Viz2D

Viz2D is a 2D visualization library based on OpenCV. It features OpenCL/ OpenGL, OpenCL/VAAPI interoperability and a GUI based on nanogui. It should be included in OpenCV-contrib once it is ready.

Attribution

• The author of the bunny video is (c) copyright Blender Foundation | www.bigbuckbunny.org.
• The author of the dance video is GNI Dance Company (Original video)
• The author of the video used in the beauty-demo video is Kristen Leanne (Original video)

Demos

The goal of the demos is to show how to use Viz2D in conjunction with interop options on Linux to create programs that run mostly (the part the matters) on the GPU. Until the necessary changes are pulled into the official repository you need to build my fork of OpenCV 4.x.

There are currently eight demos. The shader-demo, font-demo, optflow-demo and beauty-demo can be compiled to WebAssembly using Emscripten but for now you have to figure out how to do it yourself :).

Online Demos

Please note that the following online demos are slower and/or have less features than the native versions.

• https://viel-zu.org/opencv/shader
• https://viel-zu.org/opencv/font
• https://viel-zu.org/opencv/optflow
• https://viel-zu.org/opencv/beauty

Requirements

• Support for OpenCL 1.2
• Support for cl_khr_gl_sharing and cl_intel_va_api_media_sharing OpenCL extensions.
• If you are on a recent Intel Platform (Gen8 - Gen12) you need to install an alternative compute-runtime

Dependencies

• EGL
• GLEW
• GLFW3
• nanovg
• nanogui

tetra-demo

Renders a rainbow tetrahedron on blue background using OpenGL, applies a glow effect using OpenCV (OpenCL) and encodes on the GPU (VAAPI).

https://user-images.githubusercontent.com/287266/222984424-e0914bd4-72f3-4777-8a61-28dee6dd3573.mp4

video-demo

Renders a rainbow tetrahedron on top of a input-video using OpenGL, applies a glow effect using OpenCV (OpenCL) and decodes/encodes on the GPU (VAAPI).

https://user-images.githubusercontent.com/287266/222984530-c8c39997-ed3c-4675-92c9-40e4a7ea306a.mp4

shader-demo

Renders a mandelbrot fractal zoom. Uses shaders, OpenCL and VAAPI together.

https://user-images.githubusercontent.com/287266/222971445-13b75aee-f190-419d-9772-404d32ff61f2.mp4

nanovg-demo

Renders a color wheel on top of an input-video using nanovg (OpenGL), does colorspace conversions using OpenCV (OpenCL) and decodes/encodes on the GPU (VAAPI).

https://user-images.githubusercontent.com/287266/222984631-a7e3522a-8713-4413-ab5e-e6b55cd52ce8.mp4

font-demo

Renders a Star Wars like text crawl using nanovg (OpenGL), uses OpenCV (OpenCL) for a pseudo 3D effect and encodes on the GPU (VAAPI).

https://user-images.githubusercontent.com/287266/222984217-50af8dc1-72cb-4998-babe-53a2114745cf.mp4

optflow-demo

My take on a optical flow visualization on top of a video. Uses background subtraction (OpenCV/OpenCL) to isolate areas with motion, detects features to track (OpenCV/OpenCL), calculates the optical flow (OpenCV/OpenCL), uses nanovg for rendering (OpenGL) and post-processes the video (OpenCL). Decodes/encodes on the GPU (VAAPI).

https://user-images.githubusercontent.com/287266/222980868-e032bc80-0a2a-4406-b64e-7b2acdc22416.mp4

pedestrian-demo

Pedestrian detection using HOG with a linear SVM, non-maximal suppression and tracking using KCF. Uses nanovg for rendering (OpenGL), detects using a linear SVM (OpenCV/OpenCL), filters resuls using NMS (CPU) and tracks using KCF (CPU). Decodes/encodes on the GPU (VAAPI).

https://user-images.githubusercontent.com/287266/222980241-d631f7e5-e7a3-446e-937e-bce34e194bd1.mp4

beauty-demo

Face beautification using face landmark detection (OpenCV/OpenCL), nanovg (OpenGL) for drawing masks and multi-band blending (CPU) to put it all together.

https://user-images.githubusercontent.com/287266/222982914-ff5be485-4aec-4d6b-9eef-378f6b10d773.mp4

Instructions

You need to build my 4.x branch of OpenCV, OpenCV-contrib, nanovg and nanogui.

Install build dependencies

apt install vainfo clinfo libqt5opengl5-dev freeglut3-dev ocl-icd-opencl-dev libavcodec-dev libavdevice-dev libavfilter-dev libavformat-dev libavutil-dev libpostproc-dev libswresample-dev libswscale-dev libglfw3-dev libstb-dev libglew-dev cmake make git-core build-essential opencl-clhpp-headers pkg-config zlib1g-dev doxygen

Build nanovg

git clone https://github.com/inniyah/nanovg.git
mkdir nanovg/build
cd nanovg/build
cmake -DCMAKE_BUILD_TYPE=Release ..
make -j8
sudo make install

Build nanogui

git clone --recursive https://github.com/mitsuba-renderer/nanogui.git
mkdir nanogui/build
cd nanogui/build
cmake -DCMAKE_BUILD_TYPE=Release -DNANOGUI_BACKEND=OpenGL -DNANOGUI_BUILD_EXAMPLES=OFF -DNANOGUI_BUILD_GLFW=OFF -DNANOGUI_BUILD_PYTHON=OFF ..
make -j8
sudo make install

Build OpenCV-fork with OpenCV-contrib

git clone --branch 4.x https://github.com/opencv/opencv_contrib.git
git clone --branch GCV https://github.com/kallaballa/opencv.git
mkdir opencv/build
cd opencv/build
cmake -DCMAKE_BUILD_TYPE=Release -DOPENCV_ENABLE_GLX=ON -DOPENCV_ENABLE_EGL=ON -DOPENCV_FFMPEG_ENABLE_LIBAVDEVICE=ON -DWITH_OPENGL=ON -DWITH_QT=ON -DWITH_FFMPEG=ON -DOPENCV_FFMPEG_SKIP_BUILD_CHECK=ON -DWITH_VA=ON -DWITH_VA_INTEL=ON -DBUILD_PERF_TESTS=OFF -DBUILD_TESTS=OFF -DBUILD_EXAMPLES=OFF -DOPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules/ -D BUILD_opencv_aruco=OFF ..
make -j8
sudo make install

Build demo code

git clone https://github.com/kallaballa/Viz2D.git
cd Viz2D
make -j8

Download the example file

wget -O bunny.webm https://upload.wikimedia.org/wikipedia/commons/transcoded/f/f3/Big_Buck_Bunny_first_23_seconds_1080p.ogv/Big_Buck_Bunny_first_23_seconds_1080p.ogv.1080p.vp9.webm

Point to libviz2d.so

Before you can run the demos you have to point to libviz2d.so

cd Viz2D
export LD_LIBRARY_PATH=src/common:$LD_LIBRARY_PATH

Run the tetra-demo:

src/tetra/tetra-demo

Run the video-demo:

src/video/video-demo bunny.webm

Run the shader-demo:

src/shader/shader-demo

Run the nanovg-demo:

src/nanovg/nanovg-demo bunny.webm

Run the font-demo:

src/font/font-demo

Run the optflow-demo:

src/optflow/optflow-demo bunny.webm

Run the pedestrian-demo:

src/pedestrian/pedestrian-demo bunny.webm

Run the beauty-demo:

src/beauty/beauty-demo bunny.webm