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/*
* Copyright (c) 2014 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.
*/
#ifndef MODULES_AUDIO_PROCESSING_TYPING_DETECTION_H_
#define MODULES_AUDIO_PROCESSING_TYPING_DETECTION_H_
#include "rtc_base/system/rtc_export.h"
namespace webrtc {
class RTC_EXPORT TypingDetection {
public:
TypingDetection();
virtual ~TypingDetection();
// Run the detection algortihm. Shall be called every 10 ms. Returns true if
// typing is detected, or false if not, based on the update period as set with
// SetParameters(). See `report_detection_update_period_` description below.
bool Process(bool key_pressed, bool vad_activity);
// Gets the time in seconds since the last detection.
int TimeSinceLastDetectionInSeconds();
// Sets the algorithm parameters. A parameter value of 0 leaves it unchanged.
// See the correspondning member variables below for descriptions.
void SetParameters(int time_window,
int cost_per_typing,
int reporting_threshold,
int penalty_decay,
int type_event_delay,
int report_detection_update_period);
private:
int time_active_;
int time_since_last_typing_;
int penalty_counter_;
// Counter since last time the detection status reported by Process() was
// updated. See also `report_detection_update_period_`.
int counter_since_last_detection_update_;
// The detection status to report. Updated every
// `report_detection_update_period_` call to Process().
bool detection_to_report_;
// What `detection_to_report_` should be set to next time it is updated.
bool new_detection_to_report_;
// Settable threshold values.
// Number of 10 ms slots accepted to count as a hit.
int time_window_;
// Penalty added for a typing + activity coincide.
int cost_per_typing_;
// Threshold for `penalty_counter_`.
int reporting_threshold_;
// How much we reduce `penalty_counter_` every 10 ms.
int penalty_decay_;
// How old typing events we allow.
int type_event_delay_;
// Settable update period.
// Number of 10 ms slots between each update of the detection status returned
// by Process(). This inertia added to the algorithm is usually desirable and
// provided so that consumers of the class don't have to implement that
// themselves if they don't wish.
// If set to 1, each call to Process() will return the detection status for
// that 10 ms slot.
// If set to N (where N > 1), the detection status returned from Process()
// will remain the same until Process() has been called N times. Then, if none
// of the last N calls to Process() has detected typing for each respective
// 10 ms slot, Process() will return false. If at least one of the last N
// calls has detected typing, Process() will return true. And that returned
// status will then remain the same until the next N calls have been done.
int report_detection_update_period_;
};
} // namespace webrtc
#endif // #ifndef MODULES_AUDIO_PROCESSING_TYPING_DETECTION_H_