A Note from Hyeon-ki Lee

The H-ETC2 code provided here is a modified version of etcpak 1.0, based on the following article: Hyeon-ki Lee and Jae-ho Nah, “H-ETC2 : Design of a CPU-GPU Hybird ETC2 Encoder,” Computer Graphics Forum (Proc. of Pacific Graphics 2023). https://diglib.eg.org/handle/10.1111/cgf14969

This encoder is built upon etcpak and Betsy. The CPU and GPU encoding parts focus on encoding speed and quality, respectively. By setting proper modes in the argument list as described in the below section, an input image can be compressed with our CPU/GPU hybrid encoding mode.

Get started (Windows only)

First, we have to build Betsy and etcpak.

etcpak
BetsyGPU
Our project

Second, copy SDL2.dll in a betsyGPU project build folder to our project build folder because our project requires SDL2.dll.

C:\YOUR_HETC2_PROJECT_PATH\build\x64> dir 
    ..
    etcpak.exe
    SDL2.dll

Third, if you want to execute the encoder, you need to input the below command line.

C:\YOUR_HETC2_PROJECT_PATH\build\x64> etcpak --betsy-mode -M --[MODE] [INPUT].png [OUTPUT].ktx

Example

C:\YOUR_HETC2_PROJECT_PATH\build\x64> etcpak --betsy-mode -M --best example.png example.ktx

If you want to uncompress a file, please input below; it is the same as the usage of the original etcpak.

C:\YOUR_HETC2_PROJECT_PATH\build\x64> etcpak -v example.ktx example.png

etcpak 1.0

(Updated 2022-06-04) start dev

The fastest ETC compressor on the planet

etcpak is an extremely fast Ericsson Texture Compression and S3 Texture Compression (DXT1/DXT5) utility. Currently it's best suited for rapid assets preparation during development, when graphics quality is not a concern, but it's also used in production builds of applications used by millions of people.

Compression times

Benchmark performed on an AMD Ryzen 9 5950X, using a real-life RGBA 16K × 16K atlas.

ETC1: ST: 407 Mpx/s, MT: 6730 Mpx/s
ETC2: ST: 222 Mpx/s, MT: 3338 Mpx/s
DXT1: ST: 2688 Mpx/s, MT: 8748 Mpx/s
DXT5: ST: 1281 Mpx/s, MT: 6667 Mpx/s

The same benchmark performed on Intel i7 1185G7:

ETC1: ST: 463 Mpx/s, MT: 2189 Mpx/s
ETC2: ST: 229 Mpx/s, MT: 1003 Mpx/s
DXT1: ST: 2647 Mpx/s, MT: 9173 Mpx/s
DXT5: ST: 1294 Mpx/s, MT: 5517 Mpx/s

ARM benchmark performed on Odroid C2, using the same atlas:

ETC1: ST: 23.6 Mpx/s, MT: 90.6 Mpx/s
ETC2: ST: 12.3 Mpx/s, MT: 48.4 Mpx/s
DXT1: ST: 93.2 Mpx/s, MT: 346 Mpx/s
DXT5: ST: 68.5 Mpx/s, MT: 256 Mpx/s

Why there's no image quality metrics? / Quality comparison.