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1 /* | 1 /* |
2 * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. | 2 * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. |
3 * | 3 * |
4 * Use of this source code is governed by a BSD-style license | 4 * Use of this source code is governed by a BSD-style license |
5 * that can be found in the LICENSE file in the root of the source | 5 * that can be found in the LICENSE file in the root of the source |
6 * tree. An additional intellectual property rights grant can be found | 6 * tree. An additional intellectual property rights grant can be found |
7 * in the file PATENTS. All contributing project authors may | 7 * in the file PATENTS. All contributing project authors may |
8 * be found in the AUTHORS file in the root of the source tree. | 8 * be found in the AUTHORS file in the root of the source tree. |
9 */ | 9 */ |
10 | 10 |
11 #ifndef WEBRTC_BASE_SMOOTHING_FILTER_H_ | 11 #ifndef WEBRTC_BASE_SMOOTHING_FILTER_H_ |
12 #define WEBRTC_BASE_SMOOTHING_FILTER_H_ | 12 #define WEBRTC_BASE_SMOOTHING_FILTER_H_ |
13 | 13 |
14 #include "webrtc/base/constructormagic.h" | 14 #include "webrtc/base/constructormagic.h" |
15 #include "webrtc/base/exp_filter.h" | 15 #include "webrtc/base/exp_filter.h" |
16 #include "webrtc/base/optional.h" | 16 #include "webrtc/base/optional.h" |
17 #include "webrtc/system_wrappers/include/clock.h" | 17 #include "webrtc/system_wrappers/include/clock.h" |
18 | 18 |
19 namespace webrtc { | 19 namespace webrtc { |
20 | 20 |
21 class SmoothingFilter { | 21 class SmoothingFilter { |
22 public: | 22 public: |
23 virtual ~SmoothingFilter() = default; | 23 virtual ~SmoothingFilter() = default; |
24 virtual void AddSample(float sample) = 0; | 24 virtual void AddSample(float sample) = 0; |
25 virtual rtc::Optional<float> GetAverage() const = 0; | 25 virtual rtc::Optional<float> GetAverage() const = 0; |
| 26 virtual void SetTimeConstantMs(int time_constant_ms) = 0; |
26 }; | 27 }; |
27 | 28 |
28 // SmoothingFilterImpl applies an exponential filter | 29 // SmoothingFilterImpl applies an exponential filter |
29 // alpha = exp(-sample_interval / time_constant); | 30 // alpha = exp(-sample_interval / time_constant); |
30 // y[t] = alpha * y[t-1] + (1 - alpha) * sample; | 31 // y[t] = alpha * y[t-1] + (1 - alpha) * sample; |
31 class SmoothingFilterImpl final : public SmoothingFilter { | 32 class SmoothingFilterImpl final : public SmoothingFilter { |
32 public: | 33 public: |
33 // |time_constant_ms| is the time constant for the exponential filter. | 34 // |time_constant_ms| is the time constant for the exponential filter. |
34 SmoothingFilterImpl(int time_constant_ms, const Clock* clock); | 35 SmoothingFilterImpl(int time_constant_ms, const Clock* clock); |
35 | 36 |
36 void AddSample(float sample) override; | 37 void AddSample(float sample) override; |
37 rtc::Optional<float> GetAverage() const override; | 38 rtc::Optional<float> GetAverage() const override; |
| 39 void SetTimeConstantMs(int time_constant_ms) override; |
38 | 40 |
39 private: | 41 private: |
40 const int time_constant_ms_; | 42 int time_constant_ms_; |
41 const Clock* const clock_; | 43 const Clock* const clock_; |
42 | 44 |
43 bool first_sample_received_; | 45 bool first_sample_received_; |
44 bool initialized_; | 46 bool initialized_; |
45 int64_t first_sample_time_ms_; | 47 int64_t first_sample_time_ms_; |
46 int64_t last_sample_time_ms_; | 48 int64_t last_sample_time_ms_; |
47 rtc::ExpFilter filter_; | 49 rtc::ExpFilter filter_; |
48 | 50 |
49 RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(SmoothingFilterImpl); | 51 RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(SmoothingFilterImpl); |
50 }; | 52 }; |
51 | 53 |
52 } // namespace webrtc | 54 } // namespace webrtc |
53 | 55 |
54 #endif // WEBRTC_BASE_SMOOTHING_FILTER_H_ | 56 #endif // WEBRTC_BASE_SMOOTHING_FILTER_H_ |
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