Fix viewing fps display by keeping track of last update time, last frame count and actually calculate it based on frames sent over a period of time.

src/zm_monitorstream.cpp

@@ -265,7 +265,14 @@ void MonitorStream::processCommand(const CmdMsg *msg) {
     status_data.forced = false;
     status_data.buffer_level = 0;
   } else {
-    status_data.fps = monitor->GetFPS();
+    FPSeconds elapsed = now - last_fps_update;
+    if (elapsed.count()) { 
+      actual_fps = (frame_count - last_frame_count) / elapsed.count();
+      last_frame_count = frame_count;
+      last_fps_update = now;
+    }
+
+    status_data.fps = actual_fps;
     status_data.capture_fps = monitor->get_capture_fps();
     status_data.analysis_fps = monitor->get_analysis_fps();
     status_data.state = monitor->shared_data->state;
@@ -558,10 +565,9 @@ void MonitorStream::runStream() {
     }
   } else {
     Debug(2, "Not using playback_buffer");
-  } // end if connkey  & playback_buffer
+  } // end if connkey && playback_buffer
 
   while (!zm_terminate) {
-    bool got_command = false;
     if (feof(stdout)) {
       Debug(2, "feof stdout");
       break;
@@ -576,6 +582,7 @@ void MonitorStream::runStream() {
     now = std::chrono::system_clock::now();
 
     bool was_paused = paused;
+    bool got_command = false; // commands like zoom should output a frame even if paused
     if (connkey) {
       while (checkCommandQueue() && !zm_terminate) {
         // Loop in here until all commands are processed.
@@ -597,7 +604,6 @@ void MonitorStream::runStream() {
         paused_timestamp = SystemTimePoint(zm::chrono::duration_cast<Microseconds>(monitor->shared_timestamps[index]));
       }
     } else if (paused_image) {
-      Debug(1, "Clearing paused_image");
       delete paused_image;
       paused_image = nullptr;
     }
@@ -606,15 +612,12 @@ void MonitorStream::runStream() {
       if (temp_read_index == temp_write_index) {
         // Go back to live viewing
         Debug(1, "Exceeded temporary streaming buffer");
-        // Clear paused flag
         paused = false;
-        // Clear delayed_play flag
         delayed = false;
         replay_rate = ZM_RATE_BASE;
       } else {
         if (!paused) {
           int temp_index = MOD_ADD(temp_read_index, 0, temp_image_buffer_count);
-          // Debug( 3, "tri: %d, ti: %d", temp_read_index, temp_index );
           SwapImage *swap_image = &temp_image_buffer[temp_index];
 
           if (!swap_image->valid) {
@@ -628,7 +631,7 @@ void MonitorStream::runStream() {
             // If the next frame is due
             if (actual_delta_time > expected_delta_time) {
               // Debug( 2, "eDT: %.3lf, aDT: %.3f", expected_delta_time, actual_delta_time );
-              if (temp_index % frame_mod == 0) {
+              if ((temp_index % frame_mod) == 0) {
                 Debug(2, "Sending delayed frame %d", temp_index);
                 // Send the next frame
                 if (!sendFrame(temp_image_buffer[temp_index].file_name, temp_image_buffer[temp_index].timestamp)) {
@@ -646,7 +649,10 @@ void MonitorStream::runStream() {
           SwapImage *swap_image = &temp_image_buffer[temp_read_index];
 
           // Send the next frame
-          if (!sendFrame(temp_image_buffer[temp_read_index].file_name, temp_image_buffer[temp_read_index].timestamp)) {
+          if (!sendFrame(
+                temp_image_buffer[temp_read_index].file_name,
+                temp_image_buffer[temp_read_index].timestamp)
+              ) {
             zm_terminate = true;
           }
 
@@ -682,7 +688,7 @@ void MonitorStream::runStream() {
 
     if (last_read_index != monitor->shared_data->last_write_index) {
       // have a new image to send
-      int index = monitor->shared_data->last_write_index % monitor->image_buffer_count; // % shouldn't be neccessary
+      int index = monitor->shared_data->last_write_index % monitor->image_buffer_count;
       if ((frame_mod == 1) || ((frame_count%frame_mod) == 0)) {
         if (!paused && !delayed) {
           last_read_index = monitor->shared_data->last_write_index;
@@ -700,8 +706,6 @@ void MonitorStream::runStream() {
             zm_terminate = true;
             break;
           }
-          //frame_sent = true;
-          //
           if (frame_count == 0) {
             // Chrome will not display the first frame until it receives another.
             // Firefox is fine.  So just send the first frame twice.
@@ -801,7 +805,7 @@ void MonitorStream::runStream() {
       Warning("no last_frame_sent.  Shouldn't happen. frame_mod was (%d) frame_count (%d)",
           frame_mod, frame_count);
     }
-  } // end while
+  } // end while ! zm_terminate
 
   if (buffered_playback) {
     Debug(1, "Cleaning swap files from %s", swap_path.c_str());

src/zm_monitorstream.h

@@ -40,7 +40,6 @@ class MonitorStream : public StreamBase {
     Microseconds ttl;
     int playback_buffer;
     bool delayed;
-    int frame_count;
 
   protected:
     bool checkSwapPath(const char *path, bool create_path);
@@ -61,8 +60,8 @@ class MonitorStream : public StreamBase {
       temp_write_index(0),
       ttl(0),
       playback_buffer(0),
-      delayed(false),
-      frame_count(0) {}
+      delayed(false)
+  {}
 
     void setStreamBuffer(int p_playback_buffer) {
       playback_buffer = p_playback_buffer;

src/zm_stream.h

@@ -102,7 +102,6 @@ protected:
   int last_scale;
   int zoom;
   int last_zoom;
-  double maxfps;
   int bitrate;
   unsigned short last_x, last_y;
   unsigned short x, y;
@@ -122,8 +121,14 @@ protected:
   SystemTimePoint now;
   SystemTimePoint last_comm_update;
 
-  double base_fps;
-  double effective_fps;
+  double maxfps;
+  double base_fps;        // Should be capturing fps, hence a rough target
+  double effective_fps;   // Target fps after taking max_fps into account
+  double actual_fps;      // sliding calculated actual streaming fps achieved
+  SystemTimePoint last_fps_update;
+  int frame_count;      // Count of frames sent
+  int last_frame_count; // Used in calculating actual_fps from frame_count - last_frame_count
+
   int frame_mod;
 
   SystemTimePoint last_frame_sent;
@@ -152,7 +157,6 @@ public:
     last_scale(DEFAULT_SCALE),
     zoom(DEFAULT_ZOOM),
     last_zoom(DEFAULT_ZOOM),
-    maxfps(DEFAULT_MAXFPS),
     bitrate(DEFAULT_BITRATE),
     last_x(0),
     last_y(0),
@@ -164,7 +168,14 @@ public:
     sd(-1),
     lock_fd(0),
     paused(false),
-    step(0)
+    step(0),
+    maxfps(DEFAULT_MAXFPS),
+    base_fps(0.0),
+    effective_fps(0.0),
+    actual_fps(0.0),
+    frame_count(0),
+    last_frame_count(0),
+    frame_mod(1)
   {
     memset(&loc_sock_path, 0, sizeof(loc_sock_path));
     memset(&loc_addr, 0, sizeof(loc_addr));
@@ -172,10 +183,6 @@ public:
     memset(&rem_addr, 0, sizeof(rem_addr));
     memset(&sock_path_lock, 0, sizeof(sock_path_lock));
 
-    base_fps = 0.0;
-    effective_fps = 0.0;
-    frame_mod = 1;
-
     vid_stream = nullptr;
     msg = { 0, { 0 } };
   }