diff --git a/tools/chatgui/CMakeLists.txt b/tools/chatgui/CMakeLists.txt
index 3265cf5d..937ddbf0 100644
--- a/tools/chatgui/CMakeLists.txt
+++ b/tools/chatgui/CMakeLists.txt
@@ -181,3 +181,22 @@ add_executable(test_config_updater
 target_include_directories(test_config_updater PRIVATE ${CMAKE_SOURCE_DIR})
 target_link_libraries(test_config_updater PRIVATE ${QT_CORE} pthread)
 add_test(NAME test_config_updater COMMAND test_config_updater)
+
+# smoke-тест видео-декодера (FFmpeg). Ручной запуск: test_video_engine <mp4>
+add_executable(test_video_engine
+    tests/test_video_engine.cpp
+    src/videoplayer_engine.cpp
+    src/sound_manager.cpp
+    transport/miniaudio_impl.c
+)
+target_include_directories(test_video_engine PRIVATE ${CMAKE_SOURCE_DIR}/../../lib ${CMAKE_SOURCE_DIR}/../../src ${CMAKE_SOURCE_DIR}/db ${CMAKE_SOURCE_DIR}/../../lib/libopus/include ${FFMPEG_INCLUDE_DIRS})
+target_compile_definitions(test_video_engine PRIVATE USE_SQLITE SQLITE_THREADSAFE=1)
+if(FFMPEG_FOUND)
+    target_compile_definitions(test_video_engine PRIVATE HAVE_FFMPEG)
+endif()
+set_source_files_properties(transport/miniaudio_impl.c PROPERTIES LANGUAGE C)
+if(WIN32)
+    target_link_libraries(test_video_engine PRIVATE ${QT_LIBS} ${QT_CORE} utun pthread ${FFMPEG_TARGET} ${FFMPEG_LIBRARIES})
+else()
+    target_link_libraries(test_video_engine PRIVATE ${QT_LIBS} ${QT_CORE} utun pthread dl ${FFMPEG_TARGET} ${FFMPEG_LIBRARIES})
+endif()
diff --git a/tools/chatgui/src/videoplayer_engine.cpp b/tools/chatgui/src/videoplayer_engine.cpp
index 2885d5ff..3ac826f7 100644
--- a/tools/chatgui/src/videoplayer_engine.cpp
+++ b/tools/chatgui/src/videoplayer_engine.cpp
@@ -357,6 +357,8 @@ void VideoPlayerEngine::close() {
 
 qint64 VideoPlayerEngine::clockMs() const {
     if (m_hasAudio && m_audioSampleRate > 0) {
+        if (m_state == Finished && !SoundManager::instance()->isCurrentPcmPlaying())
+            return m_durationMs;  /* аудио закончилось — часы в конец */
         unsigned long long cur = SoundManager::instance()->currentPcmCursor();
         return (qint64)(cur * 1000 / (unsigned long long)m_audioSampleRate);
     }
@@ -393,7 +395,14 @@ void VideoPlayerEngine::onAudioDecoded(std::shared_ptr<std::vector<int16_t>> pcm
         m_audioSampleRate = sampleRate;
         SoundManager::instance()->playRawPcm(pcm->data(), (int)(pcm->size() / (size_t)channels),
                                              sampleRate, channels);
-        DEBUG_DEBUG(DEBUG_CATEGORY_VIDEO, "VideoEngine: audio started %dHz %dch", sampleRate, channels);
+        if (!SoundManager::instance()->isCurrentPcmPlaying()) {
+            /* аудио-устройство недоступно — переходим на системные часы */
+            m_hasAudio = false;
+            m_audioSampleRate = 0;
+            DEBUG_WARN(DEBUG_CATEGORY_VIDEO, "VideoEngine: audio not playing, fallback to system clock");
+        } else {
+            DEBUG_DEBUG(DEBUG_CATEGORY_VIDEO, "VideoEngine: audio started %dHz %dch", sampleRate, channels);
+        }
     } else {
         m_hasAudio = false;
         DEBUG_WARN(DEBUG_CATEGORY_VIDEO, "VideoEngine: no audio data, video only");
@@ -426,25 +435,24 @@ void VideoPlayerEngine::onWorkerFinished() {
 
 void VideoPlayerEngine::presentTick() {
     qint64 clk = clockMs();
+    if (m_durationMs > 0 && clk > m_durationMs) clk = m_durationMs;
+
     QImage show;
     bool have = false;
-    while (!m_pending.empty()) {
-        if (m_state != Finished && m_pending.front().second > clk) break;
+    while (!m_pending.empty() && m_pending.front().second <= clk) {
         show = m_pending.front().first;
         m_pending.pop_front();
         have = true;
     }
     if (have) { m_renderFrame = show; emit framePresented(); }
 
+    m_positionMs = clk;
+    emit positionChanged(m_positionMs);
+
     if (m_state == Finished && m_pending.empty()) {
-        m_positionMs = m_durationMs > 0 ? m_durationMs : clk;
-        emit positionChanged(m_positionMs);
         m_presentTimer.stop();
-        return;
+        if (m_hasAudio) SoundManager::instance()->stopCurrentPcm();
     }
-    m_positionMs = clk;
-    if (m_durationMs > 0 && clk > m_durationMs) m_positionMs = m_durationMs;
-    emit positionChanged(m_positionMs);
 }
 
 #include "videoplayer_engine.moc"
diff --git a/tools/chatgui/src/videoplayer_window.cpp b/tools/chatgui/src/videoplayer_window.cpp
index 20654824..3d85fd7a 100644
--- a/tools/chatgui/src/videoplayer_window.cpp
+++ b/tools/chatgui/src/videoplayer_window.cpp
@@ -11,6 +11,7 @@
 #include <QKeyEvent>
 #include <QMouseEvent>
 #include <QCloseEvent>
+#include <QResizeEvent>
 #include <QApplication>
 #include <QScreen>
 #include <QStyle>
@@ -298,3 +299,11 @@ void VideoPlayerWindow::closeEvent(QCloseEvent* e) {
     emit closed();
     QWidget::closeEvent(e);
 }
+
+void VideoPlayerWindow::resizeEvent(QResizeEvent* e) {
+    QWidget::resizeEvent(e);
+    m_render->setGeometry(rect());
+    int ch = 48;
+    m_controls->setGeometry(0, height() - ch, width(), ch);
+    m_controls->raise();
+}
diff --git a/tools/chatgui/src/videoplayer_window.h b/tools/chatgui/src/videoplayer_window.h
index 8d09d10e..dc35c52f 100644
--- a/tools/chatgui/src/videoplayer_window.h
+++ b/tools/chatgui/src/videoplayer_window.h
@@ -46,6 +46,7 @@ protected:
     void mouseReleaseEvent(QMouseEvent* event) override;
     void mouseDoubleClickEvent(QMouseEvent* event) override;
     void closeEvent(QCloseEvent* event) override;
+    void resizeEvent(QResizeEvent* event) override;
 
 private slots:
     void onEngineOpened(int width, int height, qint64 durationMs, bool hasAudio);
diff --git a/tools/chatgui/tests/test_video_engine.cpp b/tools/chatgui/tests/test_video_engine.cpp
new file mode 100644
index 00000000..1b04418f
--- /dev/null
+++ b/tools/chatgui/tests/test_video_engine.cpp
@@ -0,0 +1,47 @@
+// tests/test_video_engine.cpp — smoke-тест декодера VideoPlayerEngine (FFmpeg)
+// Запуск: test_video_engine <путь_к_mp4>
+#include "../src/videoplayer_engine.h"
+#include <QApplication>
+#include <QTimer>
+#include <QEventLoop>
+#include <QDebug>
+#include <cstdio>
+
+int main(int argc, char** argv) {
+    QApplication app(argc, argv);
+    if (argc < 2) { qCritical("usage: test_video_engine <video.mp4>"); return 2; }
+    QString path = argv[1];
+
+    VideoPlayerEngine eng;
+    int frames = 0, opened = 0, errors = 0, finished = 0;
+    qint64 lastPos = -1;
+    int width = 0, height = 0; qint64 dur = 0; bool hasAudio = false;
+
+    QObject::connect(&eng, &VideoPlayerEngine::opened,
+                     [&](int w, int h, qint64 d, bool a) { opened++; width = w; height = h; dur = d; hasAudio = a; });
+    QObject::connect(&eng, &VideoPlayerEngine::framePresented, [&]() { frames++; });
+    QObject::connect(&eng, &VideoPlayerEngine::positionChanged, [&](qint64 p) { lastPos = p; });
+    QObject::connect(&eng, &VideoPlayerEngine::error, [&](const QString& m) { errors++; qCritical("engine error: %s", qPrintable(m)); });
+    QObject::connect(&eng, &VideoPlayerEngine::finished, [&]() { finished++; });
+
+    eng.open(path);
+
+    QEventLoop loop;
+    QTimer timer;
+    timer.setSingleShot(true);
+    QObject::connect(&timer, &QTimer::timeout, &loop, &QEventLoop::quit);
+    timer.start(5000);
+    loop.exec();
+
+    eng.close();
+
+    qInfo("opened=%d (%dx%d dur=%lldms audio=%d) frames=%d finished=%d errors=%d lastPos=%lldms",
+          opened, width, height, (long long)dur, hasAudio ? 1 : 0, frames, finished, errors, (long long)lastPos);
+
+    int rc = 0;
+    if (opened != 1) { qCritical("FAIL: opened != 1"); rc = 1; }
+    if (frames <= 0) { qCritical("FAIL: no frames presented"); rc = 1; }
+    if (errors > 0) { qCritical("FAIL: errors present"); rc = 1; }
+    qInfo(rc == 0 ? "PASS" : "FAIL");
+    return rc;
+}