1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
/*
* Copyright (c) 2022 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.
*/
#include "modules/video_coding/timing/inter_frame_delay_variation_calculator.h"
#include <limits>
#include "absl/types/optional.h"
#include "api/units/frequency.h"
#include "api/units/time_delta.h"
#include "api/units/timestamp.h"
#include "system_wrappers/include/clock.h"
#include "test/gmock.h"
#include "test/gtest.h"
namespace webrtc {
namespace {
// Test is for frames at 30fps. At 30fps, RTP timestamps will increase by
// 90000 / 30 = 3000 ticks per frame.
constexpr Frequency k30Fps = Frequency::Hertz(30);
constexpr TimeDelta kFrameDelay = 1 / k30Fps;
constexpr uint32_t kRtpTicksPerFrame = Frequency::KiloHertz(90) / k30Fps;
constexpr Timestamp kStartTime = Timestamp::Millis(1337);
} // namespace
using ::testing::Eq;
using ::testing::Optional;
TEST(InterFrameDelayVariationCalculatorTest, OldRtpTimestamp) {
InterFrameDelayVariationCalculator ifdv_calculator;
EXPECT_THAT(ifdv_calculator.Calculate(180000, kStartTime),
Optional(TimeDelta::Zero()));
EXPECT_THAT(ifdv_calculator.Calculate(90000, kStartTime), Eq(absl::nullopt));
}
TEST(InterFrameDelayVariationCalculatorTest,
NegativeWrapAroundIsSameAsOldRtpTimestamp) {
InterFrameDelayVariationCalculator ifdv_calculator;
uint32_t rtp = 1500;
EXPECT_THAT(ifdv_calculator.Calculate(rtp, kStartTime),
Optional(TimeDelta::Zero()));
// RTP has wrapped around backwards.
rtp -= 3000;
EXPECT_THAT(ifdv_calculator.Calculate(rtp, kStartTime), Eq(absl::nullopt));
}
TEST(InterFrameDelayVariationCalculatorTest, CorrectDelayForFrames) {
InterFrameDelayVariationCalculator ifdv_calculator;
// Use a fake clock to simplify time keeping.
SimulatedClock clock(kStartTime);
// First frame is always delay variation 0.
uint32_t rtp = 90000;
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(TimeDelta::Zero()));
// Perfectly timed frame has 0 delay variation.
clock.AdvanceTime(kFrameDelay);
rtp += kRtpTicksPerFrame;
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(TimeDelta::Zero()));
// Slightly early frame will have a negative delay variation.
clock.AdvanceTime(kFrameDelay - TimeDelta::Millis(3));
rtp += kRtpTicksPerFrame;
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(-TimeDelta::Millis(3)));
// Slightly late frame will have positive delay variation.
clock.AdvanceTime(kFrameDelay + TimeDelta::Micros(5125));
rtp += kRtpTicksPerFrame;
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(TimeDelta::Micros(5125)));
// Simulate faster frame RTP at the same clock delay. The frame arrives late,
// since the RTP timestamp is faster than the delay, and thus is positive.
clock.AdvanceTime(kFrameDelay);
rtp += kRtpTicksPerFrame / 2;
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(kFrameDelay / 2.0));
// Simulate slower frame RTP at the same clock delay. The frame is early,
// since the RTP timestamp advanced more than the delay, and thus is negative.
clock.AdvanceTime(kFrameDelay);
rtp += 1.5 * kRtpTicksPerFrame;
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(-kFrameDelay / 2.0));
}
TEST(InterFrameDelayVariationCalculatorTest, PositiveWrapAround) {
InterFrameDelayVariationCalculator ifdv_calculator;
// Use a fake clock to simplify time keeping.
SimulatedClock clock(kStartTime);
// First frame is behind the max RTP by 1500.
uint32_t rtp = std::numeric_limits<uint32_t>::max() - 1500;
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(TimeDelta::Zero()));
// Rtp wraps around, now 1499.
rtp += kRtpTicksPerFrame;
// Frame delay should be as normal, in this case simulated as 1ms late.
clock.AdvanceTime(kFrameDelay + TimeDelta::Millis(1));
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(TimeDelta::Millis(1)));
}
TEST(InterFrameDelayVariationCalculatorTest, MultipleWrapArounds) {
// Simulate a long pauses which cause wrap arounds multiple times.
constexpr Frequency k90Khz = Frequency::KiloHertz(90);
constexpr uint32_t kHalfRtp = std::numeric_limits<uint32_t>::max() / 2;
constexpr TimeDelta kWrapAroundDelay = kHalfRtp / k90Khz;
InterFrameDelayVariationCalculator ifdv_calculator;
// Use a fake clock to simplify time keeping.
SimulatedClock clock(kStartTime);
uint32_t rtp = 0;
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(TimeDelta::Zero()));
rtp += kHalfRtp;
clock.AdvanceTime(kWrapAroundDelay);
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(TimeDelta::Zero()));
// 1st wrap around.
rtp += kHalfRtp + 1;
clock.AdvanceTime(kWrapAroundDelay + TimeDelta::Millis(1));
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(TimeDelta::Millis(1) - (1 / k90Khz)));
rtp += kHalfRtp;
clock.AdvanceTime(kWrapAroundDelay);
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(TimeDelta::Zero()));
// 2nd wrap arounds.
rtp += kHalfRtp + 1;
clock.AdvanceTime(kWrapAroundDelay - TimeDelta::Millis(1));
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(-TimeDelta::Millis(1) - (1 / k90Khz)));
// Ensure short delay (large RTP delay) between wrap-arounds has correct
// jitter.
rtp += kHalfRtp;
clock.AdvanceTime(TimeDelta::Millis(10));
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(-(kWrapAroundDelay - TimeDelta::Millis(10))));
// 3nd wrap arounds, this time with large RTP delay.
rtp += kHalfRtp + 1;
clock.AdvanceTime(TimeDelta::Millis(10));
EXPECT_THAT(
ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(-(kWrapAroundDelay - TimeDelta::Millis(10) + (1 / k90Khz))));
}
TEST(InterFrameDelayVariationCalculatorTest,
NegativeWrapAroundAfterPositiveWrapAround) {
InterFrameDelayVariationCalculator ifdv_calculator;
// Use a fake clock to simplify time keeping.
SimulatedClock clock(kStartTime);
uint32_t rtp = std::numeric_limits<uint32_t>::max() - 1500;
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(TimeDelta::Zero()));
// Rtp wraps around, now 1499.
rtp += kRtpTicksPerFrame;
// Frame delay should be as normal, in this case simulated as 1ms late.
clock.AdvanceTime(kFrameDelay);
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Optional(TimeDelta::Zero()));
// Wrap back.
rtp -= kRtpTicksPerFrame;
// Frame delay should be as normal, in this case simulated as 1ms late.
clock.AdvanceTime(kFrameDelay);
EXPECT_THAT(ifdv_calculator.Calculate(rtp, clock.CurrentTime()),
Eq(absl::nullopt));
}
} // namespace webrtc
|