Move webrtc/{base => rtc_base}

webrtc/base/timestampaligner_unittest.cc

Index: webrtc/base/timestampaligner_unittest.cc
diff --git a/webrtc/base/timestampaligner_unittest.cc b/webrtc/base/timestampaligner_unittest.cc
deleted file mode 100644
index a4c0e5a41fc4b8046bd54cd2dd282e8e9ac525d2..0000000000000000000000000000000000000000
--- a/webrtc/base/timestampaligner_unittest.cc
+++ /dev/null
@@ -1,187 +0,0 @@
-/*
- *  Copyright 2016 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 <math.h>
-
-#include <algorithm>
-#include <limits>
-
-#include "webrtc/base/gunit.h"
-#include "webrtc/base/random.h"
-#include "webrtc/base/timestampaligner.h"
-
-namespace rtc {
-
-namespace {
-// Computes the difference x_k - mean(x), when x_k is the linear sequence x_k =
-// k, and the "mean" is plain mean for the first |window_size| samples, followed
-// by exponential averaging with weight 1 / |window_size| for each new sample.
-// This is needed to predict the effect of camera clock drift on the timestamp
-// translation. See the comment on TimestampAligner::UpdateOffset for more
-// context.
-double MeanTimeDifference(int nsamples, int window_size) {
-  if (nsamples <= window_size) {
-    // Plain averaging.
-    return nsamples / 2.0;
-  } else {
-    // Exponential convergence towards
-    // interval_error * (window_size - 1)
-    double alpha = 1.0 - 1.0 / window_size;
-
-    return ((window_size - 1) -
-            (window_size / 2.0 - 1) * pow(alpha, nsamples - window_size));
-  }
-}
-
-class TimestampAlignerForTest : public TimestampAligner {
-  // Make internal methods accessible to testing.
- public:
-  using TimestampAligner::UpdateOffset;
-  using TimestampAligner::ClipTimestamp;
-};
-
-void TestTimestampFilter(double rel_freq_error) {
-  TimestampAlignerForTest timestamp_aligner_for_test;
-  TimestampAligner timestamp_aligner;
-  const int64_t kEpoch = 10000;
-  const int64_t kJitterUs = 5000;
-  const int64_t kIntervalUs = 33333;  // 30 FPS
-  const int kWindowSize = 100;
-  const int kNumFrames = 3 * kWindowSize;
-
-  int64_t interval_error_us = kIntervalUs * rel_freq_error;
-  int64_t system_start_us = rtc::TimeMicros();
-  webrtc::Random random(17);
-
-  int64_t prev_translated_time_us = system_start_us;
-
-  for (int i = 0; i < kNumFrames; i++) {
-    // Camera time subject to drift.
-    int64_t camera_time_us = kEpoch + i * (kIntervalUs + interval_error_us);
-    int64_t system_time_us = system_start_us + i * kIntervalUs;
-    // And system time readings are subject to jitter.
-    int64_t system_measured_us = system_time_us + random.Rand(kJitterUs);
-
-    int64_t offset_us = timestamp_aligner_for_test.UpdateOffset(
-        camera_time_us, system_measured_us);
-
-    int64_t filtered_time_us = camera_time_us + offset_us;
-    int64_t translated_time_us = timestamp_aligner_for_test.ClipTimestamp(
-        filtered_time_us, system_measured_us);
-
-    // Check that we get identical result from the all-in-one helper method.
-    ASSERT_EQ(translated_time_us, timestamp_aligner.TranslateTimestamp(
-                                      camera_time_us, system_measured_us));
-
-    EXPECT_LE(translated_time_us, system_measured_us);
-    EXPECT_GE(translated_time_us,
-              prev_translated_time_us + rtc::kNumMicrosecsPerMillisec);
-
-    // The relative frequency error contributes to the expected error
-    // by a factor which is the difference between the current time
-    // and the average of earlier sample times.
-    int64_t expected_error_us =
-        kJitterUs / 2 +
-        rel_freq_error * kIntervalUs * MeanTimeDifference(i, kWindowSize);
-
-    int64_t bias_us = filtered_time_us - translated_time_us;
-    EXPECT_GE(bias_us, 0);
-
-    if (i == 0) {
-      EXPECT_EQ(translated_time_us, system_measured_us);
-    } else {
-      EXPECT_NEAR(filtered_time_us, system_time_us + expected_error_us,
-                  2.0 * kJitterUs / sqrt(std::max(i, kWindowSize)));
-    }
-    // If the camera clock runs too fast (rel_freq_error > 0.0), The
-    // bias is expected to roughly cancel the expected error from the
-    // clock drift, as this grows. Otherwise, it reflects the
-    // measurement noise. The tolerances here were selected after some
-    // trial and error.
-    if (i < 10 || rel_freq_error <= 0.0) {
-      EXPECT_LE(bias_us, 3000);
-    } else {
-      EXPECT_NEAR(bias_us, expected_error_us, 1500);
-    }
-    prev_translated_time_us = translated_time_us;
-  }
-}
-
-}  // Anonymous namespace
-
-TEST(TimestampAlignerTest, AttenuateTimestampJitterNoDrift) {
-  TestTimestampFilter(0.0);
-}
-
-// 100 ppm is a worst case for a reasonable crystal.
-TEST(TimestampAlignerTest, AttenuateTimestampJitterSmallPosDrift) {
-  TestTimestampFilter(0.0001);
-}
-
-TEST(TimestampAlignerTest, AttenuateTimestampJitterSmallNegDrift) {
-  TestTimestampFilter(-0.0001);
-}
-
-// 3000 ppm, 3 ms / s, is the worst observed drift, see
-// https://bugs.chromium.org/p/webrtc/issues/detail?id=5456
-TEST(TimestampAlignerTest, AttenuateTimestampJitterLargePosDrift) {
-  TestTimestampFilter(0.003);
-}
-
-TEST(TimestampAlignerTest, AttenuateTimestampJitterLargeNegDrift) {
-  TestTimestampFilter(-0.003);
-}
-
-// Exhibits a mostly hypothetical problem, where certain inputs to the
-// TimestampAligner.UpdateOffset filter result in non-monotonous
-// translated timestamps. This test verifies that the ClipTimestamp
-// logic handles this case correctly.
-TEST(TimestampAlignerTest, ClipToMonotonous) {
-  TimestampAlignerForTest timestamp_aligner;
-
-  // For system time stamps { 0, s1, s1 + s2 }, and camera timestamps
-  // {0, c1, c1 + c2}, we exhibit non-monotonous behaviour if and only
-  // if c1 > s1 + 2 s2 + 4 c2.
-  const int kNumSamples = 3;
-  const int64_t camera_time_us[kNumSamples] = {0, 80000, 90001};
-  const int64_t system_time_us[kNumSamples] = {0, 10000, 20000};
-  const int64_t expected_offset_us[kNumSamples] = {0, -35000, -46667};
-
-  // Non-monotonic translated timestamps can happen when only for
-  // translated timestamps in the future. Which is tolerated if
-  // |timestamp_aligner.clip_bias_us| is large enough. Instead of
-  // changing that private member for this test, just add the bias to
-  // |system_time_us| when calling ClipTimestamp.
-  const int64_t kClipBiasUs = 100000;
-
-  bool did_clip = false;
-  int64_t prev_timestamp_us = std::numeric_limits<int64_t>::min();
-  for (int i = 0; i < kNumSamples; i++) {
-    int64_t offset_us =
-        timestamp_aligner.UpdateOffset(camera_time_us[i], system_time_us[i]);
-    EXPECT_EQ(offset_us, expected_offset_us[i]);
-
-    int64_t translated_timestamp_us = camera_time_us[i] + offset_us;
-    int64_t clip_timestamp_us = timestamp_aligner.ClipTimestamp(
-        translated_timestamp_us, system_time_us[i] + kClipBiasUs);
-    if (translated_timestamp_us <= prev_timestamp_us) {
-      did_clip = true;
-      EXPECT_EQ(clip_timestamp_us,
-                prev_timestamp_us + rtc::kNumMicrosecsPerMillisec);
-    } else {
-      // No change from clipping.
-      EXPECT_EQ(clip_timestamp_us, translated_timestamp_us);
-    }
-    prev_timestamp_us = clip_timestamp_us;
-  }
-  EXPECT_TRUE(did_clip);
-}
-
-}  // namespace rtc