Reset frame timestamp epoch for new capturers.

talk/media/webrtc/webrtcvideoengine2_unittest.cc

Index: talk/media/webrtc/webrtcvideoengine2_unittest.cc
diff --git a/talk/media/webrtc/webrtcvideoengine2_unittest.cc b/talk/media/webrtc/webrtcvideoengine2_unittest.cc
index 71581de2e3e85f80d19c1c0e6eadab6c3a8f37ae..52acec40826a50e19fe3ed535f9ff530a4cd678f 100644
--- a/talk/media/webrtc/webrtcvideoengine2_unittest.cc
+++ b/talk/media/webrtc/webrtcvideoengine2_unittest.cc
@@ -440,18 +440,14 @@ TEST_F(WebRtcVideoEngine2Test, PropagatesInputFrameTimestamp) {
                                       cricket::FOURCC_I420));
   channel->SetSend(true);
 
-  FakeCall* call = factory.GetCall();
-  std::vector<FakeVideoSendStream*> streams = call->GetVideoSendStreams();
-  FakeVideoSendStream* stream = streams[0];
+  FakeVideoSendStream* stream = factory.GetCall()->GetVideoSendStreams()[0];
 
-  int64_t timestamp;
-  int64_t last_timestamp;
 
   EXPECT_TRUE(capturer.CaptureFrame());
-  last_timestamp = stream->GetLastTimestamp();
+  int64_t last_timestamp = stream->GetLastTimestamp();
   for (int i = 0; i < 10; i++) {
     EXPECT_TRUE(capturer.CaptureFrame());
-    timestamp = stream->GetLastTimestamp();
+    int64_t timestamp = stream->GetLastTimestamp();
     int64_t interval = timestamp - last_timestamp;
 
     // Precision changes from nanosecond to millisecond.
@@ -469,7 +465,7 @@ TEST_F(WebRtcVideoEngine2Test, PropagatesInputFrameTimestamp) {
   last_timestamp = stream->GetLastTimestamp();
   for (int i = 0; i < 10; i++) {
     EXPECT_TRUE(capturer.CaptureFrame());
-    timestamp = stream->GetLastTimestamp();
+    int64_t timestamp = stream->GetLastTimestamp();
     int64_t interval = timestamp - last_timestamp;
 
     // Precision changes from nanosecond to millisecond.
@@ -483,6 +479,64 @@ TEST_F(WebRtcVideoEngine2Test, PropagatesInputFrameTimestamp) {
   EXPECT_TRUE(channel->RemoveSendStream(kSsrc));
 }
 
+TEST_F(WebRtcVideoEngine2Test,
+       ProducesIncreasingTimestampsWithResetInputSources) {
+  cricket::FakeWebRtcVideoEncoderFactory encoder_factory;
+  encoder_factory.AddSupportedVideoCodecType(webrtc::kVideoCodecVP8, "VP8");
+  std::vector<cricket::VideoCodec> codecs;
+  codecs.push_back(kVp8Codec);
+
+  FakeCallFactory factory;
+  engine_.SetCallFactory(&factory);
+  rtc::scoped_ptr<VideoMediaChannel> channel(
+      SetUpForExternalEncoderFactory(&encoder_factory, codecs));
+
+  EXPECT_TRUE(
+      channel->AddSendStream(cricket::StreamParams::CreateLegacy(kSsrc)));
+  channel->SetSend(true);
+  FakeVideoSendStream* stream = factory.GetCall()->GetVideoSendStreams()[0];
+
+  FakeVideoCapturer capturer1;
+  EXPECT_TRUE(channel->SetCapturer(kSsrc, &capturer1));
+
+  cricket::CapturedFrame frame;
+  frame.width = 1280;
+  frame.height = 720;
+  frame.fourcc = cricket::FOURCC_I420;
+  frame.data_size = static_cast<uint32>(
+      cricket::VideoFrame::SizeOf(frame.width, frame.height));
+  rtc::scoped_ptr<char[]> data(new char[frame.data_size]);
+  frame.data = data.get();
+  memset(frame.data, 1, frame.data_size);
+  frame.elapsed_time = 0;
+  const int kInitialTimestamp = 123456;
+  frame.time_stamp = kInitialTimestamp;
+
+  // Deliver initial frame.
+  capturer1.SignalCapturedFrame(&frame);
+  // Deliver next frame 1 second later.
+  frame.time_stamp += rtc::kNumNanosecsPerSec;
+  rtc::Thread::Current()->SleepMs(1000);

[pthatcher1, 2015/09/17 05:00:31]

If you have to do a real sleep, can you at least make it shorter?

[pbos-webrtc, 2015/09/17 06:36:20]

It's a bit longer due to incoming frames being stamped with a real clock which
can't be injected and I didn't want this test to flakily pass on slower bots if
there is a bug because threads are scheduled to run later.

+  capturer1.SignalCapturedFrame(&frame);
+
+  int64_t capturer1_last_timestamp = stream->GetLastTimestamp();
+  // Reset input source, should still be continuous even though input-frame
+  // timestamp is less than before.
+  FakeVideoCapturer capturer2;
+  EXPECT_TRUE(channel->SetCapturer(kSsrc, &capturer2));
+
+  rtc::Thread::Current()->SleepMs(1);
+  // Deliver with a timestamp (10 seconds) before the previous initial one,
+  // these should not be related at all anymore and it should still work fine.
+  frame.time_stamp = kInitialTimestamp - 10000;
+  capturer2.SignalCapturedFrame(&frame);
+
+  // New timestamp should be at least 1ms in the future and not old.
+  EXPECT_GT(stream->GetLastTimestamp(), capturer1_last_timestamp);
+
+  EXPECT_TRUE(channel->RemoveSendStream(kSsrc));
+}
+
 VideoMediaChannel* WebRtcVideoEngine2Test::SetUpForExternalEncoderFactory(
     cricket::WebRtcVideoEncoderFactory* encoder_factory,
     const std::vector<VideoCodec>& codecs) {