feat(libvideo2x): use OpenCV to retrieve total frame count (#1194)

.github/workflows/build.yml

@@ -30,7 +30,8 @@ jobs:
             libswscale-dev \
             libvulkan-dev \
             glslang-tools \
-            libomp-dev
+            libomp-dev \
+            libopencv-dev
       - name: Build Video2X
         run: |
           mkdir -p /tmp/build /tmp/install
@@ -63,6 +64,7 @@ jobs:
         run: |
           $ffmpegVersion = "7.1"
           $ncnnVersion = "20240820"
+          $opencvVersion = "4.10.0"
 
           git submodule update --init --recursive
 
@@ -73,9 +75,16 @@ jobs:
           curl -Lo ncnn-shared.zip "https://github.com/Tencent/ncnn/releases/download/$ncnnVersion/ncnn-$ncnnVersion-windows-vs2022-shared.zip"
           Expand-Archive -Path ncnn-shared.zip -DestinationPath third_party
           Rename-Item -Path "third_party/ncnn-$ncnnVersion-windows-vs2022-shared" -NewName ncnn-shared
+
+          curl -Lo opencv-shared.exe "https://github.com/opencv/opencv/releases/download/$opencvVersion/opencv-$opencvVersion-windows.exe"
+          7z x opencv-shared.exe -y
+          Move-Item -Path opencv -Destination third_party\opencv-shared
       - name: Build Video2X
+        shell: pwsh
         run: |
-          cmake -S . -B build -DUSE_SYSTEM_NCNN=OFF -DUSE_SYSTEM_SPDLOG=OFF -DCMAKE_BUILD_TYPE=Debug -DCMAKE_INSTALL_PREFIX=build/video2x_install
+          cmake -S . -B build `
+            -DUSE_SYSTEM_NCNN=OFF -DUSE_SYSTEM_SPDLOG=OFF -DUSE_SYSTEM_OPENCV=OFF `
+            -DCMAKE_BUILD_TYPE=Debug -DCMAKE_INSTALL_PREFIX=build/video2x_install
           cmake --build build --config Debug --parallel --target install
       - name: Upload artifacts
         uses: actions/upload-artifact@v4