Added functionality for specifying the initial signal level to use for the gain estimation in the l…

webrtc/modules/audio_processing/level_controller/level_controller.cc

Index: webrtc/modules/audio_processing/level_controller/level_controller.cc
diff --git a/webrtc/modules/audio_processing/level_controller/level_controller.cc b/webrtc/modules/audio_processing/level_controller/level_controller.cc
index bd8d439874899321035a00dfccc16614555a965e..4d2090223decd4f81e1d5fb8f75205cfe572f57e 100644
--- a/webrtc/modules/audio_processing/level_controller/level_controller.cc
+++ b/webrtc/modules/audio_processing/level_controller/level_controller.cc
@@ -155,6 +155,11 @@ LevelController::LevelController()
 
 LevelController::~LevelController() {}
 
+void LevelController::SetInitialLevel(float level) {
+  peak_level_estimator_.SetInitialLevel(level);
+  gain_jumpstart_ = true;
+}
+
 void LevelController::Initialize(int sample_rate_hz) {
   RTC_DCHECK(sample_rate_hz == AudioProcessing::kSampleRate8kHz ||
              sample_rate_hz == AudioProcessing::kSampleRate16kHz ||
@@ -206,8 +211,11 @@ void LevelController::Process(AudioBuffer* audio) {
   float saturating_gain = saturating_gain_estimator_.GetGain();
 
   // Compute the new gain to apply.
-  last_gain_ = gain_selector_.GetNewGain(peak_level, noise_energy,
-                                         saturating_gain, signal_type);
+  last_gain_ = gain_selector_.GetNewGain(
+      peak_level, noise_energy, saturating_gain, gain_jumpstart_, signal_type);
+
+  // Unflag the jumpstart of the gain as it should only happen once.
+  gain_jumpstart_ = false;
 
   // Apply the gain to the signal.
   int num_saturations = gain_applier_.Process(last_gain_, audio);