1 /*
2  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
3  *
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
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include <algorithm>
12 #include <memory>
13 #include <vector>
14 
15 #include "call/bitrate_allocator.h"
16 #include "modules/bitrate_controller/include/bitrate_controller.h"
17 #include "test/gmock.h"
18 #include "test/gtest.h"
19 
20 using ::testing::NiceMock;
21 using ::testing::_;
22 
23 namespace webrtc {
24 
25 class MockLimitObserver : public BitrateAllocator::LimitObserver {
26  public:
27   MOCK_METHOD2(OnAllocationLimitsChanged,
28                void(uint32_t min_send_bitrate_bps,
29                     uint32_t max_padding_bitrate_bps));
30 };
31 
32 class TestBitrateObserver : public BitrateAllocatorObserver {
33  public:
TestBitrateObserver()34   TestBitrateObserver()
35       : last_bitrate_bps_(0),
36         last_fraction_loss_(0),
37         last_rtt_ms_(0),
38         last_probing_interval_ms_(0),
39         protection_ratio_(0.0) {}
40 
SetBitrateProtectionRatio(double protection_ratio)41   void SetBitrateProtectionRatio(double protection_ratio) {
42     protection_ratio_ = protection_ratio;
43   }
44 
OnBitrateUpdated(uint32_t bitrate_bps,uint8_t fraction_loss,int64_t rtt,int64_t probing_interval_ms)45   uint32_t OnBitrateUpdated(uint32_t bitrate_bps,
46                             uint8_t fraction_loss,
47                             int64_t rtt,
48                             int64_t probing_interval_ms) override {
49     last_bitrate_bps_ = bitrate_bps;
50     last_fraction_loss_ = fraction_loss;
51     last_rtt_ms_ = rtt;
52     last_probing_interval_ms_ = probing_interval_ms;
53     return bitrate_bps * protection_ratio_;
54   }
55   uint32_t last_bitrate_bps_;
56   uint8_t last_fraction_loss_;
57   int64_t last_rtt_ms_;
58   int last_probing_interval_ms_;
59   double protection_ratio_;
60 };
61 
62 namespace {
63 constexpr int64_t kDefaultProbingIntervalMs = 3000;
64 }
65 
66 class BitrateAllocatorTest : public ::testing::Test {
67  protected:
BitrateAllocatorTest()68   BitrateAllocatorTest() : allocator_(new BitrateAllocator(&limit_observer_)) {
69     allocator_->OnNetworkChanged(300000u, 0, 0, kDefaultProbingIntervalMs);
70   }
~BitrateAllocatorTest()71   ~BitrateAllocatorTest() {}
72 
73   NiceMock<MockLimitObserver> limit_observer_;
74   std::unique_ptr<BitrateAllocator> allocator_;
75 };
76 
TEST_F(BitrateAllocatorTest,UpdatingBitrateObserver)77 TEST_F(BitrateAllocatorTest, UpdatingBitrateObserver) {
78   TestBitrateObserver bitrate_observer;
79   const uint32_t kMinSendBitrateBps = 100000;
80   const uint32_t kPadUpToBitrateBps = 50000;
81 
82   EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(kMinSendBitrateBps,
83                                                          kPadUpToBitrateBps));
84   allocator_->AddObserver(&bitrate_observer, kMinSendBitrateBps, 1500000,
85                           kPadUpToBitrateBps, true, "");
86   EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer));
87   allocator_->OnNetworkChanged(200000, 0, 0, kDefaultProbingIntervalMs);
88   EXPECT_EQ(200000, allocator_->GetStartBitrate(&bitrate_observer));
89 
90   // TODO(pbos): Expect capping to 1.5M instead of 3M when not boosting the max
91   // bitrate for FEC/retransmissions (see todo in BitrateAllocator).
92   allocator_->OnNetworkChanged(4000000, 0, 0, kDefaultProbingIntervalMs);
93   EXPECT_EQ(3000000, allocator_->GetStartBitrate(&bitrate_observer));
94 
95   // Expect |max_padding_bitrate_bps| to change to 0 if the observer is updated.
96   EXPECT_CALL(limit_observer_,
97               OnAllocationLimitsChanged(kMinSendBitrateBps, 0));
98   allocator_->AddObserver(&bitrate_observer, kMinSendBitrateBps, 4000000, 0,
99                           true, "");
100   EXPECT_EQ(4000000, allocator_->GetStartBitrate(&bitrate_observer));
101 
102   allocator_->AddObserver(&bitrate_observer, kMinSendBitrateBps, 1500000, 0,
103                           true, "");
104   EXPECT_EQ(3000000, allocator_->GetStartBitrate(&bitrate_observer));
105   EXPECT_EQ(3000000u, bitrate_observer.last_bitrate_bps_);
106   allocator_->OnNetworkChanged(1500000, 0, 0, kDefaultProbingIntervalMs);
107   EXPECT_EQ(1500000u, bitrate_observer.last_bitrate_bps_);
108 }
109 
TEST_F(BitrateAllocatorTest,TwoBitrateObserversOneRtcpObserver)110 TEST_F(BitrateAllocatorTest, TwoBitrateObserversOneRtcpObserver) {
111   TestBitrateObserver bitrate_observer_1;
112   TestBitrateObserver bitrate_observer_2;
113   EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(100000, 0));
114   allocator_->AddObserver(&bitrate_observer_1, 100000, 300000, 0, true, "");
115   EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_1));
116   EXPECT_CALL(limit_observer_,
117               OnAllocationLimitsChanged(100000 + 200000, 0));
118   allocator_->AddObserver(&bitrate_observer_2, 200000, 300000, 0, true, "");
119   EXPECT_EQ(200000, allocator_->GetStartBitrate(&bitrate_observer_2));
120 
121   // Test too low start bitrate, hence lower than sum of min. Min bitrates
122   // will
123   // be allocated to all observers.
124   allocator_->OnNetworkChanged(200000, 0, 50, kDefaultProbingIntervalMs);
125   EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
126   EXPECT_EQ(0, bitrate_observer_1.last_fraction_loss_);
127   EXPECT_EQ(50, bitrate_observer_1.last_rtt_ms_);
128   EXPECT_EQ(200000u, bitrate_observer_2.last_bitrate_bps_);
129   EXPECT_EQ(0, bitrate_observer_2.last_fraction_loss_);
130   EXPECT_EQ(50, bitrate_observer_2.last_rtt_ms_);
131 
132   // Test a bitrate which should be distributed equally.
133   allocator_->OnNetworkChanged(500000, 0, 50, kDefaultProbingIntervalMs);
134   const uint32_t kBitrateToShare = 500000 - 200000 - 100000;
135   EXPECT_EQ(100000u + kBitrateToShare / 2,
136             bitrate_observer_1.last_bitrate_bps_);
137   EXPECT_EQ(200000u + kBitrateToShare / 2,
138             bitrate_observer_2.last_bitrate_bps_);
139 
140   // Limited by 2x max bitrates since we leave room for FEC and
141   // retransmissions.
142   allocator_->OnNetworkChanged(1500000, 0, 50, kDefaultProbingIntervalMs);
143   EXPECT_EQ(600000u, bitrate_observer_1.last_bitrate_bps_);
144   EXPECT_EQ(600000u, bitrate_observer_2.last_bitrate_bps_);
145 
146   // Verify that if the bandwidth estimate is set to zero, the allocated
147   // rate is
148   // zero.
149   allocator_->OnNetworkChanged(0, 0, 50, kDefaultProbingIntervalMs);
150   EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
151   EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
152 }
153 
TEST_F(BitrateAllocatorTest,RemoveObserverTriggersLimitObserver)154 TEST_F(BitrateAllocatorTest, RemoveObserverTriggersLimitObserver) {
155   TestBitrateObserver bitrate_observer;
156   const uint32_t kMinSendBitrateBps = 100000;
157   const uint32_t kPadUpToBitrateBps = 50000;
158 
159   EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(kMinSendBitrateBps,
160                                                          kPadUpToBitrateBps));
161   allocator_->AddObserver(&bitrate_observer, kMinSendBitrateBps, 1500000,
162                           kPadUpToBitrateBps, true, "");
163   EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(0, 0));
164   allocator_->RemoveObserver(&bitrate_observer);
165 }
166 
167 class BitrateAllocatorTestNoEnforceMin : public ::testing::Test {
168  protected:
BitrateAllocatorTestNoEnforceMin()169   BitrateAllocatorTestNoEnforceMin()
170       : allocator_(new BitrateAllocator(&limit_observer_)) {
171     allocator_->OnNetworkChanged(300000u, 0, 0, kDefaultProbingIntervalMs);
172   }
~BitrateAllocatorTestNoEnforceMin()173   ~BitrateAllocatorTestNoEnforceMin() {}
174 
175   NiceMock<MockLimitObserver> limit_observer_;
176   std::unique_ptr<BitrateAllocator> allocator_;
177 };
178 
179 // The following three tests verify enforcing a minimum bitrate works as
180 // intended.
TEST_F(BitrateAllocatorTestNoEnforceMin,OneBitrateObserver)181 TEST_F(BitrateAllocatorTestNoEnforceMin, OneBitrateObserver) {
182   TestBitrateObserver bitrate_observer_1;
183   // Expect OnAllocationLimitsChanged with |min_send_bitrate_bps| = 0 since
184   // AddObserver is called with |enforce_min_bitrate| = false.
185   EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(0, 120000));
186   allocator_->AddObserver(&bitrate_observer_1, 100000, 400000, 0, false, "");
187   EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_1));
188 
189   // High BWE.
190   allocator_->OnNetworkChanged(150000, 0, 0, kDefaultProbingIntervalMs);
191   EXPECT_EQ(150000u, bitrate_observer_1.last_bitrate_bps_);
192 
193   // Low BWE.
194   allocator_->OnNetworkChanged(10000, 0, 0, kDefaultProbingIntervalMs);
195   EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
196 
197   EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(0, 0));
198   allocator_->RemoveObserver(&bitrate_observer_1);
199 }
200 
TEST_F(BitrateAllocatorTestNoEnforceMin,ThreeBitrateObservers)201 TEST_F(BitrateAllocatorTestNoEnforceMin, ThreeBitrateObservers) {
202   TestBitrateObserver bitrate_observer_1;
203   TestBitrateObserver bitrate_observer_2;
204   TestBitrateObserver bitrate_observer_3;
205   // Set up the observers with min bitrates at 100000, 200000, and 300000.
206   allocator_->AddObserver(&bitrate_observer_1, 100000, 400000, 0, false, "");
207   EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_1));
208 
209   allocator_->AddObserver(&bitrate_observer_2, 200000, 400000, 0, false, "");
210   EXPECT_EQ(200000, allocator_->GetStartBitrate(&bitrate_observer_2));
211   EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
212 
213   allocator_->AddObserver(&bitrate_observer_3, 300000, 400000, 0, false, "");
214   EXPECT_EQ(0, allocator_->GetStartBitrate(&bitrate_observer_3));
215   EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
216   EXPECT_EQ(200000u, bitrate_observer_2.last_bitrate_bps_);
217 
218   // High BWE. Make sure the controllers get a fair share of the surplus (i.e.,
219   // what is left after each controller gets its min rate).
220   allocator_->OnNetworkChanged(690000, 0, 0, kDefaultProbingIntervalMs);
221   // Verify that each observer gets its min rate (sum of min rates is 600000),
222   // and that the remaining 90000 is divided equally among the three.
223   uint32_t bitrate_to_share = 690000u - 100000u - 200000u - 300000u;
224   EXPECT_EQ(100000u + bitrate_to_share / 3,
225             bitrate_observer_1.last_bitrate_bps_);
226   EXPECT_EQ(200000u + bitrate_to_share / 3,
227             bitrate_observer_2.last_bitrate_bps_);
228   EXPECT_EQ(300000u + bitrate_to_share / 3,
229             bitrate_observer_3.last_bitrate_bps_);
230 
231   // BWE below the sum of observer's min bitrate.
232   allocator_->OnNetworkChanged(300000, 0, 0, kDefaultProbingIntervalMs);
233   EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);  // Min bitrate.
234   EXPECT_EQ(200000u, bitrate_observer_2.last_bitrate_bps_);  // Min bitrate.
235   EXPECT_EQ(0u, bitrate_observer_3.last_bitrate_bps_);  // Nothing.
236 
237   // Increased BWE, but still below the sum of configured min bitrates for all
238   // observers and too little for observer 3. 1 and 2 will share the rest.
239   allocator_->OnNetworkChanged(500000, 0, 0, kDefaultProbingIntervalMs);
240   EXPECT_EQ(200000u, bitrate_observer_1.last_bitrate_bps_);  // Min + split.
241   EXPECT_EQ(300000u, bitrate_observer_2.last_bitrate_bps_);  // Min + split.
242   EXPECT_EQ(0u, bitrate_observer_3.last_bitrate_bps_);  // Nothing.
243 
244   // Below min for all.
245   allocator_->OnNetworkChanged(10000, 0, 0, kDefaultProbingIntervalMs);
246   EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
247   EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
248   EXPECT_EQ(0u, bitrate_observer_3.last_bitrate_bps_);
249 
250   // Verify that zero estimated bandwidth, means that that all gets zero,
251   // regardless of set min bitrate.
252   allocator_->OnNetworkChanged(0, 0, 0, kDefaultProbingIntervalMs);
253   EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
254   EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
255   EXPECT_EQ(0u, bitrate_observer_3.last_bitrate_bps_);
256 
257   allocator_->RemoveObserver(&bitrate_observer_1);
258   allocator_->RemoveObserver(&bitrate_observer_2);
259   allocator_->RemoveObserver(&bitrate_observer_3);
260 }
261 
TEST_F(BitrateAllocatorTestNoEnforceMin,OneBitrateObserverWithPacketLoss)262 TEST_F(BitrateAllocatorTestNoEnforceMin, OneBitrateObserverWithPacketLoss) {
263   TestBitrateObserver bitrate_observer;
264   // Expect OnAllocationLimitsChanged with |min_send_bitrate_bps| = 0 since
265   // AddObserver is called with |enforce_min_bitrate| = false.
266   EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(0, 168000));
267   allocator_->AddObserver(&bitrate_observer, 100000, 400000, 0, false, "");
268   EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer));
269 
270   // High BWE.
271   allocator_->OnNetworkChanged(150000, 0, 0, kDefaultProbingIntervalMs);
272   EXPECT_EQ(150000u, bitrate_observer.last_bitrate_bps_);
273 
274   // Add loss and use a part of the bitrate for protection.
275   double protection_ratio = 0.4;
276   uint8_t fraction_loss = protection_ratio * 256;
277   bitrate_observer.SetBitrateProtectionRatio(protection_ratio);
278   allocator_->OnNetworkChanged(200000, 0, fraction_loss,
279                                kDefaultProbingIntervalMs);
280   EXPECT_EQ(200000u, bitrate_observer.last_bitrate_bps_);
281 
282   // Above the min threshold, but not enough given the protection used.
283   allocator_->OnNetworkChanged(139000, 0, fraction_loss,
284                                kDefaultProbingIntervalMs);
285   EXPECT_EQ(0u, bitrate_observer.last_bitrate_bps_);
286 
287   // Verify the hysteresis is added for the protection.
288   allocator_->OnNetworkChanged(150000, 0, fraction_loss,
289                                kDefaultProbingIntervalMs);
290   EXPECT_EQ(0u, bitrate_observer.last_bitrate_bps_);
291 
292   // Just enough to enable video again.
293   EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(0, 0));
294   allocator_->OnNetworkChanged(168000, 0, fraction_loss,
295                                kDefaultProbingIntervalMs);
296   EXPECT_EQ(168000u, bitrate_observer.last_bitrate_bps_);
297 
298   // Remove all protection and make sure video is not paused as earlier.
299   bitrate_observer.SetBitrateProtectionRatio(0.0);
300   allocator_->OnNetworkChanged(140000, 0, 0, kDefaultProbingIntervalMs);
301   EXPECT_EQ(140000u, bitrate_observer.last_bitrate_bps_);
302 
303   allocator_->OnNetworkChanged(139000, 0, 0, kDefaultProbingIntervalMs);
304   EXPECT_EQ(139000u, bitrate_observer.last_bitrate_bps_);
305 
306   allocator_->RemoveObserver(&bitrate_observer);
307 }
308 
TEST_F(BitrateAllocatorTestNoEnforceMin,TwoBitrateObserverWithPacketLoss)309 TEST_F(BitrateAllocatorTestNoEnforceMin, TwoBitrateObserverWithPacketLoss) {
310   TestBitrateObserver bitrate_observer_1;
311   TestBitrateObserver bitrate_observer_2;
312 
313   allocator_->AddObserver(&bitrate_observer_1, 100000, 400000, 0, false, "");
314   EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_1));
315   allocator_->AddObserver(&bitrate_observer_2, 200000, 400000, 0, false, "");
316   EXPECT_EQ(200000, allocator_->GetStartBitrate(&bitrate_observer_2));
317   EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
318 
319   // Enough bitrate for both.
320   bitrate_observer_2.SetBitrateProtectionRatio(0.5);
321   allocator_->OnNetworkChanged(300000, 0, 0, kDefaultProbingIntervalMs);
322   EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
323   EXPECT_EQ(200000u, bitrate_observer_2.last_bitrate_bps_);
324 
325   // Above min for observer 2, but too little given the protection used.
326   allocator_->OnNetworkChanged(330000, 0, 0, kDefaultProbingIntervalMs);
327   EXPECT_EQ(330000u, bitrate_observer_1.last_bitrate_bps_);
328   EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
329 
330   allocator_->OnNetworkChanged(100000, 0, 0, kDefaultProbingIntervalMs);
331   EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
332   EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
333 
334   allocator_->OnNetworkChanged(99999, 0, 0, kDefaultProbingIntervalMs);
335   EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
336   EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
337 
338   allocator_->OnNetworkChanged(119000, 0, 0, kDefaultProbingIntervalMs);
339   EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
340   EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
341 
342   allocator_->OnNetworkChanged(120000, 0, 0, kDefaultProbingIntervalMs);
343   EXPECT_EQ(120000u, bitrate_observer_1.last_bitrate_bps_);
344   EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
345 
346   // Verify the protection is accounted for before resuming observer 2.
347   allocator_->OnNetworkChanged(429000, 0, 0, kDefaultProbingIntervalMs);
348   EXPECT_EQ(400000u, bitrate_observer_1.last_bitrate_bps_);
349   EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
350 
351   allocator_->OnNetworkChanged(430000, 0, 0, kDefaultProbingIntervalMs);
352   EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
353   EXPECT_EQ(330000u, bitrate_observer_2.last_bitrate_bps_);
354 
355   allocator_->RemoveObserver(&bitrate_observer_1);
356   allocator_->RemoveObserver(&bitrate_observer_2);
357 }
358 
TEST_F(BitrateAllocatorTest,ThreeBitrateObserversLowBweEnforceMin)359 TEST_F(BitrateAllocatorTest, ThreeBitrateObserversLowBweEnforceMin) {
360   TestBitrateObserver bitrate_observer_1;
361   TestBitrateObserver bitrate_observer_2;
362   TestBitrateObserver bitrate_observer_3;
363 
364   allocator_->AddObserver(&bitrate_observer_1, 100000, 400000, 0, true, "");
365   EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_1));
366 
367   allocator_->AddObserver(&bitrate_observer_2, 200000, 400000, 0, true, "");
368   EXPECT_EQ(200000, allocator_->GetStartBitrate(&bitrate_observer_2));
369   EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);
370 
371   allocator_->AddObserver(&bitrate_observer_3, 300000, 400000, 0, true, "");
372   EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_3));
373   EXPECT_EQ(100000, static_cast<int>(bitrate_observer_1.last_bitrate_bps_));
374   EXPECT_EQ(200000, static_cast<int>(bitrate_observer_2.last_bitrate_bps_));
375 
376   // Low BWE. Verify that all observers still get their respective min
377   // bitrate.
378   allocator_->OnNetworkChanged(1000, 0, 0, kDefaultProbingIntervalMs);
379   EXPECT_EQ(100000u, bitrate_observer_1.last_bitrate_bps_);  // Min cap.
380   EXPECT_EQ(200000u, bitrate_observer_2.last_bitrate_bps_);  // Min cap.
381   EXPECT_EQ(300000u, bitrate_observer_3.last_bitrate_bps_);  // Min cap.
382 
383   allocator_->RemoveObserver(&bitrate_observer_1);
384   allocator_->RemoveObserver(&bitrate_observer_2);
385   allocator_->RemoveObserver(&bitrate_observer_3);
386 }
387 
TEST_F(BitrateAllocatorTest,AddObserverWhileNetworkDown)388 TEST_F(BitrateAllocatorTest, AddObserverWhileNetworkDown) {
389   TestBitrateObserver bitrate_observer_1;
390   EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(50000, 0));
391 
392   allocator_->AddObserver(&bitrate_observer_1, 50000, 400000, 0, true, "");
393   EXPECT_EQ(300000, allocator_->GetStartBitrate(&bitrate_observer_1));
394 
395   // Set network down, ie, no available bitrate.
396   allocator_->OnNetworkChanged(0, 0, 0, kDefaultProbingIntervalMs);
397 
398   EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
399 
400   TestBitrateObserver bitrate_observer_2;
401   // Adding an observer while the network is down should not affect the limits.
402   EXPECT_CALL(limit_observer_, OnAllocationLimitsChanged(50000 + 50000, 0));
403   allocator_->AddObserver(&bitrate_observer_2, 50000, 400000, 0, true, "");
404 
405   // Expect the start_bitrate to be set as if the network was still up but that
406   // the new observer have been notified that the network is down.
407   EXPECT_EQ(300000 / 2, allocator_->GetStartBitrate(&bitrate_observer_2));
408   EXPECT_EQ(0u, bitrate_observer_1.last_bitrate_bps_);
409   EXPECT_EQ(0u, bitrate_observer_2.last_bitrate_bps_);
410 
411   // Set network back up.
412   allocator_->OnNetworkChanged(1500000, 0, 50, kDefaultProbingIntervalMs);
413   EXPECT_EQ(750000u, bitrate_observer_1.last_bitrate_bps_);
414   EXPECT_EQ(750000u, bitrate_observer_2.last_bitrate_bps_);
415 }
416 
TEST_F(BitrateAllocatorTest,MixedEnforecedConfigs)417 TEST_F(BitrateAllocatorTest, MixedEnforecedConfigs) {
418   TestBitrateObserver enforced_observer;
419   allocator_->AddObserver(&enforced_observer, 6000, 30000, 0, true, "");
420   EXPECT_EQ(60000, allocator_->GetStartBitrate(&enforced_observer));
421 
422   TestBitrateObserver not_enforced_observer;
423   allocator_->AddObserver(&not_enforced_observer, 30000, 2500000, 0, false, "");
424   EXPECT_EQ(270000, allocator_->GetStartBitrate(&not_enforced_observer));
425   EXPECT_EQ(30000u, enforced_observer.last_bitrate_bps_);
426 
427   allocator_->OnNetworkChanged(36000, 0, 50, kDefaultProbingIntervalMs);
428   EXPECT_EQ(6000u, enforced_observer.last_bitrate_bps_);
429   EXPECT_EQ(30000u, not_enforced_observer.last_bitrate_bps_);
430 
431   allocator_->OnNetworkChanged(35000, 0, 50, kDefaultProbingIntervalMs);
432   EXPECT_EQ(30000u, enforced_observer.last_bitrate_bps_);
433   EXPECT_EQ(0u, not_enforced_observer.last_bitrate_bps_);
434 
435   allocator_->OnNetworkChanged(5000, 0, 50, kDefaultProbingIntervalMs);
436   EXPECT_EQ(6000u, enforced_observer.last_bitrate_bps_);
437   EXPECT_EQ(0u, not_enforced_observer.last_bitrate_bps_);
438 
439   allocator_->OnNetworkChanged(36000, 0, 50, kDefaultProbingIntervalMs);
440   EXPECT_EQ(30000u, enforced_observer.last_bitrate_bps_);
441   EXPECT_EQ(0u, not_enforced_observer.last_bitrate_bps_);
442 
443   allocator_->OnNetworkChanged(55000, 0, 50, kDefaultProbingIntervalMs);
444   EXPECT_EQ(30000u, enforced_observer.last_bitrate_bps_);
445   EXPECT_EQ(0u, not_enforced_observer.last_bitrate_bps_);
446 
447   allocator_->OnNetworkChanged(56000, 0, 50, kDefaultProbingIntervalMs);
448   EXPECT_EQ(6000u, enforced_observer.last_bitrate_bps_);
449   EXPECT_EQ(50000u, not_enforced_observer.last_bitrate_bps_);
450 
451   allocator_->OnNetworkChanged(56000, 0, 50, kDefaultProbingIntervalMs);
452   EXPECT_EQ(16000u, enforced_observer.last_bitrate_bps_);
453   EXPECT_EQ(40000u, not_enforced_observer.last_bitrate_bps_);
454 
455   allocator_->RemoveObserver(&enforced_observer);
456   allocator_->RemoveObserver(&not_enforced_observer);
457 }
458 
TEST_F(BitrateAllocatorTest,AvoidToggleAbsolute)459 TEST_F(BitrateAllocatorTest, AvoidToggleAbsolute) {
460   TestBitrateObserver observer;
461   allocator_->AddObserver(&observer, 30000, 300000, 0, false, "");
462   EXPECT_EQ(300000, allocator_->GetStartBitrate(&observer));
463 
464   allocator_->OnNetworkChanged(30000, 0, 50, kDefaultProbingIntervalMs);
465   EXPECT_EQ(30000u, observer.last_bitrate_bps_);
466 
467   allocator_->OnNetworkChanged(20000, 0, 50, kDefaultProbingIntervalMs);
468   EXPECT_EQ(0u, observer.last_bitrate_bps_);
469 
470   allocator_->OnNetworkChanged(30000, 0, 50, kDefaultProbingIntervalMs);
471   EXPECT_EQ(0u, observer.last_bitrate_bps_);
472 
473   allocator_->OnNetworkChanged(49000, 0, 50, kDefaultProbingIntervalMs);
474   EXPECT_EQ(0u, observer.last_bitrate_bps_);
475 
476   allocator_->OnNetworkChanged(50000, 0, 50, kDefaultProbingIntervalMs);
477   EXPECT_EQ(50000u, observer.last_bitrate_bps_);
478 
479   allocator_->OnNetworkChanged(30000, 0, 50, kDefaultProbingIntervalMs);
480   EXPECT_EQ(30000u, observer.last_bitrate_bps_);
481 
482   allocator_->RemoveObserver(&observer);
483 }
484 
TEST_F(BitrateAllocatorTest,AvoidTogglePercent)485 TEST_F(BitrateAllocatorTest, AvoidTogglePercent) {
486   TestBitrateObserver observer;
487   allocator_->AddObserver(&observer, 300000, 600000, 0, false, "");
488   EXPECT_EQ(300000, allocator_->GetStartBitrate(&observer));
489 
490   allocator_->OnNetworkChanged(300000, 0, 50, kDefaultProbingIntervalMs);
491   EXPECT_EQ(300000u, observer.last_bitrate_bps_);
492 
493   allocator_->OnNetworkChanged(200000, 0, 50, kDefaultProbingIntervalMs);
494   EXPECT_EQ(0u, observer.last_bitrate_bps_);
495 
496   allocator_->OnNetworkChanged(300000, 0, 50, kDefaultProbingIntervalMs);
497   EXPECT_EQ(0u, observer.last_bitrate_bps_);
498 
499   allocator_->OnNetworkChanged(329000, 0, 50, kDefaultProbingIntervalMs);
500   EXPECT_EQ(0u, observer.last_bitrate_bps_);
501 
502   allocator_->OnNetworkChanged(330000, 0, 50, kDefaultProbingIntervalMs);
503   EXPECT_EQ(330000u, observer.last_bitrate_bps_);
504 
505   allocator_->OnNetworkChanged(300000, 0, 50, kDefaultProbingIntervalMs);
506   EXPECT_EQ(300000u, observer.last_bitrate_bps_);
507 
508   allocator_->RemoveObserver(&observer);
509 }
510 
TEST_F(BitrateAllocatorTest,PassProbingInterval)511 TEST_F(BitrateAllocatorTest, PassProbingInterval) {
512   TestBitrateObserver observer;
513   allocator_->AddObserver(&observer, 300000, 600000, 0, false, "");
514   EXPECT_EQ(300000, allocator_->GetStartBitrate(&observer));
515 
516   allocator_->OnNetworkChanged(300000, 0, 50, 5000);
517   EXPECT_EQ(5000, observer.last_probing_interval_ms_);
518 
519   allocator_->RemoveObserver(&observer);
520 }
521 
TEST_F(BitrateAllocatorTest,PriorityRateOneObserverBasic)522 TEST_F(BitrateAllocatorTest, PriorityRateOneObserverBasic) {
523   TestBitrateObserver observer;
524   const uint32_t kMinSendBitrateBps = 10;
525   const uint32_t kMaxSendBitrateBps = 60;
526   const uint32_t kNetworkBandwidthBps = 30;
527 
528   allocator_->AddObserver(&observer, kMinSendBitrateBps, kMaxSendBitrateBps, 0,
529                           true, "", 2.0);
530   allocator_->OnNetworkChanged(kNetworkBandwidthBps, 0, 0,
531                                kDefaultProbingIntervalMs);
532 
533   EXPECT_EQ(kNetworkBandwidthBps, observer.last_bitrate_bps_);
534 
535   allocator_->RemoveObserver(&observer);
536 }
537 
538 // Tests that two observers with the same bitrate priority are allocated
539 // their bitrate evenly.
TEST_F(BitrateAllocatorTest,PriorityRateTwoObserversBasic)540 TEST_F(BitrateAllocatorTest, PriorityRateTwoObserversBasic) {
541   TestBitrateObserver observer_low_1;
542   TestBitrateObserver observer_low_2;
543   const uint32_t kMinSendBitrateBps = 10;
544   const uint32_t kMaxSendBitrateBps = 60;
545   const uint32_t kNetworkBandwidthBps = 60;
546   allocator_->AddObserver(&observer_low_1, kMinSendBitrateBps,
547                           kMaxSendBitrateBps, 0, false, "low1", 2.0);
548   allocator_->AddObserver(&observer_low_2, kMinSendBitrateBps,
549                           kMaxSendBitrateBps, 0, false, "low2", 2.0);
550   allocator_->OnNetworkChanged(kNetworkBandwidthBps, 0, 0,
551                                kDefaultProbingIntervalMs);
552 
553   EXPECT_EQ(kNetworkBandwidthBps / 2, observer_low_1.last_bitrate_bps_);
554   EXPECT_EQ(kNetworkBandwidthBps / 2, observer_low_2.last_bitrate_bps_);
555 
556   allocator_->RemoveObserver(&observer_low_1);
557   allocator_->RemoveObserver(&observer_low_2);
558 }
559 
560 // Tests that there is no difference in functionality when the min bitrate is
561 // enforced.
TEST_F(BitrateAllocatorTest,PriorityRateTwoObserversBasicMinEnforced)562 TEST_F(BitrateAllocatorTest, PriorityRateTwoObserversBasicMinEnforced) {
563   TestBitrateObserver observer_low_1;
564   TestBitrateObserver observer_low_2;
565   const uint32_t kMinSendBitrateBps = 0;
566   const uint32_t kMaxSendBitrateBps = 60;
567   const uint32_t kNetworkBandwidthBps = 60;
568   allocator_->AddObserver(&observer_low_1, kMinSendBitrateBps,
569                           kMaxSendBitrateBps, 0, true, "low1", 2.0);
570   allocator_->AddObserver(&observer_low_2, kMinSendBitrateBps,
571                           kMaxSendBitrateBps, 0, true, "low2", 2.0);
572   allocator_->OnNetworkChanged(kNetworkBandwidthBps, 0, 0,
573                                kDefaultProbingIntervalMs);
574 
575   EXPECT_EQ(kNetworkBandwidthBps / 2, observer_low_1.last_bitrate_bps_);
576   EXPECT_EQ(kNetworkBandwidthBps / 2, observer_low_2.last_bitrate_bps_);
577 
578   allocator_->RemoveObserver(&observer_low_1);
579   allocator_->RemoveObserver(&observer_low_2);
580 }
581 
582 // Tests that if the available bandwidth is the sum of the max bitrate
583 // of all observers, they will be allocated their max.
TEST_F(BitrateAllocatorTest,PriorityRateTwoObserversBothAllocatedMax)584 TEST_F(BitrateAllocatorTest, PriorityRateTwoObserversBothAllocatedMax) {
585   TestBitrateObserver observer_low;
586   TestBitrateObserver observer_mid;
587   const uint32_t kMinSendBitrateBps = 0;
588   const uint32_t kMaxSendBitrateBps = 60;
589   const uint32_t kNetworkBandwidthBps = kMaxSendBitrateBps * 2;
590   allocator_->AddObserver(&observer_low, kMinSendBitrateBps, kMaxSendBitrateBps,
591                           0, true, "low", 2.0);
592   allocator_->AddObserver(&observer_mid, kMinSendBitrateBps, kMaxSendBitrateBps,
593                           0, true, "mid", 4.0);
594   allocator_->OnNetworkChanged(kNetworkBandwidthBps, 0, 0,
595                                kDefaultProbingIntervalMs);
596 
597   EXPECT_EQ(kMaxSendBitrateBps, observer_low.last_bitrate_bps_);
598   EXPECT_EQ(kMaxSendBitrateBps, observer_mid.last_bitrate_bps_);
599 
600   allocator_->RemoveObserver(&observer_low);
601   allocator_->RemoveObserver(&observer_mid);
602 }
603 
604 // Tests that after a higher bitrate priority observer has been allocated its
605 // max bitrate the lower priority observer will then be allocated the remaining
606 // bitrate.
TEST_F(BitrateAllocatorTest,PriorityRateTwoObserversOneAllocatedToMax)607 TEST_F(BitrateAllocatorTest, PriorityRateTwoObserversOneAllocatedToMax) {
608   TestBitrateObserver observer_low;
609   TestBitrateObserver observer_mid;
610   allocator_->AddObserver(&observer_low, 10, 50, 0, false, "low", 2.0);
611   allocator_->AddObserver(&observer_mid, 10, 50, 0, false, "mid", 4.0);
612   allocator_->OnNetworkChanged(90, 0, 0, kDefaultProbingIntervalMs);
613 
614   EXPECT_EQ(40u, observer_low.last_bitrate_bps_);
615   EXPECT_EQ(50u, observer_mid.last_bitrate_bps_);
616 
617   allocator_->RemoveObserver(&observer_low);
618   allocator_->RemoveObserver(&observer_mid);
619 }
620 
621 // Tests that three observers with three different bitrate priorities will all
622 // be allocated bitrate according to their relative bitrate priority.
TEST_F(BitrateAllocatorTest,PriorityRateThreeObserversAllocatedRelativeAmounts)623 TEST_F(BitrateAllocatorTest,
624        PriorityRateThreeObserversAllocatedRelativeAmounts) {
625   TestBitrateObserver observer_low;
626   TestBitrateObserver observer_mid;
627   TestBitrateObserver observer_high;
628   const uint32_t kMaxBitrate = 100;
629   // Not enough bandwidth to fill any observer's max bitrate.
630   const uint32_t kNetworkBandwidthBps = 70;
631   const double kLowBitratePriority = 2.0;
632   const double kMidBitratePriority = 4.0;
633   const double kHighBitratePriority = 8.0;
634   const double kTotalBitratePriority =
635       kLowBitratePriority + kMidBitratePriority + kHighBitratePriority;
636   allocator_->AddObserver(&observer_low, 0, kMaxBitrate, 0, false, "low",
637                           kLowBitratePriority);
638   allocator_->AddObserver(&observer_mid, 0, kMaxBitrate, 0, false, "mid",
639                           kMidBitratePriority);
640   allocator_->AddObserver(&observer_high, 0, kMaxBitrate, 0, false, "high",
641                           kHighBitratePriority);
642   allocator_->OnNetworkChanged(kNetworkBandwidthBps, 0, 0,
643                                kDefaultProbingIntervalMs);
644 
645   const double kLowFractionAllocated =
646       kLowBitratePriority / kTotalBitratePriority;
647   const double kMidFractionAllocated =
648       kMidBitratePriority / kTotalBitratePriority;
649   const double kHighFractionAllocated =
650       kHighBitratePriority / kTotalBitratePriority;
651   EXPECT_EQ(kLowFractionAllocated * kNetworkBandwidthBps,
652             observer_low.last_bitrate_bps_);
653   EXPECT_EQ(kMidFractionAllocated * kNetworkBandwidthBps,
654             observer_mid.last_bitrate_bps_);
655   EXPECT_EQ(kHighFractionAllocated * kNetworkBandwidthBps,
656             observer_high.last_bitrate_bps_);
657 
658   allocator_->RemoveObserver(&observer_low);
659   allocator_->RemoveObserver(&observer_mid);
660   allocator_->RemoveObserver(&observer_high);
661 }
662 
663 // Tests that after the high priority observer has been allocated its maximum
664 // bitrate, the other two observers are still allocated bitrate according to
665 // their relative bitrate priority.
TEST_F(BitrateAllocatorTest,PriorityRateThreeObserversHighAllocatedToMax)666 TEST_F(BitrateAllocatorTest, PriorityRateThreeObserversHighAllocatedToMax) {
667   TestBitrateObserver observer_low;
668   const double kLowBitratePriority = 2.0;
669   TestBitrateObserver observer_mid;
670   const double kMidBitratePriority = 4.0;
671   TestBitrateObserver observer_high;
672   const double kHighBitratePriority = 8.0;
673 
674   const uint32_t kAvailableBitrate = 90;
675   const uint32_t kMaxBitrate = 40;
676   const uint32_t kMinBitrate = 10;
677   // Remaining bitrate after allocating to all mins and knowing that the high
678   // priority observer will have its max bitrate allocated.
679   const uint32_t kRemainingBitrate =
680       kAvailableBitrate - kMaxBitrate - (2 * kMinBitrate);
681 
682   allocator_->AddObserver(&observer_low, kMinBitrate, kMaxBitrate, 0, false,
683                           "low", kLowBitratePriority);
684   allocator_->AddObserver(&observer_mid, kMinBitrate, kMaxBitrate, 0, false,
685                           "mid", kMidBitratePriority);
686   allocator_->AddObserver(&observer_high, kMinBitrate, kMaxBitrate, 0, false,
687                           "high", kHighBitratePriority);
688   allocator_->OnNetworkChanged(kAvailableBitrate, 0, 0,
689                                kDefaultProbingIntervalMs);
690 
691   const double kLowFractionAllocated =
692       kLowBitratePriority / (kLowBitratePriority + kMidBitratePriority);
693   const double kMidFractionAllocated =
694       kMidBitratePriority / (kLowBitratePriority + kMidBitratePriority);
695   EXPECT_EQ(kMinBitrate + (kRemainingBitrate * kLowFractionAllocated),
696             observer_low.last_bitrate_bps_);
697   EXPECT_EQ(kMinBitrate + (kRemainingBitrate * kMidFractionAllocated),
698             observer_mid.last_bitrate_bps_);
699   EXPECT_EQ(40u, observer_high.last_bitrate_bps_);
700 
701   allocator_->RemoveObserver(&observer_low);
702   allocator_->RemoveObserver(&observer_mid);
703   allocator_->RemoveObserver(&observer_high);
704 }
705 
706 // Tests that after the low priority observer has been allocated its maximum
707 // bitrate, the other two observers are still allocated bitrate according to
708 // their relative bitrate priority.
TEST_F(BitrateAllocatorTest,PriorityRateThreeObserversLowAllocatedToMax)709 TEST_F(BitrateAllocatorTest, PriorityRateThreeObserversLowAllocatedToMax) {
710   TestBitrateObserver observer_low;
711   const double kLowBitratePriority = 2.0;
712   const uint32_t kLowMaxBitrate = 10;
713   TestBitrateObserver observer_mid;
714   const double kMidBitratePriority = 4.0;
715   TestBitrateObserver observer_high;
716   const double kHighBitratePriority = 8.0;
717 
718   const uint32_t kMinBitrate = 0;
719   const uint32_t kMaxBitrate = 60;
720   const uint32_t kAvailableBitrate = 100;
721   // Remaining bitrate knowing that the low priority observer is allocated its
722   // max bitrate. We know this because it is allocated 2.0/14.0 (1/7) of the
723   // available bitrate, so 70 bps would be sufficient network bandwidth.
724   const uint32_t kRemainingBitrate = kAvailableBitrate - kLowMaxBitrate;
725 
726   allocator_->AddObserver(&observer_low, kMinBitrate, kLowMaxBitrate, 0, false,
727                           "low", kLowBitratePriority);
728   allocator_->AddObserver(&observer_mid, kMinBitrate, kMaxBitrate, 0, false,
729                           "mid", kMidBitratePriority);
730   allocator_->AddObserver(&observer_high, kMinBitrate, kMaxBitrate, 0, false,
731                           "high", kHighBitratePriority);
732   allocator_->OnNetworkChanged(kAvailableBitrate, 0, 0,
733                                kDefaultProbingIntervalMs);
734 
735   const double kMidFractionAllocated =
736       kMidBitratePriority / (kMidBitratePriority + kHighBitratePriority);
737   const double kHighFractionAllocated =
738       kHighBitratePriority / (kMidBitratePriority + kHighBitratePriority);
739   EXPECT_EQ(kLowMaxBitrate, observer_low.last_bitrate_bps_);
740   EXPECT_EQ(kMinBitrate + (kRemainingBitrate * kMidFractionAllocated),
741             observer_mid.last_bitrate_bps_);
742   EXPECT_EQ(kMinBitrate + (kRemainingBitrate * kHighFractionAllocated),
743             observer_high.last_bitrate_bps_);
744 
745   allocator_->RemoveObserver(&observer_low);
746   allocator_->RemoveObserver(&observer_mid);
747   allocator_->RemoveObserver(&observer_high);
748 }
749 
750 // Tests that after two observers are allocated bitrate to their max, the
751 // the remaining observer is allocated what's left appropriately. This test
752 // handles an edge case where the medium and high observer reach their
753 // "relative" max allocation  at the same time. The high has 40 to allocate
754 // above its min, and the mid has 20 to allocate above its min, which scaled
755 // by their bitrate priority is the same for each.
TEST_F(BitrateAllocatorTest,PriorityRateThreeObserversTwoAllocatedToMax)756 TEST_F(BitrateAllocatorTest, PriorityRateThreeObserversTwoAllocatedToMax) {
757   TestBitrateObserver observer_low;
758   TestBitrateObserver observer_mid;
759   TestBitrateObserver observer_high;
760   allocator_->AddObserver(&observer_low, 10, 40, 0, false, "low", 2.0);
761   // Scaled allocation above the min allocation is the same for these two,
762   // meaning they will get allocated  their max at the same time.
763   // Scaled (target allocation) = (max - min) / bitrate priority
764   allocator_->AddObserver(&observer_mid, 10, 30, 0, false, "mid", 4.0);
765   allocator_->AddObserver(&observer_high, 10, 50, 0, false, "high", 8.0);
766   allocator_->OnNetworkChanged(110, 0, 0, kDefaultProbingIntervalMs);
767 
768   EXPECT_EQ(30u, observer_low.last_bitrate_bps_);
769   EXPECT_EQ(30u, observer_mid.last_bitrate_bps_);
770   EXPECT_EQ(50u, observer_high.last_bitrate_bps_);
771 
772   allocator_->RemoveObserver(&observer_low);
773   allocator_->RemoveObserver(&observer_mid);
774   allocator_->RemoveObserver(&observer_high);
775 }
776 
777 }  // namespace webrtc
778