Preserve desktop camera cadence under timestamp jitter

tools/chatgui/src/call_video_engine.cpp

@@ -1,6 +1,7 @@
 #include "call_video_engine.h"
 #include "call_video_encoder.h"
 #include "call_video_decoder.h"
+#include "call_video_cadence.h"
 #include "../../../src/call/call_video_port.h"
 #include "../../../src/call/call_audio.h"
 #include "debug_config.h"
@@ -174,7 +175,7 @@ void CallVideoEngine::transmit() {
     int64_t reportAt = nowUs(), encodeMax = 0;
     uint64_t captureBase = 0;
     unsigned encodedCount = 0, keyCount = 0, sendBusy = 0, paced = 0;
-    int64_t pacedPts = -1;
+    CallVideoCadence cadence;
     while (m->running) {
         struct call_video_port_status state{};
         if (call_video_port_status(m->id, &state) < 0) break;
@@ -210,10 +211,6 @@ void CallVideoEngine::transmit() {
         }
         if (format.generation && state.have_peer && !call_video_format_supported(&caps, &state.peer, &format)) appliedRevision = 0;
         if (!enabled || !state.have_peer || pts <= lastPts) { idle(); continue; }
-        if (lastPts >= 0 && pts - lastPts < 33333) {
-            if (pacedPts != pts) { pacedPts = pts; ++paced; }
-            idle(); continue;
-        }
         if (revision != appliedRevision) {
             if (lastKey >= 0 && pts - lastKey < 1000000) { idle(); continue; }
             call_video_format next{format.generation + 1, (uint16_t)width, (uint16_t)height, 30, 0, (uint8_t)codec, 0, 4000000, 0};
@@ -243,6 +240,7 @@ void CallVideoEngine::transmit() {
                 call_video_port_applied(m->id, format.generation, request, 0);
         }
 #ifdef HAVE_STREAM_CAPTURE
+        if (!cadence.accept(pts)) { lastPts = pts; ++paced; idle(); continue; }
         QImage image = raw.toImage();
         if (image.isNull()) { DEBUG_WARN(DEBUG_CATEGORY_CALL, "camera frame conversion failed"); lastPts = pts; continue; }
         LiveEncodedFrame output; CallVideoRateCompletion completion;