GCV

OpenGL/OpenCL/VAAPI interop demos (aka. run it on the GPU!) using my 4.x fork of OpenCV (https://github.com/kallaballa/opencv/tree/GCV)

The goal of the demos is to show how to use OpenCL interop in conjunction with OpenCV 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.

• The author of the example video (which is also used for two of the demo videos in this README) is (c) copyright Blender Foundation | www.bigbuckbunny.org.
• The right holders of the video used for the optical flow visualization are https://www.bbtv.com. I tried to contact them several times to get an opinion on my fair-use for educational purpose. The original video: https://www.youtube.com/watch?v=ItGwXRCcisA

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

There are currently six demos (the preview videos are scaled down and compressed):

tetra-demo

Renders a rainbow tetrahedron on blue background using OpenGL and decodes/encodes on the GPU.

https://user-images.githubusercontent.com/287266/200169105-2bb88288-cb07-49bb-97ef-57ac61a0cfb8.mp4

video-demo

Renders a rainbow tetrahedron on top of a input-video using OpenGL and decodes/encodes on the GPU.

https://user-images.githubusercontent.com/287266/200169164-231cb4d8-db5c-444b-8aff-55c9f1a822cc.mp4

nanovg-demo

Renders a color wheel on top of a input-video using nanovg (OpenGL) and decodes/encodes on the GPU.

https://user-images.githubusercontent.com/287266/200169216-1ff25db5-f5e0-49d1-92ba-ab7903168754.mp4

font-demo

Renders a Star Wars like text crawl using nanovg (OpenGL). Encodes on the GPU.

https://user-images.githubusercontent.com/287266/204157553-758adaeb-e9b8-48eb-bc09-8098a5379d2b.mp4

optflow-demo

My take on a optical flow visualization on top of a video. Uses nanovg for rendering (OpenGL), calculates the optical flow (OpenCL) and decodes/encodes on the GPU.

https://user-images.githubusercontent.com/287266/202174513-331e6f08-8397-4521-969b-24cbc43d27fc.mp4

pedestrian-demo

Pedestrian detection using HOG/SVM and non-maximal suppression. Uses nanovg for rendering (OpenGL), detects using a SVM (OpenCL) and decodes/encodes on the GPU. Note: Detection rate is not impressive and depends highly on the video.

https://user-images.githubusercontent.com/287266/204364376-e08a4943-17a4-408f-a5b0-bfd95ffc44ae.mp4

Instructions

You need to build the most recent 4.x branch of OpenCV.

Build OpenCV

git clone --branch GCV https://github.com/kallaballa/opencv.git
cd opencv
mkdir build
cd build
ccmake -DCMAKE_BUILD_TYPE=Release -DOPENCV_ENABLE_GLX=OFF -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 ..
make -j8
sudo make install

Build demo code

git clone https://github.com/kallaballa/GCV.git
cd GCV
make

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

Run the tetra-demo:

src/tetra/tetra-demo

Run the video-demo:

src/video/video-demo bunny.webm

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