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/*
* 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.
*/
#include <algorithm>
#include <math.h>
#include "testing/gtest/include/gtest/gtest.h"
#include "webrtc/video_engine/stream_synchronization.h"
namespace webrtc {
// These correspond to the same constants defined in vie_sync_module.cc.
enum { kMaxVideoDiffMs = 80 };
enum { kMaxAudioDiffMs = 80 };
enum { kMaxDelay = 1500 };
// Test constants.
enum { kDefaultAudioFrequency = 8000 };
enum { kDefaultVideoFrequency = 90000 };
const double kNtpFracPerMs = 4.294967296E6;
static const int kSmoothingFilter = 4 * 2;
class Time {
public:
explicit Time(int64_t offset)
: kNtpJan1970(2208988800UL),
time_now_ms_(offset) {}
RtcpMeasurement GenerateRtcp(int frequency, uint32_t offset) const {
RtcpMeasurement rtcp;
NowNtp(&rtcp.ntp_secs, &rtcp.ntp_frac);
rtcp.rtp_timestamp = NowRtp(frequency, offset);
return rtcp;
}
void NowNtp(uint32_t* ntp_secs, uint32_t* ntp_frac) const {
*ntp_secs = time_now_ms_ / 1000 + kNtpJan1970;
int64_t remainder_ms = time_now_ms_ % 1000;
*ntp_frac = static_cast<uint32_t>(
static_cast<double>(remainder_ms) * kNtpFracPerMs + 0.5);
}
uint32_t NowRtp(int frequency, uint32_t offset) const {
return frequency * time_now_ms_ / 1000 + offset;
}
void IncreaseTimeMs(int64_t inc) {
time_now_ms_ += inc;
}
int64_t time_now_ms() const {
return time_now_ms_;
}
private:
// January 1970, in NTP seconds.
const uint32_t kNtpJan1970;
int64_t time_now_ms_;
};
class StreamSynchronizationTest : public ::testing::Test {
protected:
virtual void SetUp() {
sync_ = new StreamSynchronization(0, 0);
send_time_ = new Time(kSendTimeOffsetMs);
receive_time_ = new Time(kReceiveTimeOffsetMs);
audio_clock_drift_ = 1.0;
video_clock_drift_ = 1.0;
}
virtual void TearDown() {
delete sync_;
delete send_time_;
delete receive_time_;
}
// Generates the necessary RTCP measurements and RTP timestamps and computes
// the audio and video delays needed to get the two streams in sync.
// |audio_delay_ms| and |video_delay_ms| are the number of milliseconds after
// capture which the frames are rendered.
// |current_audio_delay_ms| is the number of milliseconds which audio is
// currently being delayed by the receiver.
bool DelayedStreams(int audio_delay_ms,
int video_delay_ms,
int current_audio_delay_ms,
int* extra_audio_delay_ms,
int* total_video_delay_ms) {
int audio_frequency = static_cast<int>(kDefaultAudioFrequency *
audio_clock_drift_ + 0.5);
int audio_offset = 0;
int video_frequency = static_cast<int>(kDefaultVideoFrequency *
video_clock_drift_ + 0.5);
int video_offset = 0;
StreamSynchronization::Measurements audio;
StreamSynchronization::Measurements video;
// Generate NTP/RTP timestamp pair for both streams corresponding to RTCP.
audio.rtcp.push_front(send_time_->GenerateRtcp(audio_frequency,
audio_offset));
send_time_->IncreaseTimeMs(100);
receive_time_->IncreaseTimeMs(100);
video.rtcp.push_front(send_time_->GenerateRtcp(video_frequency,
video_offset));
send_time_->IncreaseTimeMs(900);
receive_time_->IncreaseTimeMs(900);
audio.rtcp.push_front(send_time_->GenerateRtcp(audio_frequency,
audio_offset));
send_time_->IncreaseTimeMs(100);
receive_time_->IncreaseTimeMs(100);
video.rtcp.push_front(send_time_->GenerateRtcp(video_frequency,
video_offset));
send_time_->IncreaseTimeMs(900);
receive_time_->IncreaseTimeMs(900);
// Capture an audio and a video frame at the same time.
audio.latest_timestamp = send_time_->NowRtp(audio_frequency,
audio_offset);
video.latest_timestamp = send_time_->NowRtp(video_frequency,
video_offset);
if (audio_delay_ms > video_delay_ms) {
// Audio later than video.
receive_time_->IncreaseTimeMs(video_delay_ms);
video.latest_receive_time_ms = receive_time_->time_now_ms();
receive_time_->IncreaseTimeMs(audio_delay_ms - video_delay_ms);
audio.latest_receive_time_ms = receive_time_->time_now_ms();
} else {
// Video later than audio.
receive_time_->IncreaseTimeMs(audio_delay_ms);
audio.latest_receive_time_ms = receive_time_->time_now_ms();
receive_time_->IncreaseTimeMs(video_delay_ms - audio_delay_ms);
video.latest_receive_time_ms = receive_time_->time_now_ms();
}
int relative_delay_ms;
StreamSynchronization::ComputeRelativeDelay(audio, video,
&relative_delay_ms);
EXPECT_EQ(video_delay_ms - audio_delay_ms, relative_delay_ms);
return sync_->ComputeDelays(relative_delay_ms,
current_audio_delay_ms,
extra_audio_delay_ms,
total_video_delay_ms);
}
// Simulate audio playback 300 ms after capture and video rendering 100 ms
// after capture. Verify that the correct extra delays are calculated for
// audio and video, and that they change correctly when we simulate that
// NetEQ or the VCM adds more delay to the streams.
// TODO(holmer): This is currently wrong! We should simply change
// audio_delay_ms or video_delay_ms since those now include VCM and NetEQ
// delays.
void BothDelayedAudioLaterTest(int base_target_delay) {
int current_audio_delay_ms = base_target_delay;
int audio_delay_ms = base_target_delay + 300;
int video_delay_ms = base_target_delay + 100;
int extra_audio_delay_ms = 0;
int total_video_delay_ms = base_target_delay;
int filtered_move = (audio_delay_ms - video_delay_ms) / kSmoothingFilter;
const int kNeteqDelayIncrease = 50;
const int kNeteqDelayDecrease = 10;
EXPECT_TRUE(DelayedStreams(audio_delay_ms,
video_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms,
&total_video_delay_ms));
EXPECT_EQ(base_target_delay + filtered_move, total_video_delay_ms);
EXPECT_EQ(base_target_delay, extra_audio_delay_ms);
current_audio_delay_ms = extra_audio_delay_ms;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(1000 - std::max(audio_delay_ms,
video_delay_ms));
// Simulate base_target_delay minimum delay in the VCM.
total_video_delay_ms = base_target_delay;
EXPECT_TRUE(DelayedStreams(audio_delay_ms,
video_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms,
&total_video_delay_ms));
EXPECT_EQ(base_target_delay + 2 * filtered_move, total_video_delay_ms);
EXPECT_EQ(base_target_delay, extra_audio_delay_ms);
current_audio_delay_ms = extra_audio_delay_ms;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(1000 - std::max(audio_delay_ms,
video_delay_ms));
// Simulate base_target_delay minimum delay in the VCM.
total_video_delay_ms = base_target_delay;
EXPECT_TRUE(DelayedStreams(audio_delay_ms,
video_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms,
&total_video_delay_ms));
EXPECT_EQ(base_target_delay + 3 * filtered_move, total_video_delay_ms);
EXPECT_EQ(base_target_delay, extra_audio_delay_ms);
// Simulate that NetEQ introduces some audio delay.
current_audio_delay_ms = base_target_delay + kNeteqDelayIncrease;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(1000 - std::max(audio_delay_ms,
video_delay_ms));
// Simulate base_target_delay minimum delay in the VCM.
total_video_delay_ms = base_target_delay;
EXPECT_TRUE(DelayedStreams(audio_delay_ms,
video_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms,
&total_video_delay_ms));
filtered_move = 3 * filtered_move +
(kNeteqDelayIncrease + audio_delay_ms - video_delay_ms) /
kSmoothingFilter;
EXPECT_EQ(base_target_delay + filtered_move, total_video_delay_ms);
EXPECT_EQ(base_target_delay, extra_audio_delay_ms);
// Simulate that NetEQ reduces its delay.
current_audio_delay_ms = base_target_delay + kNeteqDelayDecrease;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(1000 - std::max(audio_delay_ms,
video_delay_ms));
// Simulate base_target_delay minimum delay in the VCM.
total_video_delay_ms = base_target_delay;
EXPECT_TRUE(DelayedStreams(audio_delay_ms,
video_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms,
&total_video_delay_ms));
filtered_move = filtered_move +
(kNeteqDelayDecrease + audio_delay_ms - video_delay_ms) /
kSmoothingFilter;
EXPECT_EQ(base_target_delay + filtered_move, total_video_delay_ms);
EXPECT_EQ(base_target_delay, extra_audio_delay_ms);
}
void BothDelayedVideoLaterTest(int base_target_delay) {
int current_audio_delay_ms = base_target_delay;
int audio_delay_ms = base_target_delay + 100;
int video_delay_ms = base_target_delay + 300;
int extra_audio_delay_ms = 0;
int total_video_delay_ms = base_target_delay;
EXPECT_TRUE(DelayedStreams(audio_delay_ms,
video_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms,
&total_video_delay_ms));
EXPECT_EQ(base_target_delay, total_video_delay_ms);
// The audio delay is not allowed to change more than this in 1 second.
EXPECT_GE(base_target_delay + kMaxAudioDiffMs, extra_audio_delay_ms);
current_audio_delay_ms = extra_audio_delay_ms;
int current_extra_delay_ms = extra_audio_delay_ms;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(800);
EXPECT_TRUE(DelayedStreams(audio_delay_ms,
video_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms,
&total_video_delay_ms));
EXPECT_EQ(base_target_delay, total_video_delay_ms);
// The audio delay is not allowed to change more than the half of the
// required change in delay.
EXPECT_EQ(current_extra_delay_ms + MaxAudioDelayIncrease(
current_audio_delay_ms,
base_target_delay + video_delay_ms - audio_delay_ms),
extra_audio_delay_ms);
current_audio_delay_ms = extra_audio_delay_ms;
current_extra_delay_ms = extra_audio_delay_ms;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(800);
EXPECT_TRUE(DelayedStreams(audio_delay_ms,
video_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms,
&total_video_delay_ms));
EXPECT_EQ(base_target_delay, total_video_delay_ms);
// The audio delay is not allowed to change more than the half of the
// required change in delay.
EXPECT_EQ(current_extra_delay_ms + MaxAudioDelayIncrease(
current_audio_delay_ms,
base_target_delay + video_delay_ms - audio_delay_ms),
extra_audio_delay_ms);
current_extra_delay_ms = extra_audio_delay_ms;
// Simulate that NetEQ for some reason reduced the delay.
current_audio_delay_ms = base_target_delay + 10;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(800);
EXPECT_TRUE(DelayedStreams(audio_delay_ms,
video_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms,
&total_video_delay_ms));
EXPECT_EQ(base_target_delay, total_video_delay_ms);
// Since we only can ask NetEQ for a certain amount of extra delay, and
// we only measure the total NetEQ delay, we will ask for additional delay
// here to try to stay in sync.
EXPECT_EQ(current_extra_delay_ms + MaxAudioDelayIncrease(
current_audio_delay_ms,
base_target_delay + video_delay_ms - audio_delay_ms),
extra_audio_delay_ms);
current_extra_delay_ms = extra_audio_delay_ms;
// Simulate that NetEQ for some reason significantly increased the delay.
current_audio_delay_ms = base_target_delay + 350;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(800);
EXPECT_TRUE(DelayedStreams(audio_delay_ms,
video_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms,
&total_video_delay_ms));
EXPECT_EQ(base_target_delay, total_video_delay_ms);
// The audio delay is not allowed to change more than the half of the
// required change in delay.
EXPECT_EQ(current_extra_delay_ms + MaxAudioDelayIncrease(
current_audio_delay_ms,
base_target_delay + video_delay_ms - audio_delay_ms),
extra_audio_delay_ms);
}
int MaxAudioDelayIncrease(int current_audio_delay_ms, int delay_ms) {
return std::min((delay_ms - current_audio_delay_ms) / kSmoothingFilter,
static_cast<int>(kMaxAudioDiffMs));
}
int MaxAudioDelayDecrease(int current_audio_delay_ms, int delay_ms) {
return std::max((delay_ms - current_audio_delay_ms) / kSmoothingFilter,
-kMaxAudioDiffMs);
}
enum { kSendTimeOffsetMs = 98765 };
enum { kReceiveTimeOffsetMs = 43210 };
StreamSynchronization* sync_;
Time* send_time_; // The simulated clock at the sender.
Time* receive_time_; // The simulated clock at the receiver.
double audio_clock_drift_;
double video_clock_drift_;
};
TEST_F(StreamSynchronizationTest, NoDelay) {
uint32_t current_audio_delay_ms = 0;
int extra_audio_delay_ms = 0;
int total_video_delay_ms = 0;
EXPECT_FALSE(DelayedStreams(0, 0, current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
EXPECT_EQ(0, extra_audio_delay_ms);
EXPECT_EQ(0, total_video_delay_ms);
}
TEST_F(StreamSynchronizationTest, VideoDelay) {
uint32_t current_audio_delay_ms = 0;
int delay_ms = 200;
int extra_audio_delay_ms = 0;
int total_video_delay_ms = 0;
EXPECT_TRUE(DelayedStreams(delay_ms, 0, current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
EXPECT_EQ(0, extra_audio_delay_ms);
// The video delay is not allowed to change more than this in 1 second.
EXPECT_EQ(delay_ms / kSmoothingFilter, total_video_delay_ms);
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(800);
// Simulate 0 minimum delay in the VCM.
total_video_delay_ms = 0;
EXPECT_TRUE(DelayedStreams(delay_ms, 0, current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
EXPECT_EQ(0, extra_audio_delay_ms);
// The video delay is not allowed to change more than this in 1 second.
EXPECT_EQ(2 * delay_ms / kSmoothingFilter, total_video_delay_ms);
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(800);
// Simulate 0 minimum delay in the VCM.
total_video_delay_ms = 0;
EXPECT_TRUE(DelayedStreams(delay_ms, 0, current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
EXPECT_EQ(0, extra_audio_delay_ms);
EXPECT_EQ(3 * delay_ms / kSmoothingFilter, total_video_delay_ms);
}
TEST_F(StreamSynchronizationTest, AudioDelay) {
int current_audio_delay_ms = 0;
int delay_ms = 200;
int extra_audio_delay_ms = 0;
int total_video_delay_ms = 0;
EXPECT_TRUE(DelayedStreams(0, delay_ms, current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
EXPECT_EQ(0, total_video_delay_ms);
// The audio delay is not allowed to change more than this in 1 second.
EXPECT_EQ(delay_ms / kSmoothingFilter, extra_audio_delay_ms);
current_audio_delay_ms = extra_audio_delay_ms;
int current_extra_delay_ms = extra_audio_delay_ms;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(800);
EXPECT_TRUE(DelayedStreams(0, delay_ms, current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
EXPECT_EQ(0, total_video_delay_ms);
// The audio delay is not allowed to change more than the half of the required
// change in delay.
EXPECT_EQ(current_extra_delay_ms +
MaxAudioDelayIncrease(current_audio_delay_ms, delay_ms),
extra_audio_delay_ms);
current_audio_delay_ms = extra_audio_delay_ms;
current_extra_delay_ms = extra_audio_delay_ms;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(800);
EXPECT_TRUE(DelayedStreams(0, delay_ms, current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
EXPECT_EQ(0, total_video_delay_ms);
// The audio delay is not allowed to change more than the half of the required
// change in delay.
EXPECT_EQ(current_extra_delay_ms +
MaxAudioDelayIncrease(current_audio_delay_ms, delay_ms),
extra_audio_delay_ms);
current_extra_delay_ms = extra_audio_delay_ms;
// Simulate that NetEQ for some reason reduced the delay.
current_audio_delay_ms = 10;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(800);
EXPECT_TRUE(DelayedStreams(0, delay_ms, current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
EXPECT_EQ(0, total_video_delay_ms);
// Since we only can ask NetEQ for a certain amount of extra delay, and
// we only measure the total NetEQ delay, we will ask for additional delay
// here to try to
EXPECT_EQ(current_extra_delay_ms +
MaxAudioDelayIncrease(current_audio_delay_ms, delay_ms),
extra_audio_delay_ms);
current_extra_delay_ms = extra_audio_delay_ms;
// Simulate that NetEQ for some reason significantly increased the delay.
current_audio_delay_ms = 350;
send_time_->IncreaseTimeMs(1000);
receive_time_->IncreaseTimeMs(800);
EXPECT_TRUE(DelayedStreams(0, delay_ms, current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
EXPECT_EQ(0, total_video_delay_ms);
// The audio delay is not allowed to change more than the half of the required
// change in delay.
EXPECT_EQ(current_extra_delay_ms +
MaxAudioDelayDecrease(current_audio_delay_ms, delay_ms),
extra_audio_delay_ms);
}
TEST_F(StreamSynchronizationTest, BothDelayedVideoLater) {
BothDelayedVideoLaterTest(0);
}
TEST_F(StreamSynchronizationTest, BothDelayedVideoLaterAudioClockDrift) {
audio_clock_drift_ = 1.05;
BothDelayedVideoLaterTest(0);
}
TEST_F(StreamSynchronizationTest, BothDelayedVideoLaterVideoClockDrift) {
video_clock_drift_ = 1.05;
BothDelayedVideoLaterTest(0);
}
TEST_F(StreamSynchronizationTest, BothDelayedAudioLater) {
BothDelayedAudioLaterTest(0);
}
TEST_F(StreamSynchronizationTest, BothDelayedAudioClockDrift) {
audio_clock_drift_ = 1.05;
BothDelayedAudioLaterTest(0);
}
TEST_F(StreamSynchronizationTest, BothDelayedVideoClockDrift) {
video_clock_drift_ = 1.05;
BothDelayedAudioLaterTest(0);
}
TEST_F(StreamSynchronizationTest, BaseDelay) {
int base_target_delay_ms = 2000;
int current_audio_delay_ms = 2000;
int extra_audio_delay_ms = 0;
int total_video_delay_ms = base_target_delay_ms;
sync_->SetTargetBufferingDelay(base_target_delay_ms);
// We are in sync don't change.
EXPECT_FALSE(DelayedStreams(base_target_delay_ms, base_target_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
// Triggering another call with the same values. Delay should not be modified.
base_target_delay_ms = 2000;
current_audio_delay_ms = base_target_delay_ms;
total_video_delay_ms = base_target_delay_ms;
sync_->SetTargetBufferingDelay(base_target_delay_ms);
// We are in sync don't change.
EXPECT_FALSE(DelayedStreams(base_target_delay_ms, base_target_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
// Changing delay value - intended to test this module only. In practice it
// would take VoE time to adapt.
base_target_delay_ms = 5000;
current_audio_delay_ms = base_target_delay_ms;
total_video_delay_ms = base_target_delay_ms;
sync_->SetTargetBufferingDelay(base_target_delay_ms);
// We are in sync don't change.
EXPECT_FALSE(DelayedStreams(base_target_delay_ms, base_target_delay_ms,
current_audio_delay_ms,
&extra_audio_delay_ms, &total_video_delay_ms));
}
TEST_F(StreamSynchronizationTest, BothDelayedAudioLaterWithBaseDelay) {
int base_target_delay_ms = 3000;
sync_->SetTargetBufferingDelay(base_target_delay_ms);
BothDelayedAudioLaterTest(base_target_delay_ms);
}
TEST_F(StreamSynchronizationTest, BothDelayedAudioClockDriftWithBaseDelay) {
int base_target_delay_ms = 3000;
sync_->SetTargetBufferingDelay(base_target_delay_ms);
audio_clock_drift_ = 1.05;
BothDelayedAudioLaterTest(base_target_delay_ms);
}
TEST_F(StreamSynchronizationTest, BothDelayedVideoClockDriftWithBaseDelay) {
int base_target_delay_ms = 3000;
sync_->SetTargetBufferingDelay(base_target_delay_ms);
video_clock_drift_ = 1.05;
BothDelayedAudioLaterTest(base_target_delay_ms);
}
TEST_F(StreamSynchronizationTest, BothDelayedVideoLaterWithBaseDelay) {
int base_target_delay_ms = 2000;
sync_->SetTargetBufferingDelay(base_target_delay_ms);
BothDelayedVideoLaterTest(base_target_delay_ms);
}
TEST_F(StreamSynchronizationTest,
BothDelayedVideoLaterAudioClockDriftWithBaseDelay) {
int base_target_delay_ms = 2000;
audio_clock_drift_ = 1.05;
sync_->SetTargetBufferingDelay(base_target_delay_ms);
BothDelayedVideoLaterTest(base_target_delay_ms);
}
TEST_F(StreamSynchronizationTest,
BothDelayedVideoLaterVideoClockDriftWithBaseDelay) {
int base_target_delay_ms = 2000;
video_clock_drift_ = 1.05;
sync_->SetTargetBufferingDelay(base_target_delay_ms);
BothDelayedVideoLaterTest(base_target_delay_ms);
}
} // namespace webrtc