content/renderer/media/media_stream_audio_processor.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/renderer/media/media_stream_audio_processor.h"
   6
   7 #include "base/command_line.h"
   8 #include "base/metrics/field_trial.h"
   9 #include "base/metrics/histogram.h"
  10 #include "base/trace_event/trace_event.h"
  11 #include "content/public/common/content_switches.h"
  12 #include "content/renderer/media/media_stream_audio_processor_options.h"
  13 #include "content/renderer/media/rtc_media_constraints.h"
  14 #include "content/renderer/media/webrtc_audio_device_impl.h"
  15 #include "media/audio/audio_parameters.h"
  16 #include "media/base/audio_converter.h"
  17 #include "media/base/audio_fifo.h"
  18 #include "media/base/channel_layout.h"
  19 #include "third_party/WebKit/public/platform/WebMediaConstraints.h"
  20 #include "third_party/libjingle/source/talk/app/webrtc/mediaconstraintsinterface.h"
  21 #include "third_party/webrtc/modules/audio_processing/typing_detection.h"
  22
  23 #if defined(OS_CHROMEOS)
  24 #include "base/sys_info.h"
  25 #endif
  26
  27 namespace content {
  28
  29 namespace {
  30
  31 using webrtc::AudioProcessing;
  32
  33 #if defined(OS_ANDROID)
  34 const int kAudioProcessingSampleRate = 16000;
  35 #else
  36 const int kAudioProcessingSampleRate = 32000;
  37 #endif
  38 const int kAudioProcessingNumberOfChannels = 1;
  39
  40 AudioProcessing::ChannelLayout MapLayout(media::ChannelLayout media_layout) {
  41   switch (media_layout) {
  42     case media::CHANNEL_LAYOUT_MONO:
  43       return AudioProcessing::kMono;
  44     case media::CHANNEL_LAYOUT_STEREO:
  45       return AudioProcessing::kStereo;
  46     case media::CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC:
  47       return AudioProcessing::kStereoAndKeyboard;
  48     default:
  49       NOTREACHED() << "Layout not supported: " << media_layout;
  50       return AudioProcessing::kMono;
  51   }
  52 }
  53
  54 // This is only used for playout data where only max two channels is supported.
  55 AudioProcessing::ChannelLayout ChannelsToLayout(int num_channels) {
  56   switch (num_channels) {
  57     case 1:
  58       return AudioProcessing::kMono;
  59     case 2:
  60       return AudioProcessing::kStereo;
  61     default:
  62       NOTREACHED() << "Channels not supported: " << num_channels;
  63       return AudioProcessing::kMono;
  64   }
  65 }
  66
  67 // Used by UMA histograms and entries shouldn't be re-ordered or removed.
  68 enum AudioTrackProcessingStates {
  69   AUDIO_PROCESSING_ENABLED = 0,
  70   AUDIO_PROCESSING_DISABLED,
  71   AUDIO_PROCESSING_IN_WEBRTC,
  72   AUDIO_PROCESSING_MAX
  73 };
  74
  75 void RecordProcessingState(AudioTrackProcessingStates state) {
  76   UMA_HISTOGRAM_ENUMERATION("Media.AudioTrackProcessingStates",
  77                             state, AUDIO_PROCESSING_MAX);
  78 }
  79
  80 bool isDelayAgnosticAecEnabled() {
  81   // Note: It's important to query the field trial state first, to ensure that
  82   // UMA reports the correct group.
  83   const std::string group_name =
  84       base::FieldTrialList::FindFullName("UseDelayAgnosticAEC");
  85   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
  86   if (command_line->HasSwitch(switches::kEnableDelayAgnosticAec))
  87     return true;
  88
  89   return (group_name == "Enabled" || group_name == "DefaultEnabled");
  90 }
  91 }  // namespace
  92
  93 // Wraps AudioBus to provide access to the array of channel pointers, since this
  94 // is the type webrtc::AudioProcessing deals in. The array is refreshed on every
  95 // channel_ptrs() call, and will be valid until the underlying AudioBus pointers
  96 // are changed, e.g. through calls to SetChannelData() or SwapChannels().
  97 //
  98 // All methods are called on one of the capture or render audio threads
  99 // exclusively.
 100 class MediaStreamAudioBus {
 101  public:
 102   MediaStreamAudioBus(int channels, int frames)
 103       : bus_(media::AudioBus::Create(channels, frames)),
 104         channel_ptrs_(new float*[channels]) {
 105     // May be created in the main render thread and used in the audio threads.
 106     thread_checker_.DetachFromThread();
 107   }
 108
 109   media::AudioBus* bus() {
 110     DCHECK(thread_checker_.CalledOnValidThread());
 111     return bus_.get();
 112   }
 113
 114   float* const* channel_ptrs() {
 115     DCHECK(thread_checker_.CalledOnValidThread());
 116     for (int i = 0; i < bus_->channels(); ++i) {
 117       channel_ptrs_[i] = bus_->channel(i);
 118     }
 119     return channel_ptrs_.get();
 120   }
 121
 122  private:
 123   base::ThreadChecker thread_checker_;
 124   scoped_ptr<media::AudioBus> bus_;
 125   scoped_ptr<float*[]> channel_ptrs_;
 126 };
 127
 128 // Wraps AudioFifo to provide a cleaner interface to MediaStreamAudioProcessor.
 129 // It avoids the FIFO when the source and destination frames match. All methods
 130 // are called on one of the capture or render audio threads exclusively. If
 131 // |source_channels| is larger than |destination_channels|, only the first
 132 // |destination_channels| are kept from the source.
 133 class MediaStreamAudioFifo {
 134  public:
 135   MediaStreamAudioFifo(int source_channels,
 136                        int destination_channels,
 137                        int source_frames,
 138                        int destination_frames,
 139                        int sample_rate)
 140      : source_channels_(source_channels),
 141        source_frames_(source_frames),
 142        sample_rate_(sample_rate),
 143        destination_(
 144            new MediaStreamAudioBus(destination_channels, destination_frames)),
 145        data_available_(false) {
 146     DCHECK_GE(source_channels, destination_channels);
 147     DCHECK_GT(sample_rate_, 0);
 148
 149     if (source_channels > destination_channels) {
 150       audio_source_intermediate_ =
 151           media::AudioBus::CreateWrapper(destination_channels);
 152     }
 153
 154     if (source_frames != destination_frames) {
 155       // Since we require every Push to be followed by as many Consumes as
 156       // possible, twice the larger of the two is a (probably) loose upper bound
 157       // on the FIFO size.
 158       const int fifo_frames = 2 * std::max(source_frames, destination_frames);
 159       fifo_.reset(new media::AudioFifo(destination_channels, fifo_frames));
 160     }
 161
 162     // May be created in the main render thread and used in the audio threads.
 163     thread_checker_.DetachFromThread();
 164   }
 165
 166   void Push(const media::AudioBus& source, base::TimeDelta audio_delay) {
 167     DCHECK(thread_checker_.CalledOnValidThread());
 168     DCHECK_EQ(source.channels(), source_channels_);
 169     DCHECK_EQ(source.frames(), source_frames_);
 170
 171     const media::AudioBus* source_to_push = &source;
 172
 173     if (audio_source_intermediate_) {
 174       for (int i = 0; i < destination_->bus()->channels(); ++i) {
 175         audio_source_intermediate_->SetChannelData(
 176             i,
 177             const_cast<float*>(source.channel(i)));
 178       }
 179       audio_source_intermediate_->set_frames(source.frames());
 180       source_to_push = audio_source_intermediate_.get();
 181     }
 182
 183     if (fifo_) {
 184       next_audio_delay_ = audio_delay +
 185           fifo_->frames() * base::TimeDelta::FromSeconds(1) / sample_rate_;
 186       fifo_->Push(source_to_push);
 187     } else {
 188       source_to_push->CopyTo(destination_->bus());
 189       next_audio_delay_ = audio_delay;
 190       data_available_ = true;
 191     }
 192   }
 193
 194   // Returns true if there are destination_frames() of data available to be
 195   // consumed, and otherwise false.
 196   bool Consume(MediaStreamAudioBus** destination,
 197                base::TimeDelta* audio_delay) {
 198     DCHECK(thread_checker_.CalledOnValidThread());
 199
 200     if (fifo_) {
 201       if (fifo_->frames() < destination_->bus()->frames())
 202         return false;
 203
 204       fifo_->Consume(destination_->bus(), 0, destination_->bus()->frames());
 205       *audio_delay = next_audio_delay_;
 206       next_audio_delay_ -=
 207           destination_->bus()->frames() * base::TimeDelta::FromSeconds(1) /
 208               sample_rate_;
 209     } else {
 210       if (!data_available_)
 211         return false;
 212       *audio_delay = next_audio_delay_;
 213       // The data was already copied to |destination_| in this case.
 214       data_available_ = false;
 215     }
 216
 217     *destination = destination_.get();
 218     return true;
 219   }
 220
 221  private:
 222   base::ThreadChecker thread_checker_;
 223   const int source_channels_;  // For a DCHECK.
 224   const int source_frames_;  // For a DCHECK.
 225   const int sample_rate_;
 226   scoped_ptr<media::AudioBus> audio_source_intermediate_;
 227   scoped_ptr<MediaStreamAudioBus> destination_;
 228   scoped_ptr<media::AudioFifo> fifo_;
 229
 230   // When using |fifo_|, this is the audio delay of the first sample to be
 231   // consumed next from the FIFO.  When not using |fifo_|, this is the audio
 232   // delay of the first sample in |destination_|.
 233   base::TimeDelta next_audio_delay_;
 234
 235   // True when |destination_| contains the data to be returned by the next call
 236   // to Consume().  Only used when the FIFO is disabled.
 237   bool data_available_;
 238 };
 239
 240 MediaStreamAudioProcessor::MediaStreamAudioProcessor(
 241     const blink::WebMediaConstraints& constraints,
 242     int effects,
 243     WebRtcPlayoutDataSource* playout_data_source)
 244     : render_delay_ms_(0),
 245       playout_data_source_(playout_data_source),
 246       audio_mirroring_(false),
 247       typing_detected_(false),
 248       stopped_(false) {
 249   capture_thread_checker_.DetachFromThread();
 250   render_thread_checker_.DetachFromThread();
 251   InitializeAudioProcessingModule(constraints, effects);
 252
 253   aec_dump_message_filter_ = AecDumpMessageFilter::Get();
 254   // In unit tests not creating a message filter, |aec_dump_message_filter_|
 255   // will be NULL. We can just ignore that. Other unit tests and browser tests
 256   // ensure that we do get the filter when we should.
 257   if (aec_dump_message_filter_.get())
 258     aec_dump_message_filter_->AddDelegate(this);
 259 }
 260
 261 MediaStreamAudioProcessor::~MediaStreamAudioProcessor() {
 262   DCHECK(main_thread_checker_.CalledOnValidThread());
 263   Stop();
 264 }
 265
 266 void MediaStreamAudioProcessor::OnCaptureFormatChanged(
 267     const media::AudioParameters& input_format) {
 268   DCHECK(main_thread_checker_.CalledOnValidThread());
 269   // There is no need to hold a lock here since the caller guarantees that
 270   // there is no more PushCaptureData() and ProcessAndConsumeData() callbacks
 271   // on the capture thread.
 272   InitializeCaptureFifo(input_format);
 273
 274   // Reset the |capture_thread_checker_| since the capture data will come from
 275   // a new capture thread.
 276   capture_thread_checker_.DetachFromThread();
 277 }
 278
 279 void MediaStreamAudioProcessor::PushCaptureData(
 280     const media::AudioBus& audio_source,
 281     base::TimeDelta capture_delay) {
 282   DCHECK(capture_thread_checker_.CalledOnValidThread());
 283
 284   capture_fifo_->Push(audio_source, capture_delay);
 285 }
 286
 287 bool MediaStreamAudioProcessor::ProcessAndConsumeData(
 288     int volume,
 289     bool key_pressed,
 290     media::AudioBus** processed_data,
 291     base::TimeDelta* capture_delay,
 292     int* new_volume) {
 293   DCHECK(capture_thread_checker_.CalledOnValidThread());
 294   DCHECK(processed_data);
 295   DCHECK(capture_delay);
 296   DCHECK(new_volume);
 297
 298   TRACE_EVENT0("audio", "MediaStreamAudioProcessor::ProcessAndConsumeData");
 299
 300   MediaStreamAudioBus* process_bus;
 301   if (!capture_fifo_->Consume(&process_bus, capture_delay))
 302     return false;
 303
 304   // Use the process bus directly if audio processing is disabled.
 305   MediaStreamAudioBus* output_bus = process_bus;
 306   *new_volume = 0;
 307   if (audio_processing_) {
 308     output_bus = output_bus_.get();
 309     *new_volume = ProcessData(process_bus->channel_ptrs(),
 310                               process_bus->bus()->frames(), *capture_delay,
 311                               volume, key_pressed, output_bus->channel_ptrs());
 312   }
 313
 314   // Swap channels before interleaving the data.
 315   if (audio_mirroring_ &&
 316       output_format_.channel_layout() == media::CHANNEL_LAYOUT_STEREO) {
 317     // Swap the first and second channels.
 318     output_bus->bus()->SwapChannels(0, 1);
 319   }
 320
 321   *processed_data = output_bus->bus();
 322
 323   return true;
 324 }
 325
 326 void MediaStreamAudioProcessor::Stop() {
 327   DCHECK(main_thread_checker_.CalledOnValidThread());
 328   if (stopped_)
 329     return;
 330
 331   stopped_ = true;
 332
 333   if (aec_dump_message_filter_.get()) {
 334     aec_dump_message_filter_->RemoveDelegate(this);
 335     aec_dump_message_filter_ = NULL;
 336   }
 337
 338   if (!audio_processing_.get())
 339     return;
 340
 341   StopEchoCancellationDump(audio_processing_.get());
 342
 343   if (playout_data_source_) {
 344     playout_data_source_->RemovePlayoutSink(this);
 345     playout_data_source_ = NULL;
 346   }
 347 }
 348
 349 const media::AudioParameters& MediaStreamAudioProcessor::InputFormat() const {
 350   return input_format_;
 351 }
 352
 353 const media::AudioParameters& MediaStreamAudioProcessor::OutputFormat() const {
 354   return output_format_;
 355 }
 356
 357 void MediaStreamAudioProcessor::OnAecDumpFile(
 358     const IPC::PlatformFileForTransit& file_handle) {
 359   DCHECK(main_thread_checker_.CalledOnValidThread());
 360
 361   base::File file = IPC::PlatformFileForTransitToFile(file_handle);
 362   DCHECK(file.IsValid());
 363
 364   if (audio_processing_)
 365     StartEchoCancellationDump(audio_processing_.get(), file.Pass());
 366   else
 367     file.Close();
 368 }
 369
 370 void MediaStreamAudioProcessor::OnDisableAecDump() {
 371   DCHECK(main_thread_checker_.CalledOnValidThread());
 372   if (audio_processing_)
 373     StopEchoCancellationDump(audio_processing_.get());
 374 }
 375
 376 void MediaStreamAudioProcessor::OnIpcClosing() {
 377   DCHECK(main_thread_checker_.CalledOnValidThread());
 378   aec_dump_message_filter_ = NULL;
 379 }
 380
 381 void MediaStreamAudioProcessor::OnPlayoutData(media::AudioBus* audio_bus,
 382                                               int sample_rate,
 383                                               int audio_delay_milliseconds) {
 384   DCHECK(render_thread_checker_.CalledOnValidThread());
 385   DCHECK(audio_processing_->echo_control_mobile()->is_enabled() ^
 386          audio_processing_->echo_cancellation()->is_enabled());
 387
 388   TRACE_EVENT0("audio", "MediaStreamAudioProcessor::OnPlayoutData");
 389   DCHECK_LT(audio_delay_milliseconds,
 390             std::numeric_limits<base::subtle::Atomic32>::max());
 391   base::subtle::Release_Store(&render_delay_ms_, audio_delay_milliseconds);
 392
 393   InitializeRenderFifoIfNeeded(sample_rate, audio_bus->channels(),
 394                                audio_bus->frames());
 395
 396   render_fifo_->Push(
 397       *audio_bus, base::TimeDelta::FromMilliseconds(audio_delay_milliseconds));
 398   MediaStreamAudioBus* analysis_bus;
 399   base::TimeDelta audio_delay;
 400   while (render_fifo_->Consume(&analysis_bus, &audio_delay)) {
 401     // TODO(ajm): Should AnalyzeReverseStream() account for the |audio_delay|?
 402     audio_processing_->AnalyzeReverseStream(
 403         analysis_bus->channel_ptrs(),
 404         analysis_bus->bus()->frames(),
 405         sample_rate,
 406         ChannelsToLayout(audio_bus->channels()));
 407   }
 408 }
 409
 410 void MediaStreamAudioProcessor::OnPlayoutDataSourceChanged() {
 411   DCHECK(main_thread_checker_.CalledOnValidThread());
 412   // There is no need to hold a lock here since the caller guarantees that
 413   // there is no more OnPlayoutData() callback on the render thread.
 414   render_thread_checker_.DetachFromThread();
 415   render_fifo_.reset();
 416 }
 417
 418 void MediaStreamAudioProcessor::GetStats(AudioProcessorStats* stats) {
 419   stats->typing_noise_detected =
 420       (base::subtle::Acquire_Load(&typing_detected_) != false);
 421   GetAecStats(audio_processing_.get(), stats);
 422   if (echo_information_)
 423     echo_information_.get()->UpdateAecDelayStats(stats->echo_delay_median_ms);
 424 }
 425
 426 void MediaStreamAudioProcessor::InitializeAudioProcessingModule(
 427     const blink::WebMediaConstraints& constraints, int effects) {
 428   DCHECK(main_thread_checker_.CalledOnValidThread());
 429   DCHECK(!audio_processing_);
 430
 431   MediaAudioConstraints audio_constraints(constraints, effects);
 432
 433   // Audio mirroring can be enabled even though audio processing is otherwise
 434   // disabled.
 435   audio_mirroring_ = audio_constraints.GetProperty(
 436       MediaAudioConstraints::kGoogAudioMirroring);
 437
 438 #if defined(OS_IOS)
 439   // On iOS, VPIO provides built-in AGC and AEC.
 440   const bool echo_cancellation = false;
 441   const bool goog_agc = false;
 442 #else
 443   const bool echo_cancellation =
 444       audio_constraints.GetEchoCancellationProperty();
 445   const bool goog_agc = audio_constraints.GetProperty(
 446       MediaAudioConstraints::kGoogAutoGainControl);
 447 #endif
 448
 449 #if defined(OS_IOS) || defined(OS_ANDROID)
 450   const bool goog_experimental_aec = false;
 451   const bool goog_typing_detection = false;
 452 #else
 453   const bool goog_experimental_aec = audio_constraints.GetProperty(
 454       MediaAudioConstraints::kGoogExperimentalEchoCancellation);
 455   const bool goog_typing_detection = audio_constraints.GetProperty(
 456       MediaAudioConstraints::kGoogTypingNoiseDetection);
 457 #endif
 458
 459   const bool goog_ns = audio_constraints.GetProperty(
 460       MediaAudioConstraints::kGoogNoiseSuppression);
 461   const bool goog_experimental_ns = audio_constraints.GetProperty(
 462       MediaAudioConstraints::kGoogExperimentalNoiseSuppression);
 463   const bool goog_beamforming = audio_constraints.GetProperty(
 464       MediaAudioConstraints::kGoogBeamforming);
 465  const bool goog_high_pass_filter = audio_constraints.GetProperty(
 466      MediaAudioConstraints::kGoogHighpassFilter);
 467
 468   // Return immediately if no goog constraint is enabled.
 469   if (!echo_cancellation && !goog_experimental_aec && !goog_ns &&
 470       !goog_high_pass_filter && !goog_typing_detection &&
 471       !goog_agc && !goog_experimental_ns && !goog_beamforming) {
 472     RecordProcessingState(AUDIO_PROCESSING_DISABLED);
 473     return;
 474   }
 475
 476   // Experimental options provided at creation.
 477   webrtc::Config config;
 478   if (goog_experimental_aec)
 479     config.Set<webrtc::DelayCorrection>(new webrtc::DelayCorrection(true));
 480   if (goog_experimental_ns)
 481     config.Set<webrtc::ExperimentalNs>(new webrtc::ExperimentalNs(true));
 482   if (isDelayAgnosticAecEnabled())
 483     config.Set<webrtc::ReportedDelay>(new webrtc::ReportedDelay(false));
 484   if (goog_beamforming) {
 485     ConfigureBeamforming(&config);
 486   }
 487
 488   // Create and configure the webrtc::AudioProcessing.
 489   audio_processing_.reset(webrtc::AudioProcessing::Create(config));
 490
 491   // Enable the audio processing components.
 492   if (echo_cancellation) {
 493     EnableEchoCancellation(audio_processing_.get());
 494
 495     if (playout_data_source_)
 496       playout_data_source_->AddPlayoutSink(this);
 497
 498     // Prepare for logging echo information. If there are data remaining in
 499     // |echo_information_| we simply discard it.
 500     echo_information_.reset(new EchoInformation());
 501   }
 502
 503   if (goog_ns)
 504     EnableNoiseSuppression(audio_processing_.get());
 505
 506   if (goog_high_pass_filter)
 507     EnableHighPassFilter(audio_processing_.get());
 508
 509   if (goog_typing_detection) {
 510     // TODO(xians): Remove this |typing_detector_| after the typing suppression
 511     // is enabled by default.
 512     typing_detector_.reset(new webrtc::TypingDetection());
 513     EnableTypingDetection(audio_processing_.get(), typing_detector_.get());
 514   }
 515
 516   if (goog_agc)
 517     EnableAutomaticGainControl(audio_processing_.get());
 518
 519   RecordProcessingState(AUDIO_PROCESSING_ENABLED);
 520 }
 521
 522 void MediaStreamAudioProcessor::ConfigureBeamforming(webrtc::Config* config) {
 523   bool enabled = false;
 524   std::vector<webrtc::Point> geometry(1, webrtc::Point(0.f, 0.f, 0.f));
 525 #if defined(OS_CHROMEOS)
 526   const std::string board = base::SysInfo::GetLsbReleaseBoard();
 527   if (board == "peach_pi") {
 528     enabled = true;
 529     geometry.push_back(webrtc::Point(0.050f, 0.f, 0.f));
 530   } else if (board == "swanky") {
 531     enabled = true;
 532     geometry.push_back(webrtc::Point(0.052f, 0.f, 0.f));
 533   }
 534 #endif
 535   config->Set<webrtc::Beamforming>(new webrtc::Beamforming(enabled, geometry));
 536 }
 537
 538 void MediaStreamAudioProcessor::InitializeCaptureFifo(
 539     const media::AudioParameters& input_format) {
 540   DCHECK(main_thread_checker_.CalledOnValidThread());
 541   DCHECK(input_format.IsValid());
 542   input_format_ = input_format;
 543
 544   // TODO(ajm): For now, we assume fixed parameters for the output when audio
 545   // processing is enabled, to match the previous behavior. We should either
 546   // use the input parameters (in which case, audio processing will convert
 547   // at output) or ideally, have a backchannel from the sink to know what
 548   // format it would prefer.
 549   const int output_sample_rate = audio_processing_ ?
 550       kAudioProcessingSampleRate : input_format.sample_rate();
 551   media::ChannelLayout output_channel_layout = audio_processing_ ?
 552       media::GuessChannelLayout(kAudioProcessingNumberOfChannels) :
 553       input_format.channel_layout();
 554
 555   // The output channels from the fifo is normally the same as input.
 556   int fifo_output_channels = input_format.channels();
 557
 558   // Special case for if we have a keyboard mic channel on the input and no
 559   // audio processing is used. We will then have the fifo strip away that
 560   // channel. So we use stereo as output layout, and also change the output
 561   // channels for the fifo.
 562   if (input_format.channel_layout() ==
 563           media::CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC &&
 564       !audio_processing_) {
 565     output_channel_layout = media::CHANNEL_LAYOUT_STEREO;
 566     fifo_output_channels = ChannelLayoutToChannelCount(output_channel_layout);
 567   }
 568
 569   // webrtc::AudioProcessing requires a 10 ms chunk size. We use this native
 570   // size when processing is enabled. When disabled we use the same size as
 571   // the source if less than 10 ms.
 572   //
 573   // TODO(ajm): This conditional buffer size appears to be assuming knowledge of
 574   // the sink based on the source parameters. PeerConnection sinks seem to want
 575   // 10 ms chunks regardless, while WebAudio sinks want less, and we're assuming
 576   // we can identify WebAudio sinks by the input chunk size. Less fragile would
 577   // be to have the sink actually tell us how much it wants (as in the above
 578   // TODO).
 579   int processing_frames = input_format.sample_rate() / 100;
 580   int output_frames = output_sample_rate / 100;
 581   if (!audio_processing_ && input_format.frames_per_buffer() < output_frames) {
 582     processing_frames = input_format.frames_per_buffer();
 583     output_frames = processing_frames;
 584   }
 585
 586   output_format_ = media::AudioParameters(
 587       media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
 588       output_channel_layout,
 589       output_sample_rate,
 590       16,
 591       output_frames);
 592
 593   capture_fifo_.reset(
 594       new MediaStreamAudioFifo(input_format.channels(),
 595                                fifo_output_channels,
 596                                input_format.frames_per_buffer(),
 597                                processing_frames,
 598                                input_format.sample_rate()));
 599
 600   if (audio_processing_) {
 601     output_bus_.reset(new MediaStreamAudioBus(output_format_.channels(),
 602                                               output_frames));
 603   }
 604 }
 605
 606 void MediaStreamAudioProcessor::InitializeRenderFifoIfNeeded(
 607     int sample_rate, int number_of_channels, int frames_per_buffer) {
 608   DCHECK(render_thread_checker_.CalledOnValidThread());
 609   if (render_fifo_.get() &&
 610       render_format_.sample_rate() == sample_rate &&
 611       render_format_.channels() == number_of_channels &&
 612       render_format_.frames_per_buffer() == frames_per_buffer) {
 613     // Do nothing if the |render_fifo_| has been setup properly.
 614     return;
 615   }
 616
 617   render_format_ = media::AudioParameters(
 618       media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
 619       media::GuessChannelLayout(number_of_channels),
 620       sample_rate,
 621       16,
 622       frames_per_buffer);
 623
 624   const int analysis_frames = sample_rate / 100;  // 10 ms chunks.
 625   render_fifo_.reset(
 626       new MediaStreamAudioFifo(number_of_channels,
 627                                number_of_channels,
 628                                frames_per_buffer,
 629                                analysis_frames,
 630                                sample_rate));
 631 }
 632
 633 int MediaStreamAudioProcessor::ProcessData(const float* const* process_ptrs,
 634                                            int process_frames,
 635                                            base::TimeDelta capture_delay,
 636                                            int volume,
 637                                            bool key_pressed,
 638                                            float* const* output_ptrs) {
 639   DCHECK(audio_processing_);
 640   DCHECK(capture_thread_checker_.CalledOnValidThread());
 641
 642   TRACE_EVENT0("audio", "MediaStreamAudioProcessor::ProcessData");
 643
 644   base::subtle::Atomic32 render_delay_ms =
 645       base::subtle::Acquire_Load(&render_delay_ms_);
 646   int64 capture_delay_ms = capture_delay.InMilliseconds();
 647   DCHECK_LT(capture_delay_ms,
 648             std::numeric_limits<base::subtle::Atomic32>::max());
 649   int total_delay_ms =  capture_delay_ms + render_delay_ms;
 650   if (total_delay_ms > 300) {
 651     LOG(WARNING) << "Large audio delay, capture delay: " << capture_delay_ms
 652                  << "ms; render delay: " << render_delay_ms << "ms";
 653   }
 654
 655   webrtc::AudioProcessing* ap = audio_processing_.get();
 656   ap->set_stream_delay_ms(total_delay_ms);
 657
 658   DCHECK_LE(volume, WebRtcAudioDeviceImpl::kMaxVolumeLevel);
 659   webrtc::GainControl* agc = ap->gain_control();
 660   int err = agc->set_stream_analog_level(volume);
 661   DCHECK_EQ(err, 0) << "set_stream_analog_level() error: " << err;
 662
 663   ap->set_stream_key_pressed(key_pressed);
 664
 665   err = ap->ProcessStream(process_ptrs,
 666                           process_frames,
 667                           input_format_.sample_rate(),
 668                           MapLayout(input_format_.channel_layout()),
 669                           output_format_.sample_rate(),
 670                           MapLayout(output_format_.channel_layout()),
 671                           output_ptrs);
 672   DCHECK_EQ(err, 0) << "ProcessStream() error: " << err;
 673
 674   if (typing_detector_) {
 675     webrtc::VoiceDetection* vad = ap->voice_detection();
 676     DCHECK(vad->is_enabled());
 677     bool detected = typing_detector_->Process(key_pressed,
 678                                               vad->stream_has_voice());
 679     base::subtle::Release_Store(&typing_detected_, detected);
 680   }
 681
 682   // Return 0 if the volume hasn't been changed, and otherwise the new volume.
 683   return (agc->stream_analog_level() == volume) ?
 684       0 : agc->stream_analog_level();
 685 }
 686
 687 }  // namespace content