initialize(const media::AudioConfig& config) {
+    TRACE_EVENT0("cma", "CastAudioDecoderImpl::Initialize");
+    DCHECK(!initialized_);
+    DCHECK_LE(config_.channel_number, kMaxChannelInput);
+    config_ = config;
+    if (config_.channel_number == 1) {
+      // If the input is mono, create a ChannelMixer to convert mono to stereo.
+      // TODO(kmackay) Support other channel format conversions?
+      mixer_.reset(new ::media::ChannelMixer(::media::CHANNEL_LAYOUT_MONO,
+                                             ::media::CHANNEL_LAYOUT_STEREO));
+    }
+    base::WeakPtr<CastAudioDecoderImpl> self = weak_factory_.GetWeakPtr();
+    if (config.codec == media::kCodecOpus) {
+      // Insert fake extradata to make OpusAudioDecoder work with v2mirroring.
+      if (config_.extra_data.empty() &&
+          config_.samples_per_second == kOpusSamplingRate &&
+          config_.channel_number == 2)
+        config_.extra_data.assign(
+            kFakeOpusExtraData,
+            kFakeOpusExtraData + sizeof(kFakeOpusExtraData));
+      decoder_.reset(new ::media::OpusAudioDecoder(task_runner_));
+    } else {
+      decoder_.reset(new ::media::FFmpegAudioDecoder(
+          task_runner_, make_scoped_refptr(new ::media::MediaLog())));
+    }
+    decoder_->Initialize(
+        media::DecoderConfigAdapter::ToMediaAudioDecoderConfig(config_),
+#if !defined(CHROMECAST_BUILD)
+        ::media::SetCdmReadyCB(),
+#endif
+        base::Bind(&CastAudioDecoderImpl::OnInitialized, self),
+        base::Bind(&CastAudioDecoderImpl::OnDecoderOutput, self));
+    // Unfortunately there is no result from decoder_->Initialize() until later
+    // (the pipeline status callback is posted to the task runner).
+  }
+
+  // CastAudioDecoder implementation:
+  bool Decode(const scoped_refptr<media::DecoderBufferBase>& data,
+              const DecodeCallback& decode_callback) override {
+    TRACE_EVENT0("cma", "CastAudioDecoderImpl::Decode");
+    DCHECK(!decode_callback.is_null());
+    DCHECK(task_runner_->BelongsToCurrentThread());
+    if (!initialized_ || decode_pending_) {
+      decode_queue_.push(std::make_pair(data, decode_callback));
+    } else {
+      DecodeNow(data, decode_callback);
+    }
+    return true;
+  }
+
+ private:
+  typedef std::pair<scoped_refptr<media::DecoderBufferBase>, DecodeCallback>
+      DecodeBufferCallbackPair;
+
+  void DecodeNow(const scoped_refptr<media::DecoderBufferBase>& data,
+                 const DecodeCallback& decode_callback) {
+    if (data->end_of_stream()) {
+      // Post the task to ensure that |decode_callback| is not called from
+      // within a call to Decode().
+      task_runner_->PostTask(FROM_HERE,
+                             base::Bind(decode_callback, kDecodeOk, data));
+      return;
+    }
+
+    // FFmpegAudioDecoder requires a timestamp to be set, in order to workaround
+    // an FFmpeg bug that was fixed in 2012 :/
+    base::TimeDelta timestamp =
+        base::TimeDelta::FromMicroseconds(data->timestamp());
+    if (timestamp == ::media::kNoTimestamp())
+      data->set_timestamp(base::TimeDelta());
+
+    decode_pending_ = true;
+    // TODO(kmackay) Instead of copying the data to a ::media::DecoderBuffer,
+    // do this more efficiently somehow. Potentially add a method to
+    // FFmpegAudioDecoder to take raw uint8_t* buffers.
+    decoder_->Decode(
+        ConvertToMediaDecoderBuffer(data),
+        base::Bind(&CastAudioDecoderImpl::OnDecodeStatus,
+                   weak_factory_.GetWeakPtr(), timestamp, decode_callback));
+  }
+
+  void OnInitialized(bool success) {
+    TRACE_EVENT0("cma", "CastAudioDecoderImpl::OnInitialize");
+    DCHECK(!initialized_);
+    LOG_IF(ERROR, !success) << "Failed to initialize FFmpegAudioDecoder";
+    if (success)
+      initialized_ = true;
+
+    if (success && !decode_queue_.empty()) {
+      const auto& d = decode_queue_.front();
+      DecodeNow(d.first, d.second);
+      decode_queue_.pop();
+    }
+
+    if (!initialized_callback_.is_null())
+      initialized_callback_.Run(initialized_);
+  }
+
+  void OnDecodeStatus(base::TimeDelta buffer_timestamp,
+                      const DecodeCallback& decode_callback,
+                      ::media::AudioDecoder::Status status) {
+    TRACE_EVENT0("cma", "CastAudioDecoderImpl::OnDecodeStatus");
+    Status result_status = kDecodeOk;
+    scoped_refptr<media::DecoderBufferBase> decoded;
+    if (status == ::media::AudioDecoder::kOk && !decoded_chunks_.empty()) {
+      decoded = ConvertDecoded();
+    } else {
+      if (status != ::media::AudioDecoder::kOk)
+        result_status = kDecodeError;
+      decoded = new media::DecoderBufferAdapter(config_.id,
+                                                new ::media::DecoderBuffer(0));
+    }
+    decoded_chunks_.clear();
+    decoded->set_timestamp(buffer_timestamp);
+    decode_callback.Run(result_status, decoded);
+
+    // Do not reset decode_pending_ to false until after the callback has
+    // finished running because the callback may call Decode().
+    decode_pending_ = false;
+
+    if (decode_queue_.empty())
+      return;
+
+    const auto& d = decode_queue_.front();
+    // Calling DecodeNow() here does not result in a loop, because
+    // OnDecodeStatus() is always called asynchronously (guaranteed by the
+    // AudioDecoder interface).
+    DecodeNow(d.first, d.second);
+    decode_queue_.pop();
+  }
+
+  void OnDecoderOutput(const scoped_refptr<::media::AudioBuffer>& decoded) {
+    decoded_chunks_.push_back(decoded);
+  }
+
+  scoped_refptr<media::DecoderBufferBase> ConvertDecoded() {
+    DCHECK(!decoded_chunks_.empty());
+    int num_frames = 0;
+    for (auto& chunk : decoded_chunks_)
+      num_frames += chunk->frame_count();
+
+    // Copy decoded data into an AudioBus for conversion.
+    scoped_ptr<::media::AudioBus> decoded =
+        ::media::AudioBus::Create(config_.channel_number, num_frames);
+    int bus_frame_offset = 0;
+    for (auto& chunk : decoded_chunks_) {
+      chunk->ReadFrames(chunk->frame_count(), 0, bus_frame_offset,
+                        decoded.get());
+      bus_frame_offset += chunk->frame_count();
+    }
+
+    if (mixer_) {
+      // Convert to stereo if necessary.
+      scoped_ptr<::media::AudioBus> converted_to_stereo =
+          ::media::AudioBus::Create(kOutputChannelCount, num_frames);
+      mixer_->Transform(decoded.get(), converted_to_stereo.get());
+      decoded.swap(converted_to_stereo);
+    }
+
+    // Convert to the desired output format.
+    return FinishConversion(decoded.get());
+  }
+
+  scoped_refptr<media::DecoderBufferBase> FinishConversion(
+      ::media::AudioBus* bus) {
+    DCHECK_EQ(kOutputChannelCount, bus->channels());
+    int size = bus->frames() * kOutputChannelCount *
+               OutputFormatSizeInBytes(output_format_);
+    scoped_refptr<::media::DecoderBuffer> result(
+        new ::media::DecoderBuffer(size));
+
+    if (output_format_ == kOutputSigned16) {
+      bus->ToInterleaved(bus->frames(), OutputFormatSizeInBytes(output_format_),
+                         result->writable_data());
+    } else if (output_format_ == kOutputPlanarFloat) {
+      // Data in an AudioBus is already in planar float format; just copy each
+      // channel into the result buffer in order.
+      float* ptr = reinterpret_cast<float*>(result->writable_data());
+      for (int c = 0; c < bus->channels(); ++c) {
+        memcpy(ptr, bus->channel(c), bus->frames() * sizeof(float));
+        ptr += bus->frames();
+      }
+    } else {
+      NOTREACHED();
+    }
+
+    result->set_duration(base::TimeDelta::FromMicroseconds(
+        bus->frames() * base::Time::kMicrosecondsPerSecond /
+        config_.samples_per_second));
+    return make_scoped_refptr(
+        new media::DecoderBufferAdapter(config_.id, result));
+  }
+
+  const scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+  InitializedCallback initialized_callback_;
+  OutputFormat output_format_;
+  media::AudioConfig config_;
+  scoped_ptr<::media::AudioDecoder> decoder_;
+  std::queue<DecodeBufferCallbackPair> decode_queue_;
+  bool initialized_;
+  scoped_ptr<::media::ChannelMixer> mixer_;
+  bool decode_pending_;
+  std::vector<scoped_refptr<::media::AudioBuffer>> decoded_chunks_;
+  base::WeakPtrFactory<CastAudioDecoderImpl> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(CastAudioDecoderImpl);
+};
+
+}  // namespace
+
+// static
+scoped_ptr<CastAudioDecoder> CastAudioDecoder::Create(
+    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
+    const media::AudioConfig& config,
+    OutputFormat output_format,
+    const InitializedCallback& initialized_callback) {
+  scoped_ptr<CastAudioDecoderImpl> decoder(new CastAudioDecoderImpl(
+      task_runner, initialized_callback, output_format));
+  decoder->Initialize(config);
+  return decoder.Pass();
+}
+
+// static
+int CastAudioDecoder::OutputFormatSizeInBytes(
+    CastAudioDecoder::OutputFormat format) {
+  switch (format) {
+    case CastAudioDecoder::OutputFormat::kOutputSigned16:
+      return 2;
+    case CastAudioDecoder::OutputFormat::kOutputPlanarFloat:
+      return 4;
+  }
+  NOTREACHED();
+  return 1;
+}
+
+}  // namespace chromecast