[chromecast] Remove //media dep from AudioFader and AudioClockSimulator.

AudioFader and AudioClockSimulator are used by multizone/sync.

Bug: b/152069660
Change-Id: I0bcf8068c1fa0dacae3330bcdde8aa8878aac253
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2138119
Commit-Queue: Qingwen Pi <qwp@google.com>
Reviewed-by: Kenneth MacKay <kmackay@chromium.org>
Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757153}

chromecast/media/audio/BUILD.gn

@@ -29,6 +29,20 @@ cast_source_set("processing") {
     "audio_fader.cc",
     "audio_fader.h",
     "audio_provider.h",
+    "cast_audio_bus.cc",
+    "cast_audio_bus.h",
+  ]
+
+  deps = [ "//base" ]
+
+  # Use fastest possible float math.
+  configs -= [ "//build/config/compiler:default_optimization" ]
+  configs += [ "//build/config/compiler:optimize_speed" ]
+  cflags = [ "-ffast-math" ]
+}
+
+cast_source_set("interleaved_channel_mixer") {
+  sources = [
     "interleaved_channel_mixer.cc",
     "interleaved_channel_mixer.h",
   ]
@@ -37,11 +51,6 @@ cast_source_set("processing") {
     "//base",
     "//media",
   ]
-
-  # Use fastest possible float math.
-  configs -= [ "//build/config/compiler:default_optimization" ]
-  configs += [ "//build/config/compiler:optimize_speed" ]
-  cflags = [ "-ffast-math" ]
 }
 
 cast_source_set("audio") {
@@ -164,6 +173,7 @@ cast_source_set("unittests") {
   ]
 
   deps = [
+    ":interleaved_channel_mixer",
     ":processing",
     "//base",
     "//media",

chromecast/media/audio/audio_clock_simulator.cc

@@ -8,7 +8,6 @@
 #include <cmath>
 
 #include "base/logging.h"
-#include "media/base/audio_bus.h"
 
 namespace chromecast {
 namespace media {
@@ -23,7 +22,7 @@ AudioClockSimulator::AudioClockSimulator(AudioProvider* provider)
       sample_rate_(provider_->sample_rate()),
       num_channels_(provider_->num_channels()),
       scratch_buffer_(
-          ::media::AudioBus::Create(num_channels_, kInterpolateWindow + 1)) {
+          CastAudioBus::Create(num_channels_, kInterpolateWindow + 1)) {
   DCHECK(provider_);
   DCHECK_GT(sample_rate_, 0);
   DCHECK_GT(num_channels_, 0u);

chromecast/media/audio/audio_clock_simulator.h

@@ -10,10 +10,7 @@
 #include <memory>
 
 #include "chromecast/media/audio/audio_provider.h"
-
-namespace media {
-class AudioBus;
-}  // namespace media
+#include "chromecast/media/audio/cast_audio_bus.h"
 
 namespace chromecast {
 namespace media {
@@ -122,7 +119,7 @@ class AudioClockSimulator : public AudioProvider {
   //     to interpolation.
   // The |first_frame_filled_| member var tracks whether or not the first frame
   // of the |scratch_buffer_| contains valid audio.
-  std::unique_ptr<::media::AudioBus> scratch_buffer_;
+  std::unique_ptr<CastAudioBus> scratch_buffer_;
 };
 
 }  // namespace media

chromecast/media/audio/audio_fader.cc

@@ -8,7 +8,6 @@
 
 #include "base/bits.h"
 #include "base/logging.h"
-#include "media/base/audio_bus.h"
 
 namespace chromecast {
 namespace media {
@@ -42,7 +41,7 @@ AudioFader::AudioFader(AudioProvider* provider,
   DCHECK_LE(num_channels_, kMaxChannels);
   DCHECK_GT(sample_rate_, 0);
 
-  fade_buffer_ = ::media::AudioBus::Create(num_channels_, fade_frames_);
+  fade_buffer_ = CastAudioBus::Create(num_channels_, fade_frames_);
   fade_buffer_->Zero();
 }
 

chromecast/media/audio/audio_fader.h

@@ -11,10 +11,7 @@
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "chromecast/media/audio/audio_provider.h"
-
-namespace media {
-class AudioBus;
-}  // namespace media
+#include "chromecast/media/audio/cast_audio_bus.h"
 
 namespace chromecast {
 namespace media {
@@ -87,7 +84,7 @@ class AudioFader : public AudioProvider {
   const double playback_rate_;
 
   State state_ = State::kSilent;
-  std::unique_ptr<::media::AudioBus> fade_buffer_;
+  std::unique_ptr<CastAudioBus> fade_buffer_;
   int buffered_frames_ = 0;
   int fade_frames_remaining_ = 0;
 

chromecast/media/audio/cast_audio_bus.cc

+// Copyright 2020 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/audio/cast_audio_bus.h"
+
+#include <cstring>
+
+#include "base/memory/ptr_util.h"
+
+namespace chromecast {
+namespace media {
+
+CastAudioBus::CastAudioBus(int channels, int frames) : frames_(frames) {
+  data_.reset(new float[channels * frames]);
+  channel_data_.reserve(channels);
+  for (int i = 0; i < channels; ++i)
+    channel_data_.push_back(data_.get() + i * frames);
+}
+
+CastAudioBus::~CastAudioBus() = default;
+
+// static
+std::unique_ptr<CastAudioBus> CastAudioBus::Create(int channels, int frames) {
+  return base::WrapUnique(new CastAudioBus(channels, frames));
+}
+
+void CastAudioBus::Zero() {
+  std::fill_n(data_.get(), frames() * channels(), 0);
+}
+
+}  // namespace media
+}  // namespace chromecast

chromecast/media/audio/cast_audio_bus.h

+// Copyright 2020 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 CHROMECAST_MEDIA_AUDIO_CAST_AUDIO_BUS_H_
+#define CHROMECAST_MEDIA_AUDIO_CAST_AUDIO_BUS_H_
+
+#include <memory>
+#include <vector>
+
+namespace chromecast {
+namespace media {
+
+// This class is a simplified version of ::media::AudioBus without any
+// dependency on //media.
+class CastAudioBus {
+ public:
+  // Creates a new CastAudioBus and allocates |channels| of length |frames|.
+  static std::unique_ptr<CastAudioBus> Create(int channels, int frames);
+
+  // Returns a raw pointer to the requested channel.
+  float* channel(int channel) { return channel_data_[channel]; }
+  const float* channel(int channel) const { return channel_data_[channel]; }
+
+  // Returns the number of channels.
+  int channels() const { return static_cast<int>(channel_data_.size()); }
+  // Returns the number of frames.
+  int frames() const { return frames_; }
+
+  // Helper method for zeroing out all channels of audio data.
+  void Zero();
+
+  ~CastAudioBus();
+
+ private:
+  CastAudioBus(int channels, int frames);
+
+  // Contiguous block of channel memory.
+  std::unique_ptr<float[]> data_;
+
+  // One float pointer per channel pointing to a contiguous block of memory for
+  // that channel.
+  std::vector<float*> channel_data_;
+  int frames_;
+};
+
+}  // namespace media
+}  // namespace chromecast
+
+#endif  // CHROMECAST_MEDIA_AUDIO_CAST_AUDIO_BUS_H_

chromecast/media/cma/backend/mixer/BUILD.gn

@@ -72,6 +72,7 @@ cast_source_set("mixer") {
     "//chromecast/base:chromecast_switches",
     "//chromecast/base:thread_health_checker",
     "//chromecast/media/audio:audio_io_thread",
+    "//chromecast/media/audio:interleaved_channel_mixer",
     "//chromecast/media/audio:libcast_external_audio_pipeline_1.0",
     "//chromecast/media/audio:processing",
     "//chromecast/media/audio/mixer_service:common",