Add periodic logging of number of captured and dropped frames in VideoCaptureInput.

webrtc/video/video_capture_input.cc

Index: webrtc/video/video_capture_input.cc
diff --git a/webrtc/video/video_capture_input.cc b/webrtc/video/video_capture_input.cc
index 8f574e21154d7abddca59dcf46b28d476866d5dc..7777f45b220ebcfde66bfc4ffffb491c48abb7dc 100644
--- a/webrtc/video/video_capture_input.cc
+++ b/webrtc/video/video_capture_input.cc
@@ -21,6 +21,9 @@
 #include "webrtc/video/vie_encoder.h"
 
 namespace webrtc {
+namespace {
+const int64_t kFrameLogIntervalMs = 60000;
+}  // namespace
 
 namespace internal {
 VideoCaptureInput::VideoCaptureInput(
@@ -38,7 +41,10 @@ VideoCaptureInput::VideoCaptureInput(
       last_captured_timestamp_(0),
       delta_ntp_internal_ms_(clock_->CurrentNtpInMilliseconds() -
                              clock_->TimeInMilliseconds()),
-      overuse_detector_(overuse_detector) {}
+      overuse_detector_(overuse_detector),
+      last_frame_log_ms_(clock_->TimeInMilliseconds()),
+      captured_frame_count_(0),
+      dropped_frame_count_(0) {}
 
 VideoCaptureInput::~VideoCaptureInput() {
 }
@@ -83,6 +89,10 @@ void VideoCaptureInput::IncomingCapturedFrame(const VideoFrame& video_frame) {
     return;
   }
 
+  ++captured_frame_count_;
+  if (captured_frame_.get())
+    ++dropped_frame_count_;
+
   captured_frame_.reset(new VideoFrame);
   captured_frame_->ShallowCopy(incoming_frame);
   last_captured_timestamp_ = incoming_frame.ntp_time_ms();
@@ -92,6 +102,12 @@ void VideoCaptureInput::IncomingCapturedFrame(const VideoFrame& video_frame) {
   TRACE_EVENT_ASYNC_BEGIN1("webrtc", "Video", video_frame.render_time_ms(),
                            "render_time", video_frame.render_time_ms());
 
+  if (current_time - last_frame_log_ms_ > kFrameLogIntervalMs) {
+    last_frame_log_ms_ = current_time;
+    LOG(LS_INFO) << "Number of frames: captured " << captured_frame_count_

[mflodman, 2016/09/02 08:46:02]

I'd prefer to log the number of frames for the last minute, then restart from
zero to make it easier to compare log lines in test for longer calls. 

Mats,
wdyt? 

[mnilsson, 2016/09/02 09:21:10]

Yes, resetting the count will make it easier to see the behavior for the last
window. We can also more easily aggregate several windows for a longer average.

[åsapersson, 2016/09/02 10:19:43]

Done.

[åsapersson, 2016/09/02 10:19:43]

Done.

+                 << ", dropped " << dropped_frame_count_;
+  }
+
   capture_event_->Set();
 }