More gracefully handle rtp timestamp jumps in the rtp to ntp estimator.

webrtc/system_wrappers/source/rtp_to_ntp_estimator_unittest.cc

 /*
  *  Copyright (c) 2012 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.
  */
 
@@ skipping 120 matching lines @@
   EXPECT_TRUE(
       estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
   timestamp -= kTimestampTicksPerMs;
   int64_t timestamp_ms = -1;
   EXPECT_TRUE(estimator.Estimate(timestamp, &timestamp_ms));
   // Constructed at the same time as the first RTCP and should therefore be
   // mapped to zero.
   EXPECT_EQ(0, timestamp_ms);
 }
 
+TEST(WrapAroundTests, GracefullyHandleRtpJump) {
+  RtpToNtpEstimator estimator;
+  bool new_sr;
+  uint32_t ntp_sec = 0;
+  uint32_t ntp_frac = 1;
+  uint32_t timestamp = 0;
+  EXPECT_TRUE(
+      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
+  ntp_frac += kOneMsInNtpFrac;
+  timestamp += kTimestampTicksPerMs;
+  EXPECT_TRUE(
+      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
+  ntp_frac += kOneMsInNtpFrac;
+  timestamp -= kTimestampTicksPerMs;
+  int64_t timestamp_ms = -1;
+  EXPECT_TRUE(estimator.Estimate(timestamp, &timestamp_ms));
+  // Constructed at the same time as the first RTCP and should therefore be
+  // mapped to zero.
+  EXPECT_EQ(0, timestamp_ms);
+
+  timestamp -= 0xFFFFF;
+  for (int i = 0; i < RtpToNtpEstimator::kMaxInvalidSamples - 1; ++i) {
+    EXPECT_FALSE(
+        estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
+    ntp_frac += kOneMsInNtpFrac;
+    timestamp += kTimestampTicksPerMs;
+  }
+  EXPECT_TRUE(
+      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
+  ntp_frac += kOneMsInNtpFrac;
+  timestamp += kTimestampTicksPerMs;
+  EXPECT_TRUE(
+      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
+  ntp_frac += kOneMsInNtpFrac;
+  timestamp += kTimestampTicksPerMs;
+
+  timestamp_ms = -1;
+  EXPECT_TRUE(estimator.Estimate(timestamp, &timestamp_ms));
+  // 6 milliseconds has passed since the start of the test.
+  EXPECT_EQ(6, timestamp_ms);
+}
+
 TEST(UpdateRtcpMeasurementTests, FailsForZeroNtp) {
   RtpToNtpEstimator estimator;
   uint32_t ntp_sec = 0;
   uint32_t ntp_frac = 0;
   uint32_t timestamp = 0x12345678;
   bool new_sr;
   EXPECT_FALSE(
       estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
   EXPECT_FALSE(new_sr);
 }
@@ skipping 92 matching lines @@
   EXPECT_TRUE(
       estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
   EXPECT_TRUE(new_sr);
   // Parameters are not calculated, conversion of RTP to NTP time should fail.
   EXPECT_FALSE(estimator.params().calculated);
   int64_t timestamp_ms = -1;
   EXPECT_FALSE(estimator.Estimate(timestamp, &timestamp_ms));
 }
 
 };  // namespace webrtc