ASTC Evaluation Codec on Github

The ASTC Evaluation Codec is a command-line executable that compresses and decompresses images using the Adaptive Scalable Texture Compression standard. Running on a standard PC, this tool allows content developers to evaluate the impressive quality and size benefits offered by this texture compression format, in advance of it being available in GPU hardware.

ASTC Evaluation Codec repository (Github)

Why is this now on GitHub?

We wanted to use GitHub to bring ASTC to the heart of the developer open-source community.

With the source code available on GitHub, it is even easier for every developer to access, clone, browse and contribute feedback and improvements. Since ASTC is a standard, the whole community benefits from it, and there is now a straightforward way to share fixes and new features.

For technical details on ASTC, please refer to the blog posts by Tom Olson and Sean Ellis.

ASTC Evaluation Codec characteristics


  • Compression of PNG, TGA and KTX into ASTC format
  • Control of bit rate from 0.89 bits/pixel upto 8bits/pixel in fine steps
  • Control of compression time/quality tradeoff with exhaustive, thorough, medium, fast and very fast encoding speeds
  • Supports both low (LDR) and high dynamic range (HDR) images
  • Supports 3D texture compression
  • Measure PSNR between input and output


  • Decodes ASTC images to TGA or KTX.