Fix calculation for when to send a keepalive image. Possible fixes #4101

Author: connortechnology

src/zm_eventstream.cpp

@@ -940,12 +940,13 @@ void EventStream::runStream() {
   Microseconds delta = Microseconds(0);
 
   while (!zm_terminate) {
-    start = std::chrono::steady_clock::now();
+    now = start = std::chrono::steady_clock::now();
 
     {
       std::scoped_lock lck{mutex};
 
       send_frame = false;
+      TimePoint::duration time_since_last_send = now - last_frame_sent;
 
       if (!paused) {
         // Figure out if we should send this frame
@@ -964,16 +965,22 @@ void EventStream::runStream() {
         send_frame = true;
       } else if (!send_frame) {
         // We are paused, not stepping and doing nothing, meaning that comms didn't set send_frame to true
-        if (now - last_frame_sent > MAX_STREAM_DELAY) {
+        if (time_since_last_send > MAX_STREAM_DELAY) {
           // Send keepalive
           Debug(2, "Sending keepalive frame");
           send_frame = true;
+        } else {
+          Debug(4, "Not Sending keepalive frame now %.2f - %.2f last = %.2f > Max %.2f",
+              FPSeconds(now.time_since_epoch()).count(),
+              FPSeconds(last_frame_sent.time_since_epoch()).count(),
+              FPSeconds(time_since_last_send).count(),
+              FPSeconds(MAX_STREAM_DELAY).count()
+              );
         }
       }  // end if streaming stepping or doing nothing
 
       // time_to_event > 0 means that we are not in the event
       if (time_to_event > Seconds(0) and mode == MODE_ALL) {
-        TimePoint::duration time_since_last_send = now - last_frame_sent;
         Debug(1, "Time since last send = %.2f s", FPSeconds(time_since_last_send).count());
         if (time_since_last_send > Seconds(1)) {
           char frame_text[64];
@@ -1069,8 +1076,7 @@ void EventStream::runStream() {
                   base_fps,
                   effective_fps);
           }
-          now = std::chrono::steady_clock::now();
-          TimePoint::duration elapsed = now - start;
+          TimePoint::duration elapsed = std::chrono::steady_clock::now() - start;
           delta -= std::chrono::duration_cast<Microseconds>(elapsed); // sending frames takes time, so remove it from the sleep time
 
           Debug(2, "New delta: %fs from last frame offset %fs - next_frame_offset %fs - elapsed %fs",