Don't use wall clock for stats
This uses the local NTP clock for RTCP report block stats.
This code exists in the version that Mozilla is shipping, with a review
here https://phabricator.services.mozilla.com/D127709 .
Bug: webrtc:13484
Change-Id: I2f46ec02acab0bbb09040778b05b248c2d815bd1
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/240142
Reviewed-by: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35787}
diff --git a/audio/channel_receive.cc b/audio/channel_receive.cc
index 97708dc..f2fd34a 100644
--- a/audio/channel_receive.cc
+++ b/audio/channel_receive.cc
@@ -846,14 +846,11 @@
absl::optional<RtpRtcpInterface::SenderReportStats> rtcp_sr_stats =
rtp_rtcp_->GetSenderReportStats();
if (rtcp_sr_stats.has_value()) {
- // Number of seconds since 1900 January 1 00:00 GMT (see
- // https://tools.ietf.org/html/rfc868).
- constexpr int64_t kNtpJan1970Millisecs =
- 2208988800 * rtc::kNumMillisecsPerSec;
stats.last_sender_report_timestamp_ms =
- rtcp_sr_stats->last_arrival_timestamp.ToMs() - kNtpJan1970Millisecs;
+ rtcp_sr_stats->last_arrival_timestamp.ToMs() -
+ rtc::kNtpJan1970Millisecs;
stats.last_sender_report_remote_timestamp_ms =
- rtcp_sr_stats->last_remote_timestamp.ToMs() - kNtpJan1970Millisecs;
+ rtcp_sr_stats->last_remote_timestamp.ToMs() - rtc::kNtpJan1970Millisecs;
stats.sender_reports_packets_sent = rtcp_sr_stats->packets_sent;
stats.sender_reports_bytes_sent = rtcp_sr_stats->bytes_sent;
stats.sender_reports_reports_count = rtcp_sr_stats->reports_count;
diff --git a/modules/rtp_rtcp/source/receive_statistics_impl.cc b/modules/rtp_rtcp/source/receive_statistics_impl.cc
index b16f122..d2dba66 100644
--- a/modules/rtp_rtcp/source/receive_statistics_impl.cc
+++ b/modules/rtp_rtcp/source/receive_statistics_impl.cc
@@ -22,16 +22,13 @@
#include "modules/rtp_rtcp/source/rtp_rtcp_config.h"
#include "modules/rtp_rtcp/source/time_util.h"
#include "rtc_base/logging.h"
+#include "rtc_base/time_utils.h"
#include "system_wrappers/include/clock.h"
namespace webrtc {
namespace {
constexpr int64_t kStatisticsTimeoutMs = 8000;
constexpr int64_t kStatisticsProcessIntervalMs = 1000;
-
-// Number of seconds since 1900 January 1 00:00 GMT (see
-// https://tools.ietf.org/html/rfc868).
-constexpr int64_t kNtpJan1970Millisecs = 2'208'988'800'000;
} // namespace
StreamStatistician::~StreamStatistician() {}
@@ -43,7 +40,7 @@
clock_(clock),
delta_internal_unix_epoch_ms_(clock_->CurrentNtpInMilliseconds() -
clock_->TimeInMilliseconds() -
- kNtpJan1970Millisecs),
+ rtc::kNtpJan1970Millisecs),
incoming_bitrate_(kStatisticsProcessIntervalMs,
RateStatistics::kBpsScale),
max_reordering_threshold_(max_reordering_threshold),
diff --git a/modules/rtp_rtcp/source/rtcp_receiver.cc b/modules/rtp_rtcp/source/rtcp_receiver.cc
index 47843be..d0f9596 100644
--- a/modules/rtp_rtcp/source/rtcp_receiver.cc
+++ b/modules/rtp_rtcp/source/rtcp_receiver.cc
@@ -662,7 +662,12 @@
rtcp_report_block.delay_since_last_sender_report =
report_block.delay_since_last_sr();
rtcp_report_block.last_sender_report_timestamp = report_block.last_sr();
- report_block_data->SetReportBlock(rtcp_report_block, rtc::TimeUTCMicros());
+ // Number of seconds since 1900 January 1 00:00 GMT (see
+ // https://tools.ietf.org/html/rfc868).
+ report_block_data->SetReportBlock(
+ rtcp_report_block,
+ (clock_->CurrentNtpInMilliseconds() - rtc::kNtpJan1970Millisecs) *
+ rtc::kNumMicrosecsPerMillisec);
int64_t rtt_ms = 0;
uint32_t send_time_ntp = report_block.last_sr();
diff --git a/modules/rtp_rtcp/source/rtcp_receiver_unittest.cc b/modules/rtp_rtcp/source/rtcp_receiver_unittest.cc
index fa7d569..eb5d265 100644
--- a/modules/rtp_rtcp/source/rtcp_receiver_unittest.cc
+++ b/modules/rtp_rtcp/source/rtcp_receiver_unittest.cc
@@ -1573,12 +1573,8 @@
const uint32_t kCumulativeLoss = 7;
const uint32_t kJitter = 9;
const uint16_t kSequenceNumber = 1234;
- const int64_t kUtcNowUs = 42;
-
- // The "report_block_timestamp_utc_us" is obtained from the global UTC clock
- // (not the simulcated `mocks.clock`) and requires a scoped fake clock.
- rtc::ScopedFakeClock fake_clock;
- fake_clock.SetTime(Timestamp::Micros(kUtcNowUs));
+ const int64_t kNtpNowMs =
+ mocks.clock.CurrentNtpInMilliseconds() - rtc::kNtpJan1970Millisecs;
rtcp::ReportBlock rtcp_block;
rtcp_block.SetMediaSsrc(kReceiverMainSsrc);
@@ -1601,7 +1597,8 @@
EXPECT_EQ(rtcp_block.extended_high_seq_num(),
report_block.extended_highest_sequence_number);
EXPECT_EQ(rtcp_block.jitter(), report_block.jitter);
- EXPECT_EQ(kUtcNowUs, report_block_data.report_block_timestamp_utc_us());
+ EXPECT_EQ(kNtpNowMs * rtc::kNumMicrosecsPerMillisec,
+ report_block_data.report_block_timestamp_utc_us());
// No RTT is calculated in this test.
EXPECT_EQ(0u, report_block_data.num_rtts());
});
diff --git a/rtc_base/time_utils.h b/rtc_base/time_utils.h
index de3c58c..6a3cfda 100644
--- a/rtc_base/time_utils.h
+++ b/rtc_base/time_utils.h
@@ -31,6 +31,12 @@
static const int64_t kNumNanosecsPerMicrosec =
kNumNanosecsPerSec / kNumMicrosecsPerSec;
+// Elapsed milliseconds between NTP base, 1900 January 1 00:00 GMT
+// (see https://tools.ietf.org/html/rfc868), and January 1 00:00 GMT 1970
+// epoch. This is useful when converting between the NTP time base and the
+// time base used in RTCP reports.
+constexpr int64_t kNtpJan1970Millisecs = 2'208'988'800 * kNumMillisecsPerSec;
+
// TODO(honghaiz): Define a type for the time value specifically.
class ClockInterface {
