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1 /*
2  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_REMOTE_BITRATE_ESTIMATOR_UNITTEST_HELPER_H_
12 #define WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_REMOTE_BITRATE_ESTIMATOR_UNITTEST_HELPER_H_
13 
14 #include <list>
15 #include <map>
16 #include <utility>
17 #include <vector>
18 
19 #include "testing/gtest/include/gtest/gtest.h"
20 #include "webrtc/base/constructormagic.h"
21 #include "webrtc/base/scoped_ptr.h"
22 #include "webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h"
23 #include "webrtc/system_wrappers/include/clock.h"
24 
25 namespace webrtc {
26 namespace testing {
27 
28 class TestBitrateObserver : public RemoteBitrateObserver {
29  public:
TestBitrateObserver()30   TestBitrateObserver() : updated_(false), latest_bitrate_(0) {}
~TestBitrateObserver()31   virtual ~TestBitrateObserver() {}
32 
33   void OnReceiveBitrateChanged(const std::vector<unsigned int>& ssrcs,
34                                unsigned int bitrate) override;
35 
Reset()36   void Reset() { updated_ = false; }
37 
updated()38   bool updated() const { return updated_; }
39 
latest_bitrate()40   unsigned int latest_bitrate() const { return latest_bitrate_; }
41 
42  private:
43   bool updated_;
44   unsigned int latest_bitrate_;
45 };
46 
47 class RtpStream {
48  public:
49   struct RtpPacket {
50     int64_t send_time;
51     int64_t arrival_time;
52     uint32_t rtp_timestamp;
53     size_t size;
54     unsigned int ssrc;
55   };
56 
57   struct RtcpPacket {
58     uint32_t ntp_secs;
59     uint32_t ntp_frac;
60     uint32_t timestamp;
61     unsigned int ssrc;
62   };
63 
64   typedef std::list<RtpPacket*> PacketList;
65 
66   enum { kSendSideOffsetUs = 1000000 };
67 
68   RtpStream(int fps, int bitrate_bps, unsigned int ssrc, unsigned int frequency,
69       uint32_t timestamp_offset, int64_t rtcp_receive_time);
70   void set_rtp_timestamp_offset(uint32_t offset);
71 
72   // Generates a new frame for this stream. If called too soon after the
73   // previous frame, no frame will be generated. The frame is split into
74   // packets.
75   int64_t GenerateFrame(int64_t time_now_us, PacketList* packets);
76 
77   // The send-side time when the next frame can be generated.
78   double next_rtp_time() const;
79 
80   // Generates an RTCP packet.
81   RtcpPacket* Rtcp(int64_t time_now_us);
82 
83   void set_bitrate_bps(int bitrate_bps);
84 
85   int bitrate_bps() const;
86 
87   unsigned int ssrc() const;
88 
89   static bool Compare(const std::pair<unsigned int, RtpStream*>& left,
90                       const std::pair<unsigned int, RtpStream*>& right);
91 
92  private:
93   enum { kRtcpIntervalUs = 1000000 };
94 
95   int fps_;
96   int bitrate_bps_;
97   unsigned int ssrc_;
98   unsigned int frequency_;
99   int64_t next_rtp_time_;
100   int64_t next_rtcp_time_;
101   uint32_t rtp_timestamp_offset_;
102   const double kNtpFracPerMs;
103 
104   RTC_DISALLOW_COPY_AND_ASSIGN(RtpStream);
105 };
106 
107 class StreamGenerator {
108  public:
109   typedef std::list<RtpStream::RtcpPacket*> RtcpList;
110 
111   StreamGenerator(int capacity, double time_now);
112 
113   ~StreamGenerator();
114 
115   // Add a new stream.
116   void AddStream(RtpStream* stream);
117 
118   // Set the link capacity.
119   void set_capacity_bps(int capacity_bps);
120 
121   // Divides |bitrate_bps| among all streams. The allocated bitrate per stream
122   // is decided by the initial allocation ratios.
123   void SetBitrateBps(int bitrate_bps);
124 
125   // Set the RTP timestamp offset for the stream identified by |ssrc|.
126   void set_rtp_timestamp_offset(unsigned int ssrc, uint32_t offset);
127 
128   // TODO(holmer): Break out the channel simulation part from this class to make
129   // it possible to simulate different types of channels.
130   int64_t GenerateFrame(RtpStream::PacketList* packets, int64_t time_now_us);
131 
132  private:
133   typedef std::map<unsigned int, RtpStream*> StreamMap;
134 
135   // Capacity of the simulated channel in bits per second.
136   int capacity_;
137   // The time when the last packet arrived.
138   int64_t prev_arrival_time_us_;
139   // All streams being transmitted on this simulated channel.
140   StreamMap streams_;
141 
142   RTC_DISALLOW_COPY_AND_ASSIGN(StreamGenerator);
143 };
144 }  // namespace testing
145 
146 class RemoteBitrateEstimatorTest : public ::testing::Test {
147  public:
148   RemoteBitrateEstimatorTest();
149   virtual ~RemoteBitrateEstimatorTest();
150 
151  protected:
152   virtual void SetUp() = 0;
153 
154   void AddDefaultStream();
155 
156   // Helper to convert some time format to resolution used in absolute send time
157   // header extension, rounded upwards. |t| is the time to convert, in some
158   // resolution. |denom| is the value to divide |t| by to get whole seconds,
159   // e.g. |denom| = 1000 if |t| is in milliseconds.
160   static uint32_t AbsSendTime(int64_t t, int64_t denom);
161 
162   // Helper to add two absolute send time values and keep it less than 1<<24.
163   static uint32_t AddAbsSendTime(uint32_t t1, uint32_t t2);
164 
165   // Helper to create a WebRtcRTPHeader containing the relevant data for the
166   // estimator (all other fields are cleared) and call IncomingPacket on the
167   // estimator.
168   void IncomingPacket(uint32_t ssrc,
169                       size_t payload_size,
170                       int64_t arrival_time,
171                       uint32_t rtp_timestamp,
172                       uint32_t absolute_send_time,
173                       bool was_paced);
174 
175   // Generates a frame of packets belonging to a stream at a given bitrate and
176   // with a given ssrc. The stream is pushed through a very simple simulated
177   // network, and is then given to the receive-side bandwidth estimator.
178   // Returns true if an over-use was seen, false otherwise.
179   // The StreamGenerator::updated() should be used to check for any changes in
180   // target bitrate after the call to this function.
181   bool GenerateAndProcessFrame(unsigned int ssrc, unsigned int bitrate_bps);
182 
183   // Run the bandwidth estimator with a stream of |number_of_frames| frames, or
184   // until it reaches |target_bitrate|.
185   // Can for instance be used to run the estimator for some time to get it
186   // into a steady state.
187   unsigned int SteadyStateRun(unsigned int ssrc,
188                               int number_of_frames,
189                               unsigned int start_bitrate,
190                               unsigned int min_bitrate,
191                               unsigned int max_bitrate,
192                               unsigned int target_bitrate);
193 
194   void TestTimestampGroupingTestHelper();
195 
196   void TestGetStatsHelper();
197 
198   void TestWrappingHelper(int silence_time_s);
199 
200   void InitialBehaviorTestHelper(unsigned int expected_converge_bitrate);
201   void RateIncreaseReorderingTestHelper(unsigned int expected_bitrate);
202   void RateIncreaseRtpTimestampsTestHelper(int expected_iterations);
203   void CapacityDropTestHelper(int number_of_streams,
204                               bool wrap_time_stamp,
205                               unsigned int expected_bitrate_drop_delta);
206 
207   static const unsigned int kDefaultSsrc;
208   static const int kArrivalTimeClockOffsetMs = 60000;
209 
210   SimulatedClock clock_;  // Time at the receiver.
211   rtc::scoped_ptr<testing::TestBitrateObserver> bitrate_observer_;
212   rtc::scoped_ptr<RemoteBitrateEstimator> bitrate_estimator_;
213   rtc::scoped_ptr<testing::StreamGenerator> stream_generator_;
214 
215   RTC_DISALLOW_COPY_AND_ASSIGN(RemoteBitrateEstimatorTest);
216 };
217 }  // namespace webrtc
218 
219 #endif  // WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_REMOTE_BITRATE_ESTIMATOR_UNITTEST_HELPER_H_
220