3D LUT color grading and toning on NVIDIA GPU
3D LUT Transform is massively used for color grading and toning applications. To solve the task of 3D LUT grading, we have developed high performance CUDA kernels that run on existing GPU hardware from NVIDIA. We have implemented various formats for 3D LUTs and achieved very high performance for color grading.
To utilize 3D LUT for color grading and toning, we've implemented integration of Fast CinemaDNG Processor with 3DLUT Creator software. User can choose any frame from raw sequence and send processed 16-bit TIFF to 3DLUT Creator. That software can prepare 3D LUT which will be sent back to Fast CinemaDNG Processor for realtime color grading on GPU.
3DLUT grading features
- Input data 16-bit per color channel with arbitrary width and height
- 2.5D and 3D LUT formats: cube
- Color representation: RGB, HSV
- Color cube resolution up to 65×65×65 (optionally up to 256×256×256)
Hardware and software
- CPU Intel Core i7-5930K (Haswell-E, 6 cores, 3.5–3.7 GHz)
- GPU NVIDIA GeForce GTX 1080 (Pascal, 20 SMM, 2560 cores, 1.6–1.7 GHz)
- OS Windows 7/8/10 SP1 (x64)
- CUDA Toolkit 9.2
Performance of 2.5D (HSV) and 3D LUT (RGB) Transforms on GPU
Test images: 16-bit RGB, 2432×1366 (2.5K) and 4032×2192 (4K), fast trilinear interpolation
Test info: all data (input and output) in GPU memory, timing measurements include GPU computations only, timings for 2.5K/4K images
- 2.5D LUT (HSV, 90×30 points) – 0.26 ms / 0.64 ms
- 2.5D LUT (HSV, 90×117 points) – 0.26 ms / 0.65 ms
- 3D LUT (HSV, 36×8×8 points) – 0.29 ms / 0.65 ms
- 3D LUT (HSV, 36×29×16 points) – 0.31 ms / 0.68 ms
- 3D LUT (HSV, 36×57×61 points) – 0.44 ms / 0.77 ms
- 3D LUT (RGB, 17×17×17) – 0.22 ms / 0.55 ms
- 3D LUT (RGB, 33×33×33) – 0.22 ms / 0.56 ms
- 3D LUT (RGB, 65×65×65) – 0.30 ms / 0.60 ms
Maximum 3D LUT (RGB) size could reach 256×256×256.
In that case processing time for 16-bit 4K image with such 3D LUT on GeForce GTX 1080 is in the range of 4-8 ms.