Clarify GUI ownership and preserve video queue payload lifetime

tools/chatgui/src/call_video_engine.cpp

@@ -53,7 +53,7 @@ struct CallVideoEngine::Impl {
     QByteArray cameraId;
     bool captureActive = false;
     uint64_t captured = 0;
-    std::atomic<uint64_t> publicationEpoch{0}, pendingSerial{0}, ackSerial{0};
+    std::atomic<uint64_t> pendingSerial{0}, ackSerial{0};
     std::atomic<int64_t> presentedAt{0};
     bool presentationDriven = false;
     uint64_t publicationSerial = 0;
@@ -136,7 +136,7 @@ CallVideoEngine::CallVideoEngine(QObject* parent) : QObject(parent), m(std::make
 }
 CallVideoEngine::~CallVideoEngine() { stop(); delete m->guiNotifier; }
 void CallVideoEngine::setPresentationDriven(bool enabled) {
-    std::lock_guard<std::mutex> guard(m->lock); m->presentationDriven = enabled;
+    m->presentationDriven = enabled;
 }
 void CallVideoEngine::imagePresented(quint64 serial) {
     if (!serial || serial != m->pendingSerial.load(std::memory_order_acquire) || serial == m->ackSerial.load()) return;
@@ -158,7 +158,10 @@ void CallVideoEngine::deliverImage() {
         QImage image;
         if (m->publicationVideo) {
             const auto* slot = m->pictures.readSlot();
-            if (!slot) { DEBUG_ERROR(DEBUG_CATEGORY_CALL, "video GUI missing published slot serial=%llu", (unsigned long long)serial); return; }
+            if (!slot) {
+                DEBUG_ERROR(DEBUG_CATEGORY_CALL, "video GUI missing published slot serial=%llu; stopping video", (unsigned long long)serial);
+                stop(); return;
+            }
             image = slot->image;
         }
         const int64_t now = nowUs(), wait = now - queued;
@@ -228,7 +231,7 @@ void CallVideoEngine::stop() {
     if (m->tx.joinable()) m->tx.join();
     if (m->rx.joinable()) m->rx.join();
     if (m->id) call_video_port_close(m->id);
-    ++m->publicationEpoch; m->pendingSerial = 0; m->paintWaitMax = 0;
+    m->pendingSerial = 0; m->paintWaitMax = 0;
     while (const auto* event = m->logEvents.readSlot()) { call_video_playout_log_event(event); m->logEvents.release(); }
     m->id = 0; m->enabled = false; emit imageChanged({}, 0);
 }

tools/chatgui/src/call_video_engine.h

@@ -14,8 +14,8 @@ public:
     void start(quint64 id);
     void stop();
     void setVideo(bool enabled, const QByteArray& camera, int width, int height, int codec);
-    void setPresentationDriven(bool enabled); // Окно подтверждает рисование; без окна достаточно доставки signal.
-    void imagePresented(quint64 serial);
+    void setPresentationDriven(bool enabled); // GUI-поток: окно подтверждает рисование, иначе достаточно доставки signal.
+    void imagePresented(quint64 serial); // GUI-поток; повторный/старый ACK безопасно игнорируется.
 signals:
     void camerasChanged(const CallCameraDevices& devices);
     void imageChanged(const QImage& image, quint64 serial);

tools/chatgui/src/call_video_queue.h

@@ -10,18 +10,18 @@
 template<class T, unsigned Capacity> class CallVideoQueue {
     static_assert(Capacity > 0);
     static_assert(std::atomic<uint64_t>::is_always_lock_free);
-    std::array<T, Capacity> slots{};
+    std::array<T, Capacity> entries{};
     alignas(64) std::atomic<uint64_t> written{0};
     alignas(64) std::atomic<uint64_t> consumed{0};
 public:
     T* writeSlot() {
         const uint64_t tail = written.load(std::memory_order_relaxed);
-        return tail - consumed.load(std::memory_order_acquire) < Capacity ? &slots[tail % Capacity] : nullptr;
+        return tail - consumed.load(std::memory_order_acquire) < Capacity ? &entries[tail % Capacity] : nullptr;
     }
     void publish() { written.fetch_add(1, std::memory_order_release); }
     const T* readSlot() const {
         const uint64_t head = consumed.load(std::memory_order_relaxed);
-        return head < written.load(std::memory_order_acquire) ? &slots[head % Capacity] : nullptr;
+        return head < written.load(std::memory_order_acquire) ? &entries[head % Capacity] : nullptr;
     }
     void release() { consumed.fetch_add(1, std::memory_order_release); }
     // Вызывается только producer/consumer: собственный индекс во время снимка не меняется.
@@ -30,7 +30,7 @@ public:
         return static_cast<unsigned>(written.load(std::memory_order_acquire) - head);
     }
     void reset() {
-        for (auto& slot : slots) slot = {};
+        for (auto& slot : entries) slot = {};
         written.store(0, std::memory_order_relaxed); consumed.store(0, std::memory_order_relaxed);
     }
 };