Introduced the new parameter setting scheme for activating the high-pass filter in APM

webrtc/modules/audio_processing/low_cut_filter.cc

Index: webrtc/modules/audio_processing/low_cut_filter.cc
diff --git a/webrtc/modules/audio_processing/high_pass_filter_impl.cc b/webrtc/modules/audio_processing/low_cut_filter.cc
similarity index 63%
rename from webrtc/modules/audio_processing/high_pass_filter_impl.cc
rename to webrtc/modules/audio_processing/low_cut_filter.cc
index d33ec78dcbca29b7214d338600864812a0d05e03..77dab9af43c735e328077d4eb030104ca9006c7b 100644
--- a/webrtc/modules/audio_processing/high_pass_filter_impl.cc
+++ b/webrtc/modules/audio_processing/low_cut_filter.cc
@@ -8,7 +8,7 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include "webrtc/modules/audio_processing/high_pass_filter_impl.h"
+#include "webrtc/modules/audio_processing/low_cut_filter.h"
 
 #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
 #include "webrtc/modules/audio_processing/audio_buffer.h"
@@ -20,16 +20,12 @@ const int16_t kFilterCoefficients8kHz[5] = {3798, -7596, 3798, 7807, -3733};
 const int16_t kFilterCoefficients[5] = {4012, -8024, 4012, 8002, -3913};
 }  // namespace
 
-class HighPassFilterImpl::BiquadFilter {
+class LowCutFilter::BiquadFilter {
  public:
-  explicit BiquadFilter(int sample_rate_hz) :
-      ba_(sample_rate_hz == AudioProcessing::kSampleRate8kHz ?
-          kFilterCoefficients8kHz : kFilterCoefficients)
-  {
-    Reset();
-  }
-
-  void Reset() {
+  explicit BiquadFilter(int sample_rate_hz)
+      : ba_(sample_rate_hz == AudioProcessing::kSampleRate8kHz
+                ? kFilterCoefficients8kHz
+                : kFilterCoefficients) {
     std::memset(x_, 0, sizeof(x_));
     std::memset(y_, 0, sizeof(y_));
   }
@@ -44,11 +40,11 @@ class HighPassFilterImpl::BiquadFilter {
       //  y[i] = b[0] * x[i] +  b[1] * x[i-1] +  b[2] * x[i-2]
       //                     + -a[1] * y[i-1] + -a[2] * y[i-2];
 
-      tmp_int32 = y[1] * ba[3];      // -a[1] * y[i-1] (low part)
-      tmp_int32 += y[3] * ba[4];     // -a[2] * y[i-2] (low part)
+      tmp_int32 = y[1] * ba[3];   // -a[1] * y[i-1] (low part)
+      tmp_int32 += y[3] * ba[4];  // -a[2] * y[i-2] (low part)
       tmp_int32 = (tmp_int32 >> 15);
-      tmp_int32 += y[0] * ba[3];     // -a[1] * y[i-1] (high part)
-      tmp_int32 += y[2] * ba[4];     // -a[2] * y[i-2] (high part)
+      tmp_int32 += y[0] * ba[3];  // -a[1] * y[i-1] (high part)
+      tmp_int32 += y[2] * ba[4];  // -a[2] * y[i-2] (high part)
       tmp_int32 = (tmp_int32 << 1);
 
       tmp_int32 += data[i] * ba[0];  // b[0] * x[0]
@@ -70,8 +66,7 @@ class HighPassFilterImpl::BiquadFilter {
       tmp_int32 += 2048;
 
       // Saturate (to 2^27) so that the HP filtered signal does not overflow.
-      tmp_int32 = WEBRTC_SPL_SAT(static_cast<int32_t>(134217727),
-                                 tmp_int32,
+      tmp_int32 = WEBRTC_SPL_SAT(static_cast<int32_t>(134217727), tmp_int32,
                                  static_cast<int32_t>(-134217728));
 
       // Convert back to Q0 and use rounding.
@@ -85,29 +80,17 @@ class HighPassFilterImpl::BiquadFilter {
   int16_t y_[4];
 };
 
-HighPassFilterImpl::HighPassFilterImpl(rtc::CriticalSection* crit)
-    : crit_(crit) {
-  RTC_DCHECK(crit_);
-}
-
-HighPassFilterImpl::~HighPassFilterImpl() {}
-
-void HighPassFilterImpl::Initialize(size_t channels, int sample_rate_hz) {
-  std::vector<std::unique_ptr<BiquadFilter>> new_filters(channels);
+LowCutFilter::LowCutFilter(size_t channels, int sample_rate_hz) {
+  filters_.resize(channels);
   for (size_t i = 0; i < channels; i++) {
-    new_filters[i].reset(new BiquadFilter(sample_rate_hz));
+    filters_[i].reset(new BiquadFilter(sample_rate_hz));
   }
-  rtc::CritScope cs(crit_);
-  filters_.swap(new_filters);
 }
 
-void HighPassFilterImpl::ProcessCaptureAudio(AudioBuffer* audio) {
-  RTC_DCHECK(audio);
-  rtc::CritScope cs(crit_);
-  if (!enabled_) {
-    return;
-  }
+LowCutFilter::~LowCutFilter() {}
 
+void LowCutFilter::Process(AudioBuffer* audio) {
+  RTC_DCHECK(audio);
   RTC_DCHECK_GE(160u, audio->num_frames_per_band());
   RTC_DCHECK_EQ(filters_.size(), audio->num_channels());
   for (size_t i = 0; i < filters_.size(); i++) {
@@ -116,19 +99,4 @@ void HighPassFilterImpl::ProcessCaptureAudio(AudioBuffer* audio) {
   }
 }
 
-int HighPassFilterImpl::Enable(bool enable) {
-  rtc::CritScope cs(crit_);
-  if (!enabled_ && enable) {
-    for (auto& filter : filters_) {
-      filter->Reset();
-    }
-  }
-  enabled_ = enable;
-  return AudioProcessing::kNoError;
-}
-
-bool HighPassFilterImpl::is_enabled() const {
-  rtc::CritScope cs(crit_);
-  return enabled_;
-}
 }  // namespace webrtc