use OUTPUT_FILENAME constant in all demos

src/beauty/beauty-demo.cpp

@@ -14,6 +14,7 @@ constexpr unsigned long WIDTH = 1920;
 constexpr unsigned long HEIGHT = 1080;
 constexpr double SCALE = 0.125;
 constexpr bool OFFSCREEN = false;
+constexpr const char* OUTPUT_FILENAME = "tetra-demo.mkv";
 constexpr int VA_HW_DEVICE_INDEX = 0;
 constexpr unsigned long DIAG = hypot(double(WIDTH), double(HEIGHT));
 
@@ -196,7 +197,7 @@ int main(int argc, char **argv) {
     }
 
     double fps = capture.get(cv::CAP_PROP_FPS);
-    cv::VideoWriter writer("beauty-demo.mkv", cv::CAP_FFMPEG, cv::VideoWriter::fourcc('V', 'P', '9', '0'), fps, cv::Size(WIDTH, HEIGHT), { cv::VIDEOWRITER_PROP_HW_ACCELERATION, cv::VIDEO_ACCELERATION_VAAPI, cv::VIDEOWRITER_PROP_HW_ACCELERATION_USE_OPENCL, 1 });
+    cv::VideoWriter writer(OUTPUT_FILENAME, cv::CAP_FFMPEG, cv::VideoWriter::fourcc('V', 'P', '9', '0'), fps, cv::Size(WIDTH, HEIGHT), { cv::VIDEOWRITER_PROP_HW_ACCELERATION, cv::VIDEO_ACCELERATION_VAAPI, cv::VIDEOWRITER_PROP_HW_ACCELERATION_USE_OPENCL, 1 });
 
     if (!OFFSCREEN)
         x11::init();

src/optflow/optflow-demo.cpp

@@ -14,6 +14,7 @@
 constexpr unsigned long WIDTH = 1920;
 constexpr unsigned long HEIGHT = 1080;
 constexpr unsigned long DIAG = hypot(double(WIDTH), double(HEIGHT));
+constexpr const char* OUTPUT_FILENAME = "optflow-demo.mkv";
 constexpr bool OFFSCREEN = false;
 constexpr int VA_HW_DEVICE_INDEX = 0;
 
@@ -197,7 +198,7 @@ int main(int argc, char **argv) {
     }
 
     double fps = capture.get(cv::CAP_PROP_FPS);
-    cv::VideoWriter writer("optflow-demo.mkv", cv::CAP_FFMPEG, cv::VideoWriter::fourcc('V', 'P', '9', '0'), fps, cv::Size(WIDTH, HEIGHT), {
+    cv::VideoWriter writer(OUTPUT_FILENAME, cv::CAP_FFMPEG, cv::VideoWriter::fourcc('V', 'P', '9', '0'), fps, cv::Size(WIDTH, HEIGHT), {
             cv::VIDEOWRITER_PROP_HW_ACCELERATION, cv::VIDEO_ACCELERATION_VAAPI,
             cv::VIDEOWRITER_PROP_HW_ACCELERATION_USE_OPENCL, 1
     });