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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/browser/speech/endpointer/endpointer.h"
#include "base/time/time.h"
#include "content/browser/speech/audio_buffer.h"
using base::Time;
namespace {
const int kFrameRate = 50; // 1 frame = 20ms of audio.
}
namespace content {
Endpointer::Endpointer(int sample_rate)
: speech_input_possibly_complete_silence_length_us_(-1),
speech_input_complete_silence_length_us_(-1),
audio_frame_time_us_(0),
sample_rate_(sample_rate),
frame_size_(0) {
Reset();
frame_size_ = static_cast<int>(sample_rate / static_cast<float>(kFrameRate));
speech_input_minimum_length_us_ =
static_cast<int64>(1.7 * Time::kMicrosecondsPerSecond);
speech_input_complete_silence_length_us_ =
static_cast<int64>(0.5 * Time::kMicrosecondsPerSecond);
long_speech_input_complete_silence_length_us_ = -1;
long_speech_length_us_ = -1;
speech_input_possibly_complete_silence_length_us_ =
1 * Time::kMicrosecondsPerSecond;
// Set the default configuration for Push To Talk mode.
EnergyEndpointerParams ep_config;
ep_config.set_frame_period(1.0f / static_cast<float>(kFrameRate));
ep_config.set_frame_duration(1.0f / static_cast<float>(kFrameRate));
ep_config.set_endpoint_margin(0.2f);
ep_config.set_onset_window(0.15f);
ep_config.set_speech_on_window(0.4f);
ep_config.set_offset_window(0.15f);
ep_config.set_onset_detect_dur(0.09f);
ep_config.set_onset_confirm_dur(0.075f);
ep_config.set_on_maintain_dur(0.10f);
ep_config.set_offset_confirm_dur(0.12f);
ep_config.set_decision_threshold(1000.0f);
ep_config.set_min_decision_threshold(50.0f);
ep_config.set_fast_update_dur(0.2f);
ep_config.set_sample_rate(static_cast<float>(sample_rate));
ep_config.set_min_fundamental_frequency(57.143f);
ep_config.set_max_fundamental_frequency(400.0f);
ep_config.set_contamination_rejection_period(0.25f);
energy_endpointer_.Init(ep_config);
}
void Endpointer::Reset() {
old_ep_status_ = EP_PRE_SPEECH;
waiting_for_speech_possibly_complete_timeout_ = false;
waiting_for_speech_complete_timeout_ = false;
speech_previously_detected_ = false;
speech_input_complete_ = false;
audio_frame_time_us_ = 0; // Reset time for packets sent to endpointer.
speech_end_time_us_ = -1;
speech_start_time_us_ = -1;
}
void Endpointer::StartSession() {
Reset();
energy_endpointer_.StartSession();
}
void Endpointer::EndSession() {
energy_endpointer_.EndSession();
}
void Endpointer::SetEnvironmentEstimationMode() {
Reset();
energy_endpointer_.SetEnvironmentEstimationMode();
}
void Endpointer::SetUserInputMode() {
energy_endpointer_.SetUserInputMode();
}
EpStatus Endpointer::Status(int64 *time) {
return energy_endpointer_.Status(time);
}
EpStatus Endpointer::ProcessAudio(const AudioChunk& raw_audio, float* rms_out) {
const int16* audio_data = raw_audio.SamplesData16();
const int num_samples = raw_audio.NumSamples();
EpStatus ep_status = EP_PRE_SPEECH;
// Process the input data in blocks of frame_size_, dropping any incomplete
// frames at the end (which is ok since typically the caller will be recording
// audio in multiples of our frame size).
int sample_index = 0;
while (sample_index + frame_size_ <= num_samples) {
// Have the endpointer process the frame.
energy_endpointer_.ProcessAudioFrame(audio_frame_time_us_,
audio_data + sample_index,
frame_size_,
rms_out);
sample_index += frame_size_;
audio_frame_time_us_ += (frame_size_ * Time::kMicrosecondsPerSecond) /
sample_rate_;
// Get the status of the endpointer.
int64 ep_time;
ep_status = energy_endpointer_.Status(&ep_time);
// Handle state changes.
if ((EP_SPEECH_PRESENT == ep_status) &&
(EP_POSSIBLE_ONSET == old_ep_status_)) {
speech_end_time_us_ = -1;
waiting_for_speech_possibly_complete_timeout_ = false;
waiting_for_speech_complete_timeout_ = false;
// Trigger SpeechInputDidStart event on first detection.
if (false == speech_previously_detected_) {
speech_previously_detected_ = true;
speech_start_time_us_ = ep_time;
}
}
if ((EP_PRE_SPEECH == ep_status) &&
(EP_POSSIBLE_OFFSET == old_ep_status_)) {
speech_end_time_us_ = ep_time;
waiting_for_speech_possibly_complete_timeout_ = true;
waiting_for_speech_complete_timeout_ = true;
}
if (ep_time > speech_input_minimum_length_us_) {
// Speech possibly complete timeout.
if ((waiting_for_speech_possibly_complete_timeout_) &&
(ep_time - speech_end_time_us_ >
speech_input_possibly_complete_silence_length_us_)) {
waiting_for_speech_possibly_complete_timeout_ = false;
}
if (waiting_for_speech_complete_timeout_) {
// The length of the silence timeout period can be held constant, or it
// can be changed after a fixed amount of time from the beginning of
// speech.
bool has_stepped_silence =
(long_speech_length_us_ > 0) &&
(long_speech_input_complete_silence_length_us_ > 0);
int64 requested_silence_length;
if (has_stepped_silence &&
(ep_time - speech_start_time_us_) > long_speech_length_us_) {
requested_silence_length =
long_speech_input_complete_silence_length_us_;
} else {
requested_silence_length =
speech_input_complete_silence_length_us_;
}
// Speech complete timeout.
if ((ep_time - speech_end_time_us_) > requested_silence_length) {
waiting_for_speech_complete_timeout_ = false;
speech_input_complete_ = true;
}
}
}
old_ep_status_ = ep_status;
}
return ep_status;
}
} // namespace content
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