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
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/memory/scoped_ptr.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/stringprintf.h"
#include "media/filters/video_cadence_estimator.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace media {
// See VideoCadenceEstimator header for more details.
const int kMinimumAcceptableTimeBetweenGlitchesSecs = 8;
// Slows down the given |fps| according to NTSC field reduction standards; see
// http://en.wikipedia.org/wiki/Frame_rate#Digital_video_and_television
static double NTSC(double fps) {
return fps / 1.001;
}
static base::TimeDelta Interval(double hertz) {
return base::TimeDelta::FromSecondsD(1.0 / hertz);
}
std::vector<int> CreateCadenceFromString(const std::string& cadence) {
CHECK_EQ('[', cadence[0]);
CHECK_EQ(']', cadence[cadence.length() - 1]);
std::vector<int> result;
for (const std::string& token :
base::SplitString(cadence.substr(1, cadence.length() - 2),
":", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL)) {
int cadence_value = 0;
CHECK(base::StringToInt(token, &cadence_value)) << token;
result.push_back(cadence_value);
}
return result;
}
static void VerifyCadenceVector(VideoCadenceEstimator* estimator,
double frame_hertz,
double render_hertz,
const std::string& expected_cadence) {
SCOPED_TRACE(base::StringPrintf("Checking %.03f fps into %0.03f", frame_hertz,
render_hertz));
const std::vector<int> expected_cadence_vector =
CreateCadenceFromString(expected_cadence);
estimator->Reset();
const base::TimeDelta acceptable_drift = std::max(Interval(frame_hertz) / 2,
Interval(render_hertz));
const bool cadence_changed = estimator->UpdateCadenceEstimate(
Interval(render_hertz), Interval(frame_hertz), acceptable_drift);
EXPECT_EQ(cadence_changed, estimator->has_cadence());
EXPECT_EQ(expected_cadence_vector.empty(), !estimator->has_cadence());
// Nothing further to test.
if (expected_cadence_vector.empty() || !estimator->has_cadence())
return;
EXPECT_EQ(expected_cadence_vector.size(),
estimator->cadence_size_for_testing());
// Spot two cycles of the cadence.
for (size_t i = 0; i < expected_cadence_vector.size() * 2; ++i) {
ASSERT_EQ(expected_cadence_vector[i % expected_cadence_vector.size()],
estimator->GetCadenceForFrame(i));
}
}
// Spot check common display and frame rate pairs for correctness.
TEST(VideoCadenceEstimatorTest, CadenceCalculations) {
VideoCadenceEstimator estimator(
base::TimeDelta::FromSeconds(kMinimumAcceptableTimeBetweenGlitchesSecs));
estimator.set_cadence_hysteresis_threshold_for_testing(base::TimeDelta());
const std::string kEmptyCadence = "[]";
VerifyCadenceVector(&estimator, 1, NTSC(60), "[60]");
VerifyCadenceVector(&estimator, 24, 60, "[3:2]");
VerifyCadenceVector(&estimator, NTSC(24), 60, "[3:2]");
VerifyCadenceVector(&estimator, 24, NTSC(60), "[3:2]");
VerifyCadenceVector(&estimator, 25, 60, "[2:3:2:3:2]");
VerifyCadenceVector(&estimator, NTSC(25), 60, "[2:3:2:3:2]");
VerifyCadenceVector(&estimator, 25, NTSC(60), "[2:3:2:3:2]");
VerifyCadenceVector(&estimator, 30, 60, "[2]");
VerifyCadenceVector(&estimator, NTSC(30), 60, "[2]");
VerifyCadenceVector(&estimator, 29.5, 60, kEmptyCadence);
VerifyCadenceVector(&estimator, 50, 60, "[1:1:2:1:1]");
VerifyCadenceVector(&estimator, NTSC(50), 60, "[1:1:2:1:1]");
VerifyCadenceVector(&estimator, 50, NTSC(60), "[1:1:2:1:1]");
VerifyCadenceVector(&estimator, NTSC(60), 60, "[1]");
VerifyCadenceVector(&estimator, 60, NTSC(60), "[1]");
VerifyCadenceVector(&estimator, 120, 60, "[1:0]");
VerifyCadenceVector(&estimator, NTSC(120), 60, "[1:0]");
VerifyCadenceVector(&estimator, 120, NTSC(60), "[1:0]");
// Test cases for cadence below 1.
VerifyCadenceVector(&estimator, 120, 24, "[1:0:0:0:0]");
VerifyCadenceVector(&estimator, 120, 48, "[1:0:0:1:0]");
VerifyCadenceVector(&estimator, 120, 72, "[1:0:1:0:1]");
VerifyCadenceVector(&estimator, 90, 60, "[1:0:1]");
// 50Hz is common in the EU.
VerifyCadenceVector(&estimator, NTSC(24), 50, kEmptyCadence);
VerifyCadenceVector(&estimator, 24, 50, kEmptyCadence);
VerifyCadenceVector(&estimator, NTSC(25), 50, "[2]");
VerifyCadenceVector(&estimator, 25, 50, "[2]");
VerifyCadenceVector(&estimator, NTSC(30), 50, "[2:1:2]");
VerifyCadenceVector(&estimator, 30, 50, "[2:1:2]");
VerifyCadenceVector(&estimator, NTSC(60), 50, kEmptyCadence);
VerifyCadenceVector(&estimator, 60, 50, kEmptyCadence);
}
TEST(VideoCadenceEstimatorTest, CadenceVariesWithAcceptableDrift) {
VideoCadenceEstimator estimator(
base::TimeDelta::FromSeconds(kMinimumAcceptableTimeBetweenGlitchesSecs));
estimator.set_cadence_hysteresis_threshold_for_testing(base::TimeDelta());
const base::TimeDelta render_interval = Interval(NTSC(60));
const base::TimeDelta frame_interval = Interval(120);
base::TimeDelta acceptable_drift = frame_interval / 2;
EXPECT_FALSE(estimator.UpdateCadenceEstimate(render_interval, frame_interval,
acceptable_drift));
EXPECT_FALSE(estimator.has_cadence());
// Increasing the acceptable drift should be result in more permissive
// detection of cadence.
acceptable_drift = render_interval;
EXPECT_TRUE(estimator.UpdateCadenceEstimate(render_interval, frame_interval,
acceptable_drift));
EXPECT_TRUE(estimator.has_cadence());
EXPECT_EQ("[1:0]", estimator.GetCadenceForTesting());
}
TEST(VideoCadenceEstimatorTest, CadenceVariesWithAcceptableGlitchTime) {
scoped_ptr<VideoCadenceEstimator> estimator(new VideoCadenceEstimator(
base::TimeDelta::FromSeconds(kMinimumAcceptableTimeBetweenGlitchesSecs)));
estimator->set_cadence_hysteresis_threshold_for_testing(base::TimeDelta());
const base::TimeDelta render_interval = Interval(NTSC(60));
const base::TimeDelta frame_interval = Interval(120);
const base::TimeDelta acceptable_drift = frame_interval / 2;
EXPECT_FALSE(estimator->UpdateCadenceEstimate(render_interval, frame_interval,
acceptable_drift));
EXPECT_FALSE(estimator->has_cadence());
// Decreasing the acceptable glitch time should be result in more permissive
// detection of cadence.
estimator.reset(new VideoCadenceEstimator(base::TimeDelta::FromSeconds(
kMinimumAcceptableTimeBetweenGlitchesSecs / 2)));
estimator->set_cadence_hysteresis_threshold_for_testing(base::TimeDelta());
EXPECT_TRUE(estimator->UpdateCadenceEstimate(render_interval, frame_interval,
acceptable_drift));
EXPECT_TRUE(estimator->has_cadence());
EXPECT_EQ("[1:0]", estimator->GetCadenceForTesting());
}
TEST(VideoCadenceEstimatorTest, CadenceHystersisPreventsOscillation) {
scoped_ptr<VideoCadenceEstimator> estimator(new VideoCadenceEstimator(
base::TimeDelta::FromSeconds(kMinimumAcceptableTimeBetweenGlitchesSecs)));
const base::TimeDelta render_interval = Interval(30);
const base::TimeDelta frame_interval = Interval(60);
const base::TimeDelta acceptable_drift = frame_interval / 2;
estimator->set_cadence_hysteresis_threshold_for_testing(render_interval * 2);
// Cadence hysteresis should prevent the cadence from taking effect yet.
EXPECT_FALSE(estimator->UpdateCadenceEstimate(render_interval, frame_interval,
acceptable_drift));
EXPECT_FALSE(estimator->has_cadence());
// A second call should exceed cadence hysteresis and take into effect.
EXPECT_TRUE(estimator->UpdateCadenceEstimate(render_interval, frame_interval,
acceptable_drift));
EXPECT_TRUE(estimator->has_cadence());
// One bad interval shouldn't cause cadence to drop
EXPECT_FALSE(estimator->UpdateCadenceEstimate(
render_interval, frame_interval * 0.75, acceptable_drift));
EXPECT_TRUE(estimator->has_cadence());
// Resumption of cadence should clear bad interval count.
EXPECT_FALSE(estimator->UpdateCadenceEstimate(render_interval, frame_interval,
acceptable_drift));
EXPECT_TRUE(estimator->has_cadence());
// So one more bad interval shouldn't cause cadence to drop
EXPECT_FALSE(estimator->UpdateCadenceEstimate(
render_interval, frame_interval * 0.75, acceptable_drift));
EXPECT_TRUE(estimator->has_cadence());
// Two bad intervals should.
EXPECT_TRUE(estimator->UpdateCadenceEstimate(
render_interval, frame_interval * 0.75, acceptable_drift));
EXPECT_FALSE(estimator->has_cadence());
}
} // namespace media
|
