Update the video conversion: Ensure the correct file order

tests/ANSCV-UnitTest/ANSCV-UnitTest.cpp

@@ -13,6 +13,9 @@
 #include <fstream>
 #include <iostream>
 #include <string>
+#include <chrono>
+#include <algorithm>
+#include <cctype>
 
 using namespace ANSCENTER;
 using namespace cv;
@@ -1369,7 +1372,62 @@ int TestGetImage() {
 int GenerateVideo() {
    std::string imageFolder = "E:\\Programs\\DemoAssets\\ImageSeries\\20260415_142435.655";
    std::string outputVideoPath = "E:\\Programs\\DemoAssets\\ImageSeries\\output7.mp4";
-   int conversionResult = ANSCV_ImagesToMP4_S(imageFolder.c_str(), outputVideoPath.c_str(), 0,20);
+
+   // Enumerate + sort by filename (same comparator the DLL uses) so we can
+   // preview the exact playback order.
+   std::vector<std::string> images;
+   try {
+      for (const auto& entry : std::filesystem::directory_iterator(imageFolder)) {
+         if (!entry.is_regular_file()) continue;
+         std::string ext = entry.path().extension().string();
+         std::transform(ext.begin(), ext.end(), ext.begin(),
+                        [](unsigned char c) { return std::tolower(c); });
+         if (ext == ".jpg" || ext == ".jpeg" || ext == ".png" ||
+             ext == ".bmp" || ext == ".tif" || ext == ".tiff") {
+            images.push_back(entry.path().string());
+         }
+      }
+   } catch (const std::exception& e) {
+      std::cerr << "Warning: could not enumerate image folder: " << e.what() << std::endl;
+   }
+   std::sort(images.begin(), images.end(),
+             [](const std::string& a, const std::string& b) {
+                return std::filesystem::path(a).filename().string() <
+                       std::filesystem::path(b).filename().string();
+             });
+   size_t imageCount = images.size();
+
+   std::cout << "[Benchmark] ImagesToMP4_S" << std::endl;
+   std::cout << "  source folder : " << imageFolder << std::endl;
+   std::cout << "  output file   : " << outputVideoPath << std::endl;
+   std::cout << "  image count   : " << imageCount << std::endl;
+   std::cout << "  fps argument  : 20" << std::endl;
+
+   // Print the on-disk playback order (what the DLL will consume).
+   std::cout << "  playback order:" << std::endl;
+   for (size_t i = 0; i < images.size(); ++i) {
+      std::cout << "    [" << (i + 1) << "] "
+                << std::filesystem::path(images[i]).filename().string() << std::endl;
+   }
+
+   auto t0 = std::chrono::high_resolution_clock::now();
+   int conversionResult = ANSCV_ImagesToMP4_S(imageFolder.c_str(), outputVideoPath.c_str(), 0, 20);
+   auto t1 = std::chrono::high_resolution_clock::now();
+
+   auto elapsed_us = std::chrono::duration_cast<std::chrono::microseconds>(t1 - t0).count();
+   double elapsed_ms = elapsed_us / 1000.0;
+   double elapsed_s  = elapsed_us / 1000000.0;
+
+   std::cout << "[Benchmark] ImagesToMP4_S finished." << std::endl;
+   std::cout << "  result        : " << conversionResult << std::endl;
+   std::cout << "  elapsed       : " << elapsed_ms << " ms  (" << elapsed_s << " s)" << std::endl;
+   if (imageCount > 0) {
+      double per_image_ms = elapsed_ms / static_cast<double>(imageCount);
+      double throughput   = static_cast<double>(imageCount) / elapsed_s;
+      std::cout << "  per image     : " << per_image_ms << " ms" << std::endl;
+      std::cout << "  throughput    : " << throughput << " images/s" << std::endl;
+   }
+
    if (!conversionResult) {
        std::cerr << "Failed to convert images to MP4." << std::endl;
       return -1;