diff --git a/tools/chatgui/src/stream_publish_engine.cpp b/tools/chatgui/src/stream_publish_engine.cpp
index d517c02f..2d4002d0 100644
--- a/tools/chatgui/src/stream_publish_engine.cpp
+++ b/tools/chatgui/src/stream_publish_engine.cpp
@@ -7,6 +7,7 @@
 #include <QScreen>
 #include <QRandomGenerator>
 #include <QTransform>
+#include <QPixmap>
 #include <QJsonArray>
 #include <QJsonDocument>
 #include <thread>
@@ -73,6 +74,7 @@ struct StreamPublishEngine::Impl {
     std::unique_ptr<QVideoSink> sink;
     std::unique_ptr<QCamera> camera;
     std::unique_ptr<QScreenCapture> screen;
+    std::unique_ptr<QTimer> screenGrabTimer;
     std::unique_ptr<QWindowCapture> window;
     QVideoFrame frame;
     QVideoFrame previewFrame;
@@ -239,21 +241,55 @@ bool StreamPublishEngine::openSource(const StreamPublishConfig& config) {
         connect(m->camera.get(), &QCamera::errorOccurred, this, [failed](QCamera::Error, const QString& error) { failed(error); }, Qt::QueuedConnection);
         m->camera->start();
     } else if (config.source.kind == StreamVideoSource::Screen) {
-        m->screen = std::make_unique<QScreenCapture>();
+        QScreen* selected = nullptr;
         if (config.source.id != "portal") {
-            QScreen* selected = nullptr;
             for (auto* screen : QGuiApplication::screens())
                 if (screen == config.source.screen && screenId(screen) == config.source.id) { selected = screen; break; }
             if (!selected) { DEBUG_ERROR(DEBUG_CATEGORY_VIDEO, "desktop screen disappeared"); return false; }
+        }
+        // Qt X11 screen capture ищет root по имени и путает мониторы; QScreen захватывает именно выбранный экран.
+        if (selected && QGuiApplication::platformName() == "xcb") {
+            m->screenGrabTimer = std::make_unique<QTimer>(); m->screenGrabTimer->setTimerType(Qt::PreciseTimer);
+            connect(m->screenGrabTimer.get(), &QTimer::timeout, this, [this, generation, screen = QPointer<QScreen>(selected), failed] {
+                if (generation != m->sourceGeneration || !m->running) return;
+                int64_t captured = monotonicUs();
+                QImage image = screen ? screen->grabWindow(0).toImage() : QImage();
+                if (image.isNull()) {
+                    DEBUG_ERROR(DEBUG_CATEGORY_VIDEO, "desktop X11 screen grab failed present=%d", !screen.isNull());
+                    m->screenGrabTimer->stop();
+                    QMetaObject::invokeMethod(this, [failed] { failed(text("Video capture stopped")); }); return;
+                }
+#if QT_VERSION >= QT_VERSION_CHECK(6, 8, 0)
+                QVideoFrame frame(image);
+#else
+                image = image.convertToFormat(QImage::Format_RGBA8888);
+                QVideoFrame frame(QVideoFrameFormat(image.size(), QVideoFrameFormat::Format_RGBA8888));
+                if (frame.map(QVideoFrame::WriteOnly)) {
+                    for (int y = 0; y < image.height(); y++) std::memcpy(frame.bits(0) + y * frame.bytesPerLine(0), image.constScanLine(y), image.width() * 4);
+                    frame.unmap();
+                } else frame = {};
+#endif
+                if (!frame.isValid()) {
+                    DEBUG_ERROR(DEBUG_CATEGORY_VIDEO, "desktop X11 video frame allocation failed size=%dx%d", image.width(), image.height());
+                    m->screenGrabTimer->stop();
+                    QMetaObject::invokeMethod(this, [failed] { failed(text("Video frame conversion failed")); }); return;
+                }
+                frame.setStartTime(captured); m->sink->setVideoFrame(frame);
+            });
+            m->screenGrabTimer->start(std::max(1, 1000 / std::clamp(config.video.fps, 1, 60)));
+            DEBUG_INFO(DEBUG_CATEGORY_VIDEO, "desktop X11 screen grab started source=%s interval_ms=%d",
+                qPrintable(config.source.name), m->screenGrabTimer->interval());
+        } else {
+            m->screen = std::make_unique<QScreenCapture>();
             m->screen->setScreen(selected);
+            m->session->setScreenCapture(m->screen.get());
+            connect(m->screen.get(), &QScreenCapture::activeChanged, this, [this, generation](bool active) {
+                DEBUG_INFO(DEBUG_CATEGORY_VIDEO, "desktop screen capture active=%d generation=%llu", active, (unsigned long long)generation);
+                if (!active && generation == m->sourceGeneration) sourceFailed(m->generation, text("Video capture stopped"));
+            }, Qt::QueuedConnection);
+            connect(m->screen.get(), &QScreenCapture::errorOccurred, this, [failed](QScreenCapture::Error, const QString& error) { failed(error); }, Qt::QueuedConnection);
+            m->screen->start();
         }
-        m->session->setScreenCapture(m->screen.get());
-        connect(m->screen.get(), &QScreenCapture::activeChanged, this, [this, generation](bool active) {
-            DEBUG_INFO(DEBUG_CATEGORY_VIDEO, "desktop screen capture active=%d generation=%llu", active, (unsigned long long)generation);
-            if (!active && generation == m->sourceGeneration) sourceFailed(m->generation, text("Video capture stopped"));
-        }, Qt::QueuedConnection);
-        connect(m->screen.get(), &QScreenCapture::errorOccurred, this, [failed](QScreenCapture::Error, const QString& error) { failed(error); }, Qt::QueuedConnection);
-        m->screen->start();
     } else {
         auto window = config.source.window.value<QCapturableWindow>();
         if (!window.isValid()) { DEBUG_ERROR(DEBUG_CATEGORY_VIDEO, "desktop window is unavailable"); return false; }
@@ -274,6 +310,7 @@ bool StreamPublishEngine::openSource(const StreamPublishConfig& config) {
 }
 void StreamPublishEngine::closeSource() {
 #ifdef HAVE_STREAM_CAPTURE
+    m->screenGrabTimer.reset();
     emit previewVideoChanged(QVariant());
     if (m->sink) disconnect(m->sink.get(), nullptr, this, nullptr);
     if (m->camera) { disconnect(m->camera.get(), nullptr, this, nullptr); m->camera->stop(); }
@@ -331,6 +368,9 @@ bool StreamPublishEngine::reconfigure(const StreamPublishConfig& config) {
 #endif
     }
     if (sourceChange && !openSource(config)) { sourceFailed(m->generation, text("Could not open the selected video source")); return false; }
+#ifdef HAVE_STREAM_CAPTURE
+    if (m->screenGrabTimer) m->screenGrabTimer->setInterval(std::max(1, 1000 / std::clamp(config.video.fps, 1, 60)));
+#endif
     m->wake.notify_all(); emit stateChanged(text("Applying video settings…")); return true;
 }