1 files changed, 135 insertions, 0 deletions
diff --git a/chromium/third_party/webrtc/modules/audio_coding/neteq/comfort_noise.cc b/chromium/third_party/webrtc/modules/audio_coding/neteq/comfort_noise.cc
new file mode 100644
index 00000000000..31bb40c9275
--- /dev/null
+++ b/chromium/third_party/webrtc/modules/audio_coding/neteq/comfort_noise.cc
@@ -0,0 +1,135 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq/comfort_noise.h"
+
+#include <assert.h>
+
+#include "webrtc/modules/audio_coding/codecs/cng/include/webrtc_cng.h"
+#include "webrtc/modules/audio_coding/neteq/decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq/dsp_helper.h"
+#include "webrtc/modules/audio_coding/neteq/interface/audio_decoder.h"
+#include "webrtc/modules/audio_coding/neteq/sync_buffer.h"
+
+namespace webrtc {
+
+void ComfortNoise::Reset() {
+  first_call_ = true;
+  internal_error_code_ = 0;
+}
+
+int ComfortNoise::UpdateParameters(Packet* packet) {
+  assert(packet);  // Existence is verified by caller.
+  // Get comfort noise decoder.
+  AudioDecoder* cng_decoder = decoder_database_->GetDecoder(
+      packet->header.payloadType);
+  if (!cng_decoder) {
+    delete [] packet->payload;
+    delete packet;
+    return kUnknownPayloadType;
+  }
+  decoder_database_->SetActiveCngDecoder(packet->header.payloadType);
+  CNG_dec_inst* cng_inst = static_cast<CNG_dec_inst*>(cng_decoder->state());
+  int16_t ret = WebRtcCng_UpdateSid(cng_inst,
+                                    packet->payload,
+                                    packet->payload_length);
+  delete [] packet->payload;
+  delete packet;
+  if (ret < 0) {
+    internal_error_code_ = WebRtcCng_GetErrorCodeDec(cng_inst);
+    return kInternalError;
+  }
+  return kOK;
+}
+
+int ComfortNoise::Generate(size_t requested_length,
+                           AudioMultiVector* output) {
+  // TODO(hlundin): Change to an enumerator and skip assert.
+  assert(fs_hz_ == 8000 || fs_hz_ == 16000 || fs_hz_ ==  32000 ||
+         fs_hz_ == 48000);
+  // Not adapted for multi-channel yet.
+  if (output->Channels() != 1) {
+    return kMultiChannelNotSupported;
+  }
+
+  size_t number_of_samples = requested_length;
+  int16_t new_period = 0;
+  if (first_call_) {
+    // Generate noise and overlap slightly with old data.
+    number_of_samples = requested_length + overlap_length_;
+    new_period = 1;
+  }
+  output->AssertSize(number_of_samples);
+  // Get the decoder from the database.
+  AudioDecoder* cng_decoder = decoder_database_->GetActiveCngDecoder();
+  if (!cng_decoder) {
+    return kUnknownPayloadType;
+  }
+  CNG_dec_inst* cng_inst = static_cast<CNG_dec_inst*>(cng_decoder->state());
+  // The expression &(*output)[0][0] is a pointer to the first element in
+  // the first channel.
+  if (WebRtcCng_Generate(cng_inst, &(*output)[0][0],
+                         static_cast<int16_t>(number_of_samples),
+                         new_period) < 0) {
+    // Error returned.
+    output->Zeros(requested_length);
+    internal_error_code_ = WebRtcCng_GetErrorCodeDec(cng_inst);
+    return kInternalError;
+  }
+
+  if (first_call_) {
+    // Set tapering window parameters. Values are in Q15.
+    int16_t muting_window;  // Mixing factor for overlap data.
+    int16_t muting_window_increment;  // Mixing factor increment (negative).
+    int16_t unmuting_window;  // Mixing factor for comfort noise.
+    int16_t unmuting_window_increment;  // Mixing factor increment.
+    if (fs_hz_ == 8000) {
+      muting_window = DspHelper::kMuteFactorStart8kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement8kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart8kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement8kHz;
+    } else if (fs_hz_ == 16000) {
+      muting_window = DspHelper::kMuteFactorStart16kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement16kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart16kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement16kHz;
+    } else if (fs_hz_ == 32000) {
+      muting_window = DspHelper::kMuteFactorStart32kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement32kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart32kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement32kHz;
+    } else {  // fs_hz_ == 48000
+      muting_window = DspHelper::kMuteFactorStart48kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement48kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart48kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement48kHz;
+    }
+
+    // Do overlap-add between new vector and overlap.
+    size_t start_ix = sync_buffer_->Size() - overlap_length_;
+    for (size_t i = 0; i < overlap_length_; i++) {
+      /* overlapVec[i] = WinMute * overlapVec[i] + WinUnMute * outData[i] */
+      // The expression (*output)[0][i] is the i-th element in the first
+      // channel.
+      (*sync_buffer_)[0][start_ix + i] =
+          (((*sync_buffer_)[0][start_ix + i] * muting_window) +
+              ((*output)[0][i] * unmuting_window) + 16384) >> 15;
+      muting_window += muting_window_increment;
+      unmuting_window += unmuting_window_increment;
+    }
+    // Remove |overlap_length_| samples from the front of |output| since they
+    // were mixed into |sync_buffer_| above.
+    output->PopFront(overlap_length_);
+  }
+  first_call_ = false;
+  return kOK;
+}
+
+}  // namespace webrtc