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What's new in 3.4? · Decode some bitstreams · Coding performance

Cool-chic (pronounced /kul ʃik/ as in French 🥖🧀🍷) is a low-complexity neural image codec based on overfitting. It offers image coding performance competitive with H.266/VVC for 1000 multiplications per decoded pixel.

#### 🏆 **Coding performance**: Cool-chic compresses images as well as H.266/VVC 🏆 #### 🚀 **Fast CPU-only decoder**: Decode a 1280x720 image in 100 ms on CPU with our decoder written in C 🚀 #### 🔥 **Fixed-point decoder**: Fixed-point arithmetic at the decoder for bit-exact results on different hardwares 🔥 #### 🖼️ **I/O format**: Encode PNG, PPM and YUV 420 & 444 files with a bitdepth of 8 to 16 bits 🖼️

### Latest release: 🎉 __Cool-chic 3.4: 30% less complex!__ 🎉

New and improved latent upsampling module
- Leverage symmetric and separable convolution kernels to reduce complexity & parameters count
- Learn two filters per upsampling step instead of one for all upsampling steps
1% to 5% rate reduction for the same image quality
30% complexity reduction using a smaller Auto-Regressive Module
- From 2000 MAC / decoded pixel to 1300 MAC / decoded pixel
- 10% faster decoding speed

Check-out the release history to see previous versions of Cool-chic.

Setup

More details are available on the Cool-chic page

# We need to get these packages to compile the C API and bind it to python.
sudo add-apt-repository -y ppa:deadsnakes/ppa && sudo apt update
sudo apt install -y build-essential python3.10-dev pip
git clone https://github.com/Orange-OpenSource/Cool-Chic.git && cd Cool-Chic

# Install create and activate virtual env
python3.10 -m pip install virtualenv
python3.10 -m virtualenv venv && source venv/bin/activate

# Install Cool-chic
pip install -e .

# Sanity check
python -m test.sanity_check

You're good to go!

Performance

The Cool-chic page provides comprehensive rate-distortion results and compressed bitstreams allowing to reproduce the results inside the results/ directory.

	BD-rate of Cool-chic 3.4 vs. [%]						Avg. decoder complexity
	Cheng	ELIC	Cool-chic 3.3	C3	HEVC (HM 16)	VVC (VTM 19)	MAC / pixel	CPU Time [ms]
kodak	-4.2 %	+7.5 %	-0.9 %	-4.3 %	-17.2 %	+3.4 %	1303	74
clic20-pro-valid	-13.2 %	-0.2 %	-0.3 %	-1.3 %	-25.1 %	-2.3 %	1357	354
jvet	/	/	-0.2 %	/	-18.3 %	+18.6 %	1249	143

Decoding time are obtained on a single CPU core of an an AMD EPYC 7282 16-Core Processor

PSNR is computed in the RGB domain for kodak and CLIC20, in the YUV420 domain for jvet

Kodak

CLIC20 Pro Valid

JVET Class B

Thanks

Special thanks go to Hyunjik Kim, Matthias Bauer, Lucas Theis, Jonathan Richard Schwarz and Emilien Dupont for their great work enhancing Cool-chic: C3: High-performance and low-complexity neural compression from a single image or video, Kim et al.

Orange-OpenSource / Cool-Chic