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

@@ -255,7 +255,7 @@ void MonitorStream::processCommand(const CmdMsg *msg) {
   } status_data;
 
   status_data.id = monitor->Id();
-  if ( ! monitor->ShmValid() ) {
+  if (!monitor->ShmValid()) {
     status_data.fps = 0.0;
     status_data.capture_fps = 0.0;
     status_data.analysis_fps = 0.0;
@@ -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;
@@ -519,7 +526,7 @@ void MonitorStream::runStream() {
   Image *paused_image = nullptr;
   SystemTimePoint paused_timestamp;
 
-  if ( connkey && ( playback_buffer > 0 ) ) {
+  if (connkey && (playback_buffer > 0)) {
     // 15 is the max length for the swap path suffix, /zmswap-whatever, assuming max 6 digits for monitor id
     const int max_swap_len_suffix = 15;
 
@@ -528,27 +535,27 @@ void MonitorStream::runStream() {
     int subfolder2_length = snprintf(nullptr, 0, "/zmswap-q%06d", connkey) + 1;
     int total_swap_path_length = swap_path_length + subfolder1_length + subfolder2_length;
 
-    if ( total_swap_path_length + max_swap_len_suffix > PATH_MAX ) {
+    if (total_swap_path_length + max_swap_len_suffix > PATH_MAX) {
       Error("Swap Path is too long. %d > %d ", total_swap_path_length+max_swap_len_suffix, PATH_MAX);
     } else {
       swap_path = staticConfig.PATH_SWAP;
 
       Debug(3, "Checking swap path folder: %s", swap_path.c_str());
-      if ( checkSwapPath(swap_path.c_str(), true) ) {
+      if (checkSwapPath(swap_path.c_str(), true)) {
         swap_path += stringtf("/zmswap-m%d", monitor->Id());
 
         Debug(4, "Checking swap path subfolder: %s", swap_path.c_str());
-        if ( checkSwapPath(swap_path.c_str(), true) ) {
+        if (checkSwapPath(swap_path.c_str(), true)) {
           swap_path += stringtf("/zmswap-q%06d", connkey);
 
           Debug(4, "Checking swap path subfolder: %s", swap_path.c_str());
-          if ( checkSwapPath(swap_path.c_str(), true) ) {
+          if (checkSwapPath(swap_path.c_str(), true)) {
             buffered_playback = true;
           }
         }
       }
 
-      if ( !buffered_playback ) {
+      if (!buffered_playback) {
         Error("Unable to validate swap image path, disabling buffered playback");
       } else {
         Debug(2, "Assigning temporary buffer");
@@ -558,14 +565,13 @@ 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)) {
-    if ( feof(stdout) ) {
       Debug(2, "feof stdout");
       break;
-    } else if ( ferror(stdout) ) {
+    } else if (ferror(stdout)) {
       Debug(2, "ferror stdout");
       break;
     } else if (!monitor->ShmValid()) {
@@ -576,8 +582,9 @@ void MonitorStream::runStream() {
     now = std::chrono::system_clock::now();
 
     bool was_paused = paused;
-    if ( connkey ) {
+    bool got_command = false; // commands like zoom should output a frame even if paused
-      while ( checkCommandQueue() && !zm_terminate ) {
+    if (connkey) {
+      while (checkCommandQueue() && !zm_terminate) {
         // Loop in here until all commands are processed.
         Debug(2, "Have checking command Queue for connkey: %d", connkey);
         got_command = true;
@@ -589,35 +596,31 @@ void MonitorStream::runStream() {
       }
     }  // end if connkey
 
-    if ( paused ) {
+    if (paused) {
-      if ( !was_paused ) {
+      if (!was_paused) {
         int index = monitor->shared_data->last_write_index % monitor->image_buffer_count;
         Debug(1, "Saving paused image from index %d",index);
         paused_image = new Image(*monitor->image_buffer[index]);
         paused_timestamp = SystemTimePoint(zm::chrono::duration_cast<Microseconds>(monitor->shared_timestamps[index]));
       }
-    } else if ( paused_image ) {
+    } else if (paused_image) {
-      Debug(1, "Clearing paused_image");
       delete paused_image;
       paused_image = nullptr;
     }
 
-    if ( buffered_playback && delayed ) {
+    if (buffered_playback && delayed) {
-      if ( temp_read_index == temp_write_index ) {
+      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 ) {
+        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 ) {
+          if (!swap_image->valid) {
             paused = true;
             delayed = true;
             temp_read_index = MOD_ADD(temp_read_index, (replay_rate>=0?-1:1), temp_image_buffer_count);
@@ -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;
           }
 
@@ -669,7 +675,7 @@ void MonitorStream::runStream() {
         }  // end if (!paused) or step or paused
       }  // end if have exceeded buffer or not
 
-      if ( temp_read_index == temp_write_index ) {
+      if (temp_read_index == temp_write_index) {
         // Go back to live viewing
         Warning("Rewound over write index, resuming live play");
         // Clear paused flag
@@ -680,11 +686,11 @@ void MonitorStream::runStream() {
       }
     }  // end if ( buffered_playback && delayed )
 
-    if ( last_read_index != monitor->shared_data->last_write_index ) {
+    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 ((frame_mod == 1) || ((frame_count%frame_mod) == 0)) {
-        if ( !paused && !delayed ) {
+        if (!paused && !delayed) {
           last_read_index = monitor->shared_data->last_write_index;
           Debug(2, "Sending frame index: %d: frame_mod: %d frame count: %d paused(%d) delayed(%d)",
               index, frame_mod, frame_count, paused, delayed);
@@ -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.
@@ -714,11 +718,11 @@ void MonitorStream::runStream() {
 
           temp_read_index = temp_write_index;
         } else {
-          if ( delayed && !buffered_playback ) {
+          if (delayed && !buffered_playback) {
             Debug(2, "Can't delay when not buffering.");
             delayed = false;
           }
-          if ( last_zoom != zoom ) {
+          if (last_zoom != zoom) {
             Debug(2, "Sending 2 frames because change in zoom %d ?= %d", last_zoom, zoom);
             if (!sendFrame(paused_image, paused_timestamp))
               zm_terminate = true;
@@ -742,9 +746,9 @@ void MonitorStream::runStream() {
         }  // end if paused or not
       }  // end if should send frame
 
-      if ( buffered_playback && !paused ) {
+      if (buffered_playback && !paused) {
-        if ( monitor->shared_data->valid ) {
+        if (monitor->shared_data->valid) {
-          if ( monitor->shared_timestamps[index].tv_sec ) {
+          if (monitor->shared_timestamps[index].tv_sec) {
             int temp_index = temp_write_index%temp_image_buffer_count;
             Debug(2, "Storing frame %d", temp_index);
             if ( !temp_image_buffer[temp_index].valid ) {
@@ -756,7 +760,7 @@ void MonitorStream::runStream() {
                 SystemTimePoint(zm::chrono::duration_cast<Microseconds>(monitor->shared_timestamps[index]));
             monitor->image_buffer[index]->WriteJpeg(temp_image_buffer[temp_index].file_name, config.jpeg_file_quality);
             temp_write_index = MOD_ADD(temp_write_index, 1, temp_image_buffer_count);
-            if ( temp_write_index == temp_read_index ) {
+            if (temp_write_index == temp_read_index) {
               // Go back to live viewing
               Warning("Exceeded temporary buffer, resuming live play");
               paused = false;
@@ -801,37 +805,37 @@ 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 ) {
+  if (buffered_playback) {
     Debug(1, "Cleaning swap files from %s", swap_path.c_str());
     struct stat stat_buf = {};
-    if ( stat(swap_path.c_str(), &stat_buf) < 0 ) {
+    if (stat(swap_path.c_str(), &stat_buf) < 0) {
-      if ( errno != ENOENT ) {
+      if (errno != ENOENT) {
         Error("Can't stat '%s': %s", swap_path.c_str(), strerror(errno));
       }
-    } else if ( !S_ISDIR(stat_buf.st_mode) ) {
+    } else if (!S_ISDIR(stat_buf.st_mode)) {
       Error("Swap image path '%s' is not a directory", swap_path.c_str());
     } else {
       std::string glob_pattern = stringtf("%s/*.*", swap_path.c_str());
       glob_t pglob;
 
       int glob_status = glob(glob_pattern.c_str(), 0, 0, &pglob);
-      if ( glob_status != 0 ) {
+      if (glob_status != 0) {
-        if ( glob_status < 0 ) {
+        if (glob_status < 0) {
           Error("Can't glob '%s': %s", glob_pattern.c_str(), strerror(errno));
         } else {
           Debug(1, "Can't glob '%s': %d", glob_pattern.c_str(), glob_status);
         }
       } else {
-        for ( unsigned int i = 0; i < pglob.gl_pathc; i++ ) {
+        for (unsigned int i = 0; i < pglob.gl_pathc; i++) {
-          if ( unlink(pglob.gl_pathv[i]) < 0 ) {
+          if (unlink(pglob.gl_pathv[i]) < 0) {
             Error("Can't unlink '%s': %s", pglob.gl_pathv[i], strerror(errno));
           }
         }
       }
       globfree(&pglob);
-      if ( rmdir(swap_path.c_str()) < 0 ) {
+      if (rmdir(swap_path.c_str()) < 0) {
         Error("Can't rmdir '%s': %s", swap_path.c_str(), strerror(errno));
       }
     } // end if checking for swap_path

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),
+      delayed(false)
-      frame_count(0) {}
+  {}
 
     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 maxfps;
-  double effective_fps;
+  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 } };
   }