Move the capture ntp computing code to ntp_calculator so that later it can be shared with voe.

BUG=3111
TEST=try bots
R=stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/13489004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6152 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/modules.gyp

@@ -199,6 +199,7 @@
             'rtp_rtcp/source/nack_rtx_unittest.cc',
             'rtp_rtcp/source/producer_fec_unittest.cc',
             'rtp_rtcp/source/receive_statistics_unittest.cc',
+            'rtp_rtcp/source/remote_ntp_time_estimator_unittest.cc',
             'rtp_rtcp/source/rtcp_format_remb_unittest.cc',
             'rtp_rtcp/source/rtcp_packet_unittest.cc',
             'rtp_rtcp/source/rtcp_receiver_unittest.cc',

webrtc/modules/rtp_rtcp/interface/remote_ntp_time_estimator.h

@@ -0,0 +1,50 @@
+/*
+ *  Copyright (c) 2014 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.
+ */
+
+#ifndef WEBRTC_MODULES_RTP_RTCP_INTERFACE_REMOTE_NTP_TIME_ESTIMATOR_H_
+#define WEBRTC_MODULES_RTP_RTCP_INTERFACE_REMOTE_NTP_TIME_ESTIMATOR_H_
+
+#include "webrtc/system_wrappers/interface/rtp_to_ntp.h"
+#include "webrtc/system_wrappers/interface/scoped_ptr.h"
+
+namespace webrtc {
+
+class Clock;
+class RtpRtcp;
+class TimestampExtrapolator;
+
+// RemoteNtpTimeEstimator can be used to estimate a given RTP timestamp's NTP
+// time in local timebase.
+// Note that it needs to be trained with at least 2 RTCP SR (by calling
+// |UpdateRtcpTimestamp|) before it can be used.
+class RemoteNtpTimeEstimator {
+ public:
+  explicit RemoteNtpTimeEstimator(Clock* clock);
+
+  ~RemoteNtpTimeEstimator();
+
+  // Updates the estimator with the timestamp from newly received RTCP SR for
+  // |ssrc|. The RTCP SR is read from |rtp_rtcp|.
+  bool UpdateRtcpTimestamp(uint32_t ssrc, RtpRtcp* rtp_rtcp);
+
+  // Estimates the NTP timestamp in local timebase from |rtp_timestamp|.
+  // Returns the NTP timestamp in ms when success. -1 if failed.
+  int64_t Estimate(uint32_t rtp_timestamp);
+
+ private:
+  Clock* clock_;
+  scoped_ptr<TimestampExtrapolator> ts_extrapolator_;
+  RtcpList rtcp_list_;
+  DISALLOW_COPY_AND_ASSIGN(RemoteNtpTimeEstimator);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_RTP_RTCP_INTERFACE_REMOTE_NTP_TIME_ESTIMATOR_H_

webrtc/modules/rtp_rtcp/source/remote_ntp_time_estimator.cc

@@ -0,0 +1,85 @@
+/*
+ *  Copyright (c) 2014 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 "webrtc/modules/rtp_rtcp/interface/remote_ntp_time_estimator.h"
+
+#include "webrtc/modules/rtp_rtcp/interface/rtp_rtcp.h"
+#include "webrtc/system_wrappers/interface/clock.h"
+#include "webrtc/system_wrappers/interface/timestamp_extrapolator.h"
+
+namespace webrtc {
+
+// TODO(wu): Refactor this class so that it can be shared with
+// vie_sync_module.cc.
+RemoteNtpTimeEstimator::RemoteNtpTimeEstimator(Clock* clock)
+    : clock_(clock),
+      ts_extrapolator_(
+          new TimestampExtrapolator(clock_->TimeInMilliseconds())) {
+}
+
+RemoteNtpTimeEstimator::~RemoteNtpTimeEstimator() {}
+
+bool RemoteNtpTimeEstimator::UpdateRtcpTimestamp(uint32_t ssrc,
+                                                 RtpRtcp* rtp_rtcp) {
+  assert(rtp_rtcp);
+  uint16_t rtt = 0;
+  rtp_rtcp->RTT(ssrc, &rtt, NULL, NULL, NULL);
+  if (rtt == 0) {
+    // Waiting for valid rtt.
+    return true;
+  }
+  // Update RTCP list
+  uint32_t ntp_secs = 0;
+  uint32_t ntp_frac = 0;
+  uint32_t rtp_timestamp = 0;
+  if (0 != rtp_rtcp->RemoteNTP(&ntp_secs,
+                               &ntp_frac,
+                               NULL,
+                               NULL,
+                               &rtp_timestamp)) {
+    // Waiting for RTCP.
+    return true;
+  }
+  bool new_rtcp_sr = false;
+  if (!UpdateRtcpList(
+      ntp_secs, ntp_frac, rtp_timestamp, &rtcp_list_, &new_rtcp_sr)) {
+    return false;
+  }
+  if (!new_rtcp_sr) {
+    // No new RTCP SR since last time this function was called.
+    return true;
+  }
+  // Update extrapolator with the new arrival time.
+  // The extrapolator assumes the TimeInMilliseconds time.
+  int64_t receiver_arrival_time_ms = clock_->TimeInMilliseconds();
+  int64_t sender_send_time_ms = Clock::NtpToMs(ntp_secs, ntp_frac);
+  int64_t sender_arrival_time_90k = (sender_send_time_ms + rtt / 2) * 90;
+  ts_extrapolator_->Update(receiver_arrival_time_ms, sender_arrival_time_90k);
+  return true;
+}
+
+int64_t RemoteNtpTimeEstimator::Estimate(uint32_t rtp_timestamp) {
+  if (rtcp_list_.size() < 2) {
+    // We need two RTCP SR reports to calculate NTP.
+    return -1;
+  }
+  int64_t sender_capture_ntp_ms = 0;
+  if (!RtpToNtpMs(rtp_timestamp, rtcp_list_, &sender_capture_ntp_ms)) {
+    return -1;
+  }
+  uint32_t timestamp = sender_capture_ntp_ms * 90;
+  int64_t receiver_capture_ms =
+      ts_extrapolator_->ExtrapolateLocalTime(timestamp);
+  int64_t ntp_offset =
+      clock_->CurrentNtpInMilliseconds() - clock_->TimeInMilliseconds();
+  return receiver_capture_ms + ntp_offset;
+}
+
+}  // namespace webrtc

webrtc/modules/rtp_rtcp/source/remote_ntp_time_estimator_unittest.cc

@@ -0,0 +1,112 @@
+/*
+*  Copyright (c) 2014 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 "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/common_types.h"
+#include "webrtc/modules/rtp_rtcp/interface/remote_ntp_time_estimator.h"
+#include "webrtc/modules/rtp_rtcp/mocks/mock_rtp_rtcp.h"
+
+using ::testing::_;
+using ::testing::DoAll;
+using ::testing::Return;
+using ::testing::SetArgPointee;
+
+namespace webrtc {
+
+static const int kTestRtt = 10;
+static const int64_t kLocalClockInitialTimeMs = 123;
+static const int64_t kRemoteClockInitialTimeMs = 345;
+static const uint32_t kTimestampOffset = 567;
+static const int kTestSsrc = 789;
+
+class RemoteNtpTimeEstimatorTest : public ::testing::Test {
+ protected:
+  RemoteNtpTimeEstimatorTest()
+      : local_clock_(kLocalClockInitialTimeMs * 1000),
+        remote_clock_(kRemoteClockInitialTimeMs * 1000),
+        estimator_(&local_clock_) {}
+  ~RemoteNtpTimeEstimatorTest() {}
+
+  void AdvanceTimeMilliseconds(int64_t ms) {
+    local_clock_.AdvanceTimeMilliseconds(ms);
+    remote_clock_.AdvanceTimeMilliseconds(ms);
+  }
+
+  uint32_t GetRemoteTimestamp() {
+    return static_cast<uint32_t>(remote_clock_.TimeInMilliseconds()) * 90 +
+           kTimestampOffset;
+  }
+
+  void SendRtcpSr() {
+    uint32_t rtcp_timestamp = GetRemoteTimestamp();
+    uint32_t ntp_seconds;
+    uint32_t ntp_fractions;
+    remote_clock_.CurrentNtp(ntp_seconds, ntp_fractions);
+
+    AdvanceTimeMilliseconds(kTestRtt / 2);
+    ReceiveRtcpSr(rtcp_timestamp, ntp_seconds, ntp_fractions);
+  }
+
+  void UpdateRtcpTimestamp(MockRtpRtcp* rtp_rtcp, bool expected_result) {
+    if (rtp_rtcp) {
+      EXPECT_CALL(*rtp_rtcp, RTT(_, _, _, _, _))
+          .WillOnce(DoAll(SetArgPointee<1>(kTestRtt),
+                          Return(0)));
+    }
+    EXPECT_EQ(expected_result,
+              estimator_.UpdateRtcpTimestamp(kTestSsrc, rtp_rtcp));
+  }
+
+  void ReceiveRtcpSr(uint32_t rtcp_timestamp,
+                     uint32_t ntp_seconds,
+                     uint32_t ntp_fractions) {
+    EXPECT_CALL(rtp_rtcp_, RemoteNTP(_, _, _, _, _))
+        .WillOnce(DoAll(SetArgPointee<0>(ntp_seconds),
+                        SetArgPointee<1>(ntp_fractions),
+                        SetArgPointee<4>(rtcp_timestamp),
+                        Return(0)));
+
+    UpdateRtcpTimestamp(&rtp_rtcp_, true);
+  }
+
+  SimulatedClock local_clock_;
+  SimulatedClock remote_clock_;
+  MockRtpRtcp rtp_rtcp_;
+  RemoteNtpTimeEstimator estimator_;
+};
+
+TEST_F(RemoteNtpTimeEstimatorTest, Estimate) {
+  // Failed without any RTCP SR, where RemoteNTP returns without valid NTP.
+  EXPECT_CALL(rtp_rtcp_, RemoteNTP(_, _, _, _, _)).WillOnce(Return(0));
+  UpdateRtcpTimestamp(&rtp_rtcp_, false);
+
+  AdvanceTimeMilliseconds(1000);
+  // Remote peer sends first RTCP SR.
+  SendRtcpSr();
+
+  // Remote sends a RTP packet.
+  AdvanceTimeMilliseconds(15);
+  uint32_t rtp_timestamp = GetRemoteTimestamp();
+  int64_t capture_ntp_time_ms = local_clock_.CurrentNtpInMilliseconds();
+
+  // Local peer needs at least 2 RTCP SR to calculate the capture time.
+  const int64_t kNotEnoughRtcpSr = -1;
+  EXPECT_EQ(kNotEnoughRtcpSr, estimator_.Estimate(rtp_timestamp));
+
+  AdvanceTimeMilliseconds(800);
+  // Remote sends second RTCP SR.
+  SendRtcpSr();
+
+  // Local peer gets enough RTCP SR to calculate the capture time.
+  EXPECT_EQ(capture_ntp_time_ms, estimator_.Estimate(rtp_timestamp));
+}
+
+}  // namespace webrtc

webrtc/modules/rtp_rtcp/source/rtp_rtcp.gypi

@@ -20,6 +20,7 @@
         # Common
         '../interface/fec_receiver.h',
         '../interface/receive_statistics.h',
+        '../interface/remote_ntp_time_estimator.h',
         '../interface/rtp_header_parser.h',
         '../interface/rtp_payload_registry.h',
         '../interface/rtp_receiver.h',
@@ -32,6 +33,7 @@
         'fec_receiver_impl.h',
         'receive_statistics_impl.cc',
         'receive_statistics_impl.h',
+        'remote_ntp_time_estimator.cc',
         'rtp_header_parser.cc',
         'rtp_rtcp_config.h',
         'rtp_rtcp_impl.cc',

webrtc/video_engine/vie_receiver.cc

@@ -15,6 +15,7 @@
 #include "webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h"
 #include "webrtc/modules/rtp_rtcp/interface/fec_receiver.h"
 #include "webrtc/modules/rtp_rtcp/interface/receive_statistics.h"
+#include "webrtc/modules/rtp_rtcp/interface/remote_ntp_time_estimator.h"
 #include "webrtc/modules/rtp_rtcp/interface/rtp_header_parser.h"
 #include "webrtc/modules/rtp_rtcp/interface/rtp_payload_registry.h"
 #include "webrtc/modules/rtp_rtcp/interface/rtp_receiver.h"
@@ -25,6 +26,7 @@
 #include "webrtc/system_wrappers/interface/logging.h"
 #include "webrtc/system_wrappers/interface/tick_util.h"
 #include "webrtc/system_wrappers/interface/timestamp_extrapolator.h"
+#include "webrtc/system_wrappers/interface/trace.h"
 
 namespace webrtc {
 
@@ -45,9 +47,7 @@ ViEReceiver::ViEReceiver(const int32_t channel_id,
       rtp_rtcp_(NULL),
       vcm_(module_vcm),
       remote_bitrate_estimator_(remote_bitrate_estimator),
-      clock_(Clock::GetRealTimeClock()),
-      ts_extrapolator_(
-          new TimestampExtrapolator(clock_->TimeInMilliseconds())),
+      ntp_estimator_(new RemoteNtpTimeEstimator(Clock::GetRealTimeClock())),
       rtp_dump_(NULL),
       receiving_(false),
       restored_packet_in_use_(false),
@@ -175,7 +175,8 @@ int32_t ViEReceiver::OnReceivedPayloadData(
     const uint8_t* payload_data, const uint16_t payload_size,
     const WebRtcRTPHeader* rtp_header) {
   WebRtcRTPHeader rtp_header_with_ntp = *rtp_header;
-  CalculateCaptureNtpTime(&rtp_header_with_ntp);
+  rtp_header_with_ntp.ntp_time_ms =
+      ntp_estimator_->Estimate(rtp_header->header.timestamp);
   if (vcm_->IncomingPacket(payload_data,
                            payload_size,
                            rtp_header_with_ntp) != 0) {
@@ -185,26 +186,6 @@ int32_t ViEReceiver::OnReceivedPayloadData(
   return 0;
 }
 
-void ViEReceiver::CalculateCaptureNtpTime(WebRtcRTPHeader* rtp_header) {
-  if (rtcp_list_.size() < 2) {
-    // We need two RTCP SR reports to calculate NTP.
-    return;
-  }
-
-  int64_t sender_capture_ntp_ms = 0;
-  if (!RtpToNtpMs(rtp_header->header.timestamp,
-                  rtcp_list_,
-                  &sender_capture_ntp_ms)) {
-    return;
-  }
-  uint32_t timestamp = sender_capture_ntp_ms * 90;
-  int64_t receiver_capture_ms =
-      ts_extrapolator_->ExtrapolateLocalTime(timestamp);
-  int64_t ntp_offset =
-      clock_->CurrentNtpInMilliseconds() - clock_->TimeInMilliseconds();
-  rtp_header->ntp_time_ms = receiver_capture_ms + ntp_offset;
-}
-
 bool ViEReceiver::OnRecoveredPacket(const uint8_t* rtp_packet,
                                     int rtp_packet_length) {
   RTPHeader header;
@@ -352,56 +333,13 @@ int ViEReceiver::InsertRTCPPacket(const uint8_t* rtcp_packet,
     return ret;
   }
 
-  if (!GetRtcpTimestamp()) {
+  if (!ntp_estimator_->UpdateRtcpTimestamp(rtp_receiver_->SSRC(), rtp_rtcp_)) {
     LOG(LS_WARNING) << "Failed to retrieve timestamp information from RTCP SR.";
   }
 
   return 0;
 }
 
-bool ViEReceiver::GetRtcpTimestamp() {
-  uint16_t rtt = 0;
-  rtp_rtcp_->RTT(rtp_receiver_->SSRC(), &rtt, NULL, NULL, NULL);
-  if (rtt == 0) {
-    // Waiting for valid rtt.
-    return true;
-  }
-
-  // Update RTCP list
-  uint32_t ntp_secs = 0;
-  uint32_t ntp_frac = 0;
-  uint32_t rtp_timestamp = 0;
-  if (0 != rtp_rtcp_->RemoteNTP(&ntp_secs,
-                                &ntp_frac,
-                                NULL,
-                                NULL,
-                                &rtp_timestamp)) {
-    return false;
-  }
-
-  bool new_rtcp_sr = false;
-  if (!UpdateRtcpList(ntp_secs,
-                      ntp_frac,
-                      rtp_timestamp,
-                      &rtcp_list_,
-                      &new_rtcp_sr)) {
-    return false;
-  }
-
-  if (!new_rtcp_sr) {
-    // No new RTCP SR since last time this function was called.
-    return true;
-  }
-
-  // Update extrapolator with the new arrival time.
-  // The extrapolator assumes the TimeInMilliseconds time.
-  int64_t receiver_arrival_time = clock_->TimeInMilliseconds();
-  int64_t sender_send_time_ms = Clock::NtpToMs(ntp_secs, ntp_frac);
-  int64_t sender_arrival_time_90k = (sender_send_time_ms + rtt / 2) * 90;
-  ts_extrapolator_->Update(receiver_arrival_time, sender_arrival_time_90k);
-  return true;
-}
-
 void ViEReceiver::StartReceive() {
   CriticalSectionScoped cs(receive_cs_.get());
   receiving_ = true;

webrtc/video_engine/vie_receiver.h

@@ -16,7 +16,6 @@
 #include "webrtc/engine_configurations.h"
 #include "webrtc/modules/rtp_rtcp/interface/receive_statistics.h"
 #include "webrtc/modules/rtp_rtcp/interface/rtp_rtcp_defines.h"
-#include "webrtc/system_wrappers/interface/rtp_to_ntp.h"
 #include "webrtc/system_wrappers/interface/scoped_ptr.h"
 #include "webrtc/typedefs.h"
 #include "webrtc/video_engine/include/vie_network.h"
@@ -26,6 +25,7 @@ namespace webrtc {
 
 class CriticalSectionWrapper;
 class FecReceiver;
+class RemoteNtpTimeEstimator;
 class ReceiveStatistics;
 class RemoteBitrateEstimator;
 class RtpDump;
@@ -33,7 +33,6 @@ class RtpHeaderParser;
 class RTPPayloadRegistry;
 class RtpReceiver;
 class RtpRtcp;
-class TimestampExtrapolator;
 class VideoCodingModule;
 struct ReceiveBandwidthEstimatorStats;
 
@@ -105,9 +104,6 @@ class ViEReceiver : public RtpData {
   bool IsPacketInOrder(const RTPHeader& header) const;
   bool IsPacketRetransmitted(const RTPHeader& header, bool in_order) const;
 
-  bool GetRtcpTimestamp();
-  void CalculateCaptureNtpTime(WebRtcRTPHeader* rtp_header);
-
   scoped_ptr<CriticalSectionWrapper> receive_cs_;
   scoped_ptr<RtpHeaderParser> rtp_header_parser_;
   scoped_ptr<RTPPayloadRegistry> rtp_payload_registry_;
@@ -119,9 +115,7 @@ class ViEReceiver : public RtpData {
   VideoCodingModule* vcm_;
   RemoteBitrateEstimator* remote_bitrate_estimator_;
 
-  Clock* clock_;
-  scoped_ptr<TimestampExtrapolator> ts_extrapolator_;
-  RtcpList rtcp_list_;
+  scoped_ptr<RemoteNtpTimeEstimator> ntp_estimator_;
 
   RtpDump* rtp_dump_;
   bool receiving_;