media/audio/audio_input_controller.cc

   1 // Copyright (c) 2012 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 "media/audio/audio_input_controller.h"
   6
   7 #include "base/bind.h"
   8 #include "base/metrics/histogram_macros.h"
   9 #include "base/strings/string_number_conversions.h"
  10 #include "base/strings/stringprintf.h"
  11 #include "base/threading/thread_restrictions.h"
  12 #include "base/time/time.h"
  13 #include "media/audio/audio_parameters.h"
  14 #include "media/base/user_input_monitor.h"
  15
  16 using base::TimeDelta;
  17
  18 namespace {
  19
  20 const int kMaxInputChannels = 3;
  21
  22 // TODO(henrika): remove usage of timers and add support for proper
  23 // notification of when the input device is removed.  This was originally added
  24 // to resolve http://crbug.com/79936 for Windows platforms.  This then caused
  25 // breakage (very hard to repro bugs!) on other platforms: See
  26 // http://crbug.com/226327 and http://crbug.com/230972.
  27 // See also that the timer has been disabled on Mac now due to
  28 // crbug.com/357501.
  29 const int kTimerResetIntervalSeconds = 1;
  30 // We have received reports that the timer can be too trigger happy on some
  31 // Mac devices and the initial timer interval has therefore been increased
  32 // from 1 second to 5 seconds.
  33 const int kTimerInitialIntervalSeconds = 5;
  34
  35 #if defined(AUDIO_POWER_MONITORING)
  36 // Time in seconds between two successive measurements of audio power levels.
  37 const int kPowerMonitorLogIntervalSeconds = 15;
  38
  39 // A warning will be logged when the microphone audio volume is below this
  40 // threshold.
  41 const int kLowLevelMicrophoneLevelPercent = 10;
  42
  43 // Logs if the user has enabled the microphone mute or not. This is normally
  44 // done by marking a checkbox in an audio-settings UI which is unique for each
  45 // platform. Elements in this enum should not be added, deleted or rearranged.
  46 enum MicrophoneMuteResult {
  47   MICROPHONE_IS_MUTED = 0,
  48   MICROPHONE_IS_NOT_MUTED = 1,
  49   MICROPHONE_MUTE_MAX = MICROPHONE_IS_NOT_MUTED
  50 };
  51
  52 void LogMicrophoneMuteResult(MicrophoneMuteResult result) {
  53   UMA_HISTOGRAM_ENUMERATION("Media.MicrophoneMuted",
  54                             result,
  55                             MICROPHONE_MUTE_MAX + 1);
  56 }
  57
  58 // Helper method which calculates the average power of an audio bus. Unit is in
  59 // dBFS, where 0 dBFS corresponds to all channels and samples equal to 1.0.
  60 float AveragePower(const media::AudioBus& buffer) {
  61   const int frames = buffer.frames();
  62   const int channels = buffer.channels();
  63   if (frames <= 0 || channels <= 0)
  64     return 0.0f;
  65
  66   // Scan all channels and accumulate the sum of squares for all samples.
  67   float sum_power = 0.0f;
  68   for (int ch = 0; ch < channels; ++ch) {
  69     const float* channel_data = buffer.channel(ch);
  70     for (int i = 0; i < frames; i++) {
  71       const float sample = channel_data[i];
  72       sum_power += sample * sample;
  73     }
  74   }
  75
  76   // Update accumulated average results, with clamping for sanity.
  77   const float average_power =
  78       std::max(0.0f, std::min(1.0f, sum_power / (frames * channels)));
  79
  80   // Convert average power level to dBFS units, and pin it down to zero if it
  81   // is insignificantly small.
  82   const float kInsignificantPower = 1.0e-10f;  // -100 dBFS
  83   const float power_dbfs = average_power < kInsignificantPower ?
  84       -std::numeric_limits<float>::infinity() : 10.0f * log10f(average_power);
  85
  86   return power_dbfs;
  87 }
  88 #endif  // AUDIO_POWER_MONITORING
  89
  90 }
  91
  92 // Used to log the result of capture startup.
  93 // This was previously logged as a boolean with only the no callback and OK
  94 // options. The enum order is kept to ensure backwards compatibility.
  95 // Elements in this enum should not be deleted or rearranged; the only
  96 // permitted operation is to add new elements before CAPTURE_STARTUP_RESULT_MAX
  97 // and update CAPTURE_STARTUP_RESULT_MAX.
  98 enum CaptureStartupResult {
  99   CAPTURE_STARTUP_NO_DATA_CALLBACK = 0,
 100   CAPTURE_STARTUP_OK = 1,
 101   CAPTURE_STARTUP_CREATE_STREAM_FAILED = 2,
 102   CAPTURE_STARTUP_OPEN_STREAM_FAILED = 3,
 103   CAPTURE_STARTUP_RESULT_MAX = CAPTURE_STARTUP_OPEN_STREAM_FAILED
 104 };
 105
 106 void LogCaptureStartupResult(CaptureStartupResult result) {
 107   UMA_HISTOGRAM_ENUMERATION("Media.AudioInputControllerCaptureStartupSuccess",
 108                             result,
 109                             CAPTURE_STARTUP_RESULT_MAX + 1);
 110
 111 }
 112
 113 namespace media {
 114
 115 // static
 116 AudioInputController::Factory* AudioInputController::factory_ = NULL;
 117
 118 AudioInputController::AudioInputController(EventHandler* handler,
 119                                            SyncWriter* sync_writer,
 120                                            UserInputMonitor* user_input_monitor,
 121                                            const bool agc_is_enabled)
 122     : creator_task_runner_(base::MessageLoopProxy::current()),
 123       handler_(handler),
 124       stream_(NULL),
 125       data_is_active_(false),
 126       state_(CLOSED),
 127       sync_writer_(sync_writer),
 128       max_volume_(0.0),
 129       user_input_monitor_(user_input_monitor),
 130       agc_is_enabled_(agc_is_enabled),
 131 #if defined(AUDIO_POWER_MONITORING)
 132       power_measurement_is_enabled_(false),
 133       log_silence_state_(false),
 134       silence_state_(SILENCE_STATE_NO_MEASUREMENT),
 135 #endif
 136       prev_key_down_count_(0) {
 137   DCHECK(creator_task_runner_.get());
 138 }
 139
 140 AudioInputController::~AudioInputController() {
 141   DCHECK_EQ(state_, CLOSED);
 142 }
 143
 144 // static
 145 scoped_refptr<AudioInputController> AudioInputController::Create(
 146     AudioManager* audio_manager,
 147     EventHandler* event_handler,
 148     const AudioParameters& params,
 149     const std::string& device_id,
 150     UserInputMonitor* user_input_monitor) {
 151   DCHECK(audio_manager);
 152
 153   if (!params.IsValid() || (params.channels() > kMaxInputChannels))
 154     return NULL;
 155
 156   if (factory_) {
 157     return factory_->Create(
 158         audio_manager, event_handler, params, user_input_monitor);
 159   }
 160   scoped_refptr<AudioInputController> controller(
 161       new AudioInputController(event_handler, NULL, user_input_monitor, false));
 162
 163   controller->task_runner_ = audio_manager->GetTaskRunner();
 164
 165   // Create and open a new audio input stream from the existing
 166   // audio-device thread.
 167   if (!controller->task_runner_->PostTask(
 168           FROM_HERE,
 169           base::Bind(&AudioInputController::DoCreate,
 170                      controller,
 171                      base::Unretained(audio_manager),
 172                      params,
 173                      device_id))) {
 174     controller = NULL;
 175   }
 176
 177   return controller;
 178 }
 179
 180 // static
 181 scoped_refptr<AudioInputController> AudioInputController::CreateLowLatency(
 182     AudioManager* audio_manager,
 183     EventHandler* event_handler,
 184     const AudioParameters& params,
 185     const std::string& device_id,
 186     SyncWriter* sync_writer,
 187     UserInputMonitor* user_input_monitor,
 188     const bool agc_is_enabled) {
 189   DCHECK(audio_manager);
 190   DCHECK(sync_writer);
 191
 192   if (!params.IsValid() || (params.channels() > kMaxInputChannels))
 193     return NULL;
 194
 195   // Create the AudioInputController object and ensure that it runs on
 196   // the audio-manager thread.
 197   scoped_refptr<AudioInputController> controller(new AudioInputController(
 198       event_handler, sync_writer, user_input_monitor, agc_is_enabled));
 199   controller->task_runner_ = audio_manager->GetTaskRunner();
 200
 201   // Create and open a new audio input stream from the existing
 202   // audio-device thread. Use the provided audio-input device.
 203   if (!controller->task_runner_->PostTask(
 204           FROM_HERE,
 205           base::Bind(&AudioInputController::DoCreateForLowLatency,
 206                      controller,
 207                      base::Unretained(audio_manager),
 208                      params,
 209                      device_id))) {
 210     controller = NULL;
 211   }
 212
 213   return controller;
 214 }
 215
 216 // static
 217 scoped_refptr<AudioInputController> AudioInputController::CreateForStream(
 218     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
 219     EventHandler* event_handler,
 220     AudioInputStream* stream,
 221     SyncWriter* sync_writer,
 222     UserInputMonitor* user_input_monitor) {
 223   DCHECK(sync_writer);
 224   DCHECK(stream);
 225
 226   // Create the AudioInputController object and ensure that it runs on
 227   // the audio-manager thread.
 228   scoped_refptr<AudioInputController> controller(new AudioInputController(
 229       event_handler, sync_writer, user_input_monitor, false));
 230   controller->task_runner_ = task_runner;
 231
 232   // TODO(miu): See TODO at top of file.  Until that's resolved, we need to
 233   // disable the error auto-detection here (since the audio mirroring
 234   // implementation will reliably report error and close events).  Note, of
 235   // course, that we're assuming CreateForStream() has been called for the audio
 236   // mirroring use case only.
 237   if (!controller->task_runner_->PostTask(
 238           FROM_HERE,
 239           base::Bind(&AudioInputController::DoCreateForStream,
 240                      controller,
 241                      stream))) {
 242     controller = NULL;
 243   }
 244
 245   return controller;
 246 }
 247
 248 void AudioInputController::Record() {
 249   task_runner_->PostTask(FROM_HERE, base::Bind(
 250       &AudioInputController::DoRecord, this));
 251 }
 252
 253 void AudioInputController::Close(const base::Closure& closed_task) {
 254   DCHECK(!closed_task.is_null());
 255   DCHECK(creator_task_runner_->BelongsToCurrentThread());
 256
 257   task_runner_->PostTaskAndReply(
 258       FROM_HERE, base::Bind(&AudioInputController::DoClose, this), closed_task);
 259 }
 260
 261 void AudioInputController::SetVolume(double volume) {
 262   task_runner_->PostTask(FROM_HERE, base::Bind(
 263       &AudioInputController::DoSetVolume, this, volume));
 264 }
 265
 266 void AudioInputController::DoCreate(AudioManager* audio_manager,
 267                                     const AudioParameters& params,
 268                                     const std::string& device_id) {
 269   DCHECK(task_runner_->BelongsToCurrentThread());
 270   SCOPED_UMA_HISTOGRAM_TIMER("Media.AudioInputController.CreateTime");
 271   if (handler_)
 272     handler_->OnLog(this, "AIC::DoCreate");
 273
 274 #if defined(AUDIO_POWER_MONITORING)
 275   // Disable power monitoring for streams that run without AGC enabled to
 276   // avoid adding logs and UMA for non-WebRTC clients.
 277   power_measurement_is_enabled_ = agc_is_enabled_;
 278   last_audio_level_log_time_ = base::TimeTicks::Now();
 279   silence_state_ = SILENCE_STATE_NO_MEASUREMENT;
 280 #endif
 281
 282   // TODO(miu): See TODO at top of file.  Until that's resolved, assume all
 283   // platform audio input requires the |no_data_timer_| be used to auto-detect
 284   // errors.  In reality, probably only Windows needs to be treated as
 285   // unreliable here.
 286   DoCreateForStream(audio_manager->MakeAudioInputStream(params, device_id));
 287 }
 288
 289 void AudioInputController::DoCreateForLowLatency(AudioManager* audio_manager,
 290                                                  const AudioParameters& params,
 291                                                  const std::string& device_id) {
 292   DCHECK(task_runner_->BelongsToCurrentThread());
 293
 294 #if defined(AUDIO_POWER_MONITORING)
 295   // We only log silence state UMA stats for low latency mode and if we use a
 296   // real device.
 297   if (params.format() != AudioParameters::AUDIO_FAKE)
 298     log_silence_state_ = true;
 299 #endif
 300
 301   low_latency_create_time_ = base::TimeTicks::Now();
 302   DoCreate(audio_manager, params, device_id);
 303 }
 304
 305 void AudioInputController::DoCreateForStream(
 306     AudioInputStream* stream_to_control) {
 307   DCHECK(task_runner_->BelongsToCurrentThread());
 308
 309   DCHECK(!stream_);
 310   stream_ = stream_to_control;
 311
 312   if (!stream_) {
 313     if (handler_)
 314       handler_->OnError(this, STREAM_CREATE_ERROR);
 315     LogCaptureStartupResult(CAPTURE_STARTUP_CREATE_STREAM_FAILED);
 316     return;
 317   }
 318
 319   if (stream_ && !stream_->Open()) {
 320     stream_->Close();
 321     stream_ = NULL;
 322     if (handler_)
 323       handler_->OnError(this, STREAM_OPEN_ERROR);
 324     LogCaptureStartupResult(CAPTURE_STARTUP_OPEN_STREAM_FAILED);
 325     return;
 326   }
 327
 328   DCHECK(!no_data_timer_.get());
 329
 330   // Set AGC state using mode in |agc_is_enabled_| which can only be enabled in
 331   // CreateLowLatency().
 332 #if defined(AUDIO_POWER_MONITORING)
 333   bool agc_is_supported = false;
 334   agc_is_supported = stream_->SetAutomaticGainControl(agc_is_enabled_);
 335   // Disable power measurements on platforms that does not support AGC at a
 336   // lower level. AGC can fail on platforms where we don't support the
 337   // functionality to modify the input volume slider. One such example is
 338   // Windows XP.
 339   power_measurement_is_enabled_ &= agc_is_supported;
 340 #else
 341   stream_->SetAutomaticGainControl(agc_is_enabled_);
 342 #endif
 343
 344   // Create the data timer which will call FirstCheckForNoData(). The timer
 345   // is started in DoRecord() and restarted in each DoCheckForNoData()
 346   // callback.
 347   // The timer is enabled for logging purposes. The NO_DATA_ERROR triggered
 348   // from the timer must be ignored by the EventHandler.
 349   // TODO(henrika): remove usage of timer when it has been verified on Canary
 350   // that we are safe doing so. Goal is to get rid of |no_data_timer_| and
 351   // everything that is tied to it. crbug.com/357569.
 352   no_data_timer_.reset(new base::Timer(
 353       FROM_HERE, base::TimeDelta::FromSeconds(kTimerInitialIntervalSeconds),
 354       base::Bind(&AudioInputController::FirstCheckForNoData,
 355                  base::Unretained(this)), false));
 356
 357   state_ = CREATED;
 358   if (handler_)
 359     handler_->OnCreated(this);
 360
 361   if (user_input_monitor_) {
 362     user_input_monitor_->EnableKeyPressMonitoring();
 363     prev_key_down_count_ = user_input_monitor_->GetKeyPressCount();
 364   }
 365 }
 366
 367 void AudioInputController::DoRecord() {
 368   DCHECK(task_runner_->BelongsToCurrentThread());
 369   SCOPED_UMA_HISTOGRAM_TIMER("Media.AudioInputController.RecordTime");
 370
 371   if (state_ != CREATED)
 372     return;
 373
 374   {
 375     base::AutoLock auto_lock(lock_);
 376     state_ = RECORDING;
 377   }
 378
 379   if (handler_)
 380     handler_->OnLog(this, "AIC::DoRecord");
 381
 382   if (no_data_timer_) {
 383     // Start the data timer. Once |kTimerResetIntervalSeconds| have passed,
 384     // a callback to FirstCheckForNoData() is made.
 385     no_data_timer_->Reset();
 386   }
 387
 388   stream_->Start(this);
 389   if (handler_)
 390     handler_->OnRecording(this);
 391 }
 392
 393 void AudioInputController::DoClose() {
 394   DCHECK(task_runner_->BelongsToCurrentThread());
 395   SCOPED_UMA_HISTOGRAM_TIMER("Media.AudioInputController.CloseTime");
 396
 397   if (state_ == CLOSED)
 398     return;
 399
 400   // If this is a low-latency stream, log the total duration (since DoCreate)
 401   // and add it to a UMA histogram.
 402   if (!low_latency_create_time_.is_null()) {
 403     base::TimeDelta duration =
 404         base::TimeTicks::Now() - low_latency_create_time_;
 405     UMA_HISTOGRAM_LONG_TIMES("Media.InputStreamDuration", duration);
 406     if (handler_) {
 407       std::string log_string =
 408           base::StringPrintf("AIC::DoClose: stream duration=");
 409       log_string += base::Int64ToString(duration.InSeconds());
 410       log_string += " seconds";
 411       handler_->OnLog(this, log_string);
 412     }
 413   }
 414
 415   // Delete the timer on the same thread that created it.
 416   no_data_timer_.reset();
 417
 418   DoStopCloseAndClearStream();
 419   SetDataIsActive(false);
 420
 421   if (SharedMemoryAndSyncSocketMode())
 422     sync_writer_->Close();
 423
 424   if (user_input_monitor_)
 425     user_input_monitor_->DisableKeyPressMonitoring();
 426
 427 #if defined(AUDIO_POWER_MONITORING)
 428   // Send UMA stats if enabled.
 429   if (log_silence_state_)
 430     LogSilenceState(silence_state_);
 431   log_silence_state_ = false;
 432 #endif
 433
 434   state_ = CLOSED;
 435 }
 436
 437 void AudioInputController::DoReportError() {
 438   DCHECK(task_runner_->BelongsToCurrentThread());
 439   if (handler_)
 440     handler_->OnError(this, STREAM_ERROR);
 441 }
 442
 443 void AudioInputController::DoSetVolume(double volume) {
 444   DCHECK(task_runner_->BelongsToCurrentThread());
 445   DCHECK_GE(volume, 0);
 446   DCHECK_LE(volume, 1.0);
 447
 448   if (state_ != CREATED && state_ != RECORDING)
 449     return;
 450
 451   // Only ask for the maximum volume at first call and use cached value
 452   // for remaining function calls.
 453   if (!max_volume_) {
 454     max_volume_ = stream_->GetMaxVolume();
 455   }
 456
 457   if (max_volume_ == 0.0) {
 458     DLOG(WARNING) << "Failed to access input volume control";
 459     return;
 460   }
 461
 462   // Set the stream volume and scale to a range matched to the platform.
 463   stream_->SetVolume(max_volume_ * volume);
 464 }
 465
 466 void AudioInputController::FirstCheckForNoData() {
 467   DCHECK(task_runner_->BelongsToCurrentThread());
 468   LogCaptureStartupResult(GetDataIsActive() ?
 469                           CAPTURE_STARTUP_OK :
 470                           CAPTURE_STARTUP_NO_DATA_CALLBACK);
 471   if (handler_) {
 472     handler_->OnLog(this, GetDataIsActive() ?
 473                     "AIC::FirstCheckForNoData => data is active" :
 474                     "AIC::FirstCheckForNoData => data is NOT active");
 475   }
 476   DoCheckForNoData();
 477 }
 478
 479 void AudioInputController::DoCheckForNoData() {
 480   DCHECK(task_runner_->BelongsToCurrentThread());
 481
 482   if (!GetDataIsActive()) {
 483     // The data-is-active marker will be false only if it has been more than
 484     // one second since a data packet was recorded. This can happen if a
 485     // capture device has been removed or disabled.
 486     if (handler_)
 487       handler_->OnError(this, NO_DATA_ERROR);
 488   }
 489
 490   // Mark data as non-active. The flag will be re-enabled in OnData() each
 491   // time a data packet is received. Hence, under normal conditions, the
 492   // flag will only be disabled during a very short period.
 493   SetDataIsActive(false);
 494
 495   // Restart the timer to ensure that we check the flag again in
 496   // |kTimerResetIntervalSeconds|.
 497   no_data_timer_->Start(
 498       FROM_HERE, base::TimeDelta::FromSeconds(kTimerResetIntervalSeconds),
 499       base::Bind(&AudioInputController::DoCheckForNoData,
 500       base::Unretained(this)));
 501 }
 502
 503 void AudioInputController::OnData(AudioInputStream* stream,
 504                                   const AudioBus* source,
 505                                   uint32 hardware_delay_bytes,
 506                                   double volume) {
 507   // Mark data as active to ensure that the periodic calls to
 508   // DoCheckForNoData() does not report an error to the event handler.
 509   SetDataIsActive(true);
 510
 511   {
 512     base::AutoLock auto_lock(lock_);
 513     if (state_ != RECORDING)
 514       return;
 515   }
 516
 517   bool key_pressed = false;
 518   if (user_input_monitor_) {
 519     size_t current_count = user_input_monitor_->GetKeyPressCount();
 520     key_pressed = current_count != prev_key_down_count_;
 521     prev_key_down_count_ = current_count;
 522     DVLOG_IF(6, key_pressed) << "Detected keypress.";
 523   }
 524
 525   // Use SharedMemory and SyncSocket if the client has created a SyncWriter.
 526   // Used by all low-latency clients except WebSpeech.
 527   if (SharedMemoryAndSyncSocketMode()) {
 528     sync_writer_->Write(source, volume, key_pressed);
 529     sync_writer_->UpdateRecordedBytes(hardware_delay_bytes);
 530
 531 #if defined(AUDIO_POWER_MONITORING)
 532     // Only do power-level measurements if DoCreate() has been called. It will
 533     // ensure that logging will mainly be done for WebRTC and WebSpeech
 534     // clients.
 535     if (!power_measurement_is_enabled_)
 536       return;
 537
 538     // Perform periodic audio (power) level measurements.
 539     if ((base::TimeTicks::Now() - last_audio_level_log_time_).InSeconds() >
 540         kPowerMonitorLogIntervalSeconds) {
 541       // Calculate the average power of the signal, or the energy per sample.
 542       const float average_power_dbfs = AveragePower(*source);
 543
 544       // Add current microphone volume to log and UMA histogram.
 545       const int mic_volume_percent = static_cast<int>(100.0 * volume);
 546
 547       // Use event handler on the audio thread to relay a message to the ARIH
 548       // in content which does the actual logging on the IO thread.
 549       task_runner_->PostTask(FROM_HERE,
 550                              base::Bind(&AudioInputController::DoLogAudioLevels,
 551                                         this,
 552                                         average_power_dbfs,
 553                                         mic_volume_percent));
 554
 555       last_audio_level_log_time_ = base::TimeTicks::Now();
 556     }
 557 #endif
 558     return;
 559   }
 560
 561   // TODO(henrika): Investigate if we can avoid the extra copy here.
 562   // (see http://crbug.com/249316 for details). AFAIK, this scope is only
 563   // active for WebSpeech clients.
 564   scoped_ptr<AudioBus> audio_data =
 565       AudioBus::Create(source->channels(), source->frames());
 566   source->CopyTo(audio_data.get());
 567
 568   // Ownership of the audio buffer will be with the callback until it is run,
 569   // when ownership is passed to the callback function.
 570   task_runner_->PostTask(
 571       FROM_HERE,
 572       base::Bind(
 573           &AudioInputController::DoOnData, this, base::Passed(&audio_data)));
 574 }
 575
 576 void AudioInputController::DoOnData(scoped_ptr<AudioBus> data) {
 577   DCHECK(task_runner_->BelongsToCurrentThread());
 578   if (handler_)
 579     handler_->OnData(this, data.get());
 580 }
 581
 582 void AudioInputController::DoLogAudioLevels(float level_dbfs,
 583                                             int microphone_volume_percent) {
 584 #if defined(AUDIO_POWER_MONITORING)
 585   DCHECK(task_runner_->BelongsToCurrentThread());
 586   if (!handler_)
 587     return;
 588
 589   // Detect if the user has enabled hardware mute by pressing the mute
 590   // button in audio settings for the selected microphone.
 591   const bool microphone_is_muted = stream_->IsMuted();
 592   if (microphone_is_muted) {
 593     LogMicrophoneMuteResult(MICROPHONE_IS_MUTED);
 594     handler_->OnLog(this, "AIC::OnData: microphone is muted!");
 595     // Return early if microphone is muted. No need to adding logs and UMA stats
 596     // of audio levels if we know that the micropone is muted.
 597     return;
 598   }
 599
 600   LogMicrophoneMuteResult(MICROPHONE_IS_NOT_MUTED);
 601
 602   std::string log_string = base::StringPrintf(
 603       "AIC::OnData: average audio level=%.2f dBFS", level_dbfs);
 604   static const float kSilenceThresholdDBFS = -72.24719896f;
 605   if (level_dbfs < kSilenceThresholdDBFS)
 606     log_string += " <=> low audio input level!";
 607   handler_->OnLog(this, log_string);
 608
 609   UpdateSilenceState(level_dbfs < kSilenceThresholdDBFS);
 610
 611   UMA_HISTOGRAM_PERCENTAGE("Media.MicrophoneVolume", microphone_volume_percent);
 612   log_string = base::StringPrintf(
 613       "AIC::OnData: microphone volume=%d%%", microphone_volume_percent);
 614   if (microphone_volume_percent < kLowLevelMicrophoneLevelPercent)
 615     log_string += " <=> low microphone level!";
 616   handler_->OnLog(this, log_string);
 617 #endif
 618 }
 619
 620 void AudioInputController::OnError(AudioInputStream* stream) {
 621   // Handle error on the audio-manager thread.
 622   task_runner_->PostTask(FROM_HERE, base::Bind(
 623       &AudioInputController::DoReportError, this));
 624 }
 625
 626 void AudioInputController::DoStopCloseAndClearStream() {
 627   DCHECK(task_runner_->BelongsToCurrentThread());
 628
 629   // Allow calling unconditionally and bail if we don't have a stream to close.
 630   if (stream_ != NULL) {
 631     stream_->Stop();
 632     stream_->Close();
 633     stream_ = NULL;
 634   }
 635
 636   // The event handler should not be touched after the stream has been closed.
 637   handler_ = NULL;
 638 }
 639
 640 void AudioInputController::SetDataIsActive(bool enabled) {
 641   base::subtle::Release_Store(&data_is_active_, enabled);
 642 }
 643
 644 bool AudioInputController::GetDataIsActive() {
 645   return (base::subtle::Acquire_Load(&data_is_active_) != false);
 646 }
 647
 648 #if defined(AUDIO_POWER_MONITORING)
 649 void AudioInputController::UpdateSilenceState(bool silence) {
 650   if (silence) {
 651     if (silence_state_ == SILENCE_STATE_NO_MEASUREMENT) {
 652       silence_state_ = SILENCE_STATE_ONLY_SILENCE;
 653     } else if (silence_state_ == SILENCE_STATE_ONLY_AUDIO) {
 654       silence_state_ = SILENCE_STATE_AUDIO_AND_SILENCE;
 655     } else {
 656       DCHECK(silence_state_ == SILENCE_STATE_ONLY_SILENCE ||
 657              silence_state_ == SILENCE_STATE_AUDIO_AND_SILENCE);
 658     }
 659   } else {
 660     if (silence_state_ == SILENCE_STATE_NO_MEASUREMENT) {
 661       silence_state_ = SILENCE_STATE_ONLY_AUDIO;
 662     } else if (silence_state_ == SILENCE_STATE_ONLY_SILENCE) {
 663       silence_state_ = SILENCE_STATE_AUDIO_AND_SILENCE;
 664     } else {
 665       DCHECK(silence_state_ == SILENCE_STATE_ONLY_AUDIO ||
 666              silence_state_ == SILENCE_STATE_AUDIO_AND_SILENCE);
 667     }
 668   }
 669 }
 670
 671 void AudioInputController::LogSilenceState(SilenceState value) {
 672   UMA_HISTOGRAM_ENUMERATION("Media.AudioInputControllerSessionSilenceReport",
 673                             value,
 674                             SILENCE_STATE_MAX + 1);
 675 }
 676 #endif
 677
 678 }  // namespace media