Verify startup codec preparation keeps GUI responsive and reuses probes

tools/chatgui/tests/test_call_video_clock.cpp

@@ -25,10 +25,15 @@ static int64_t start;
 static bool disturbed = false;
 static bool slowDecoder = false, holdAck = false, limitedDisplay = false;
 static std::atomic<unsigned> decodedFrames{0};
+static std::atomic<unsigned> codecOpens{0};
 static std::atomic<size_t> displayThread{0};
 static std::atomic<bool> unsafeTimer{false};
 static size_t threadId() { return std::hash<std::thread::id>{}(std::this_thread::get_id()); }
 static int64_t nowUs() { return std::chrono::duration_cast<std::chrono::microseconds>(std::chrono::steady_clock::now().time_since_epoch()).count(); }
+extern "C" int __real_avcodec_open2(AVCodecContext*, const AVCodec*, AVDictionary**);
+extern "C" int __wrap_avcodec_open2(AVCodecContext* context, const AVCodec* codec, AVDictionary** options) {
+    ++codecOpens; return __real_avcodec_open2(context, codec, options);
+}
 extern "C" int __real_avcodec_receive_frame(AVCodecContext*, AVFrame*);
 extern "C" int __wrap_avcodec_receive_frame(AVCodecContext* codec, AVFrame* frame) {
     if (threadId() == displayThread.load()) unsafeTimer = true;
@@ -110,6 +115,27 @@ static bool queuePressure() {
 int main(int argc, char** argv) {
     QCoreApplication app(argc, argv); debug_config_init(); debug_set_level(DEBUG_LEVEL_WARN);
     debug_set_category_level(DEBUG_CATEGORY_CALL, DEBUG_LEVEL_DEBUG);
+    // Как при старте GUI: подготовка в worker, event loop работает, повторный вызов не открывает codec.
+    std::atomic<bool> preparing{true}, prepared{false};
+    call_video_caps ready{};
+    std::thread warmup([&] { ready = CallVideoEngine::capabilities(&preparing); prepared = true; });
+    QTimer pulse; pulse.setInterval(10); unsigned ticks = 0;
+    QObject::connect(&pulse, &QTimer::timeout, [&] { ++ticks; }); pulse.start();
+    const int64_t warming = nowUs();
+    while (!prepared && nowUs() - warming < 10000000) { app.processEvents(); QThread::msleep(1); }
+    preparing = false; warmup.join(); pulse.stop();
+    if (!ticks || !ready.decode[0].profiles || !ready.decode[1].profiles || !codecOpens) return 1;
+    const unsigned opened = codecOpens;
+    const auto cancelled = CallVideoEngine::capabilities(&preparing);
+    if (cancelled.encode[0].profiles || cancelled.decode[0].profiles) return 1;
+    for (int i = 0; i < 3; ++i) {
+        const auto cached = CallVideoEngine::capabilities();
+        uint8_t expected[CALL_VIDEO_CAPS_BYTES], actual[CALL_VIDEO_CAPS_BYTES];
+        if (call_video_caps_encode(&ready, expected) || call_video_caps_encode(&cached, actual)
+            || memcmp(expected, actual, sizeof(actual)) || codecOpens != opened) return 1;
+    }
+    DEBUG_INFO(DEBUG_CATEGORY_CALL, "PASS video background preparation elapsed_us=%lld gui_ticks=%u codec_opens=%u; "
+        "cancelled access preserves cache, three warm accesses open no codecs", (long long)(nowUs() - warming), ticks, opened);
     if (!queuePressure()) return 1;
     CallVideoEncoder encoder; if (!encoder.open(format, 1000000, "libx264")) return 2;
     QImage image(640, 360, QImage::Format_RGB32); image.fill(Qt::blue);