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1 /* | 1 /* |
2 * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved. | 2 * Copyright (c) 2014 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_MODULES_REMOTE_BITRATE_ESTIMATOR_AIMD_RATE_CONTROL_H_ | 11 #ifndef WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_AIMD_RATE_CONTROL_H_ |
12 #define WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_AIMD_RATE_CONTROL_H_ | 12 #define WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_AIMD_RATE_CONTROL_H_ |
13 | 13 |
14 #include "webrtc/base/constructormagic.h" | 14 #include "webrtc/base/constructormagic.h" |
15 #include "webrtc/modules/remote_bitrate_estimator/include/bwe_defines.h" | 15 #include "webrtc/modules/remote_bitrate_estimator/include/bwe_defines.h" |
16 | 16 |
17 namespace webrtc { | 17 namespace webrtc { |
18 | 18 |
19 // A rate control implementation based on additive increases of | 19 // A rate control implementation based on additive increases of |
20 // bitrate when no over-use is detected and multiplicative decreases when | 20 // bitrate when no over-use is detected and multiplicative decreases when |
21 // over-uses are detected. When we think the available bandwidth has changes or | 21 // over-uses are detected. When we think the available bandwidth has changes or |
22 // is unknown, we will switch to a "slow-start mode" where we increase | 22 // is unknown, we will switch to a "slow-start mode" where we increase |
23 // multiplicatively. | 23 // multiplicatively. |
24 class AimdRateControl { | 24 class AimdRateControl { |
25 public: | 25 public: |
26 AimdRateControl(); | 26 AimdRateControl(); |
27 virtual ~AimdRateControl(); | 27 ~AimdRateControl(); |
28 | 28 |
29 // Returns true if there is a valid estimate of the incoming bitrate, false | 29 // Returns true if there is a valid estimate of the incoming bitrate, false |
30 // otherwise. | 30 // otherwise. |
31 bool ValidEstimate() const; | 31 bool ValidEstimate() const; |
32 void SetStartBitrate(int start_bitrate_bps); | 32 void SetStartBitrate(int start_bitrate_bps); |
33 void SetMinBitrate(int min_bitrate_bps); | 33 void SetMinBitrate(int min_bitrate_bps); |
34 int64_t GetFeedbackInterval() const; | 34 int64_t GetFeedbackInterval() const; |
35 // Returns true if the bitrate estimate hasn't been changed for more than | 35 // Returns true if the bitrate estimate hasn't been changed for more than |
36 // an RTT, or if the incoming_bitrate is less than half of the current | 36 // an RTT, or if the incoming_bitrate is less than half of the current |
37 // estimate. Should be used to decide if we should reduce the rate further | 37 // estimate. Should be used to decide if we should reduce the rate further |
38 // when over-using. | 38 // when over-using. |
39 bool TimeToReduceFurther(int64_t time_now, | 39 bool TimeToReduceFurther(int64_t time_now, |
40 uint32_t incoming_bitrate_bps) const; | 40 uint32_t incoming_bitrate_bps) const; |
41 uint32_t LatestEstimate() const; | 41 uint32_t LatestEstimate() const; |
42 void SetRtt(int64_t rtt); | 42 void SetRtt(int64_t rtt); |
43 uint32_t Update(const RateControlInput* input, int64_t now_ms); | 43 uint32_t Update(const RateControlInput* input, int64_t now_ms); |
44 void SetEstimate(int bitrate_bps, int64_t now_ms); | 44 void SetEstimate(int bitrate_bps, int64_t now_ms); |
45 | 45 |
46 // Returns the increase rate which is used when used bandwidth is near the | 46 // Returns the increase rate when used bandwidth is near the link capacity. |
47 // maximal available bandwidth. | 47 int GetNearMaxIncreaseRateBps() const; |
48 virtual int GetNearMaxIncreaseRateBps() const; | 48 // Returns the expected time between overuse signals (assuming steady state). |
49 | 49 int GetExpectedBandwidthPeriodMs() const; |
50 virtual rtc::Optional<int> GetLastBitrateDecreaseBps() const; | |
51 | 50 |
52 private: | 51 private: |
53 // Update the target bitrate according based on, among other things, | 52 // Update the target bitrate according based on, among other things, |
54 // the current rate control state, the current target bitrate and the incoming | 53 // the current rate control state, the current target bitrate and the incoming |
55 // bitrate. When in the "increase" state the bitrate will be increased either | 54 // bitrate. When in the "increase" state the bitrate will be increased either |
56 // additively or multiplicatively depending on the rate control region. When | 55 // additively or multiplicatively depending on the rate control region. When |
57 // in the "decrease" state the bitrate will be decreased to slightly below the | 56 // in the "decrease" state the bitrate will be decreased to slightly below the |
58 // incoming bitrate. When in the "hold" state the bitrate will be kept | 57 // incoming bitrate. When in the "hold" state the bitrate will be kept |
59 // constant to allow built up queues to drain. | 58 // constant to allow built up queues to drain. |
60 uint32_t ChangeBitrate(uint32_t current_bitrate, | 59 uint32_t ChangeBitrate(uint32_t current_bitrate, |
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84 int64_t time_first_incoming_estimate_; | 83 int64_t time_first_incoming_estimate_; |
85 bool bitrate_is_initialized_; | 84 bool bitrate_is_initialized_; |
86 float beta_; | 85 float beta_; |
87 int64_t rtt_; | 86 int64_t rtt_; |
88 bool in_experiment_; | 87 bool in_experiment_; |
89 rtc::Optional<int> last_decrease_; | 88 rtc::Optional<int> last_decrease_; |
90 }; | 89 }; |
91 } // namespace webrtc | 90 } // namespace webrtc |
92 | 91 |
93 #endif // WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_AIMD_RATE_CONTROL_H_ | 92 #endif // WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_AIMD_RATE_CONTROL_H_ |
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