ASTC Encoder

ASTC Encoder characteristics

The "astcenc" texture compressor is an open source compressor for the ASTC texture format. It is widely used due to its high image quality, and support for all of the color profiles and bit rates (block sizes) provided by the format.

Version 2.0 release significantly improves compression performance, with optimized paths for SSE4.2 and AVX2. It also provides an updated library API to allow direct integration of the codec into other applications.

Compressor Features

The compressor supports all of the format features, and provides a highly configurable codec with command line access to all of the compressor heuristics.

• All 2D block sizes, allowing control of bit rate from 0.89 bits/pixel up to 8 bits/pixel in fine steps.
• All 3D block sizes, allowing control of bit rate from 0.59 bits/pixel up to 4.74 bites/pixel in fine steps.
• All color profile, allowing linear LDR, sRGB LDR, and HDR images.
• Support for dedicated perceptual compression modes for normal maps and mask textures.

For image compression the following formats are supported:

• Loading LDR images in BMP, JPEG, PNG, and TGA formats.
• Loading HDR images in OpenEXR and Radiance HDR formats.
• Loading uncompressed LDR and HDR images stored in the DDS or KTX container formats.
• Storing compressed textures into the “.astc” file format provided by astcenc, or the KTX container format.

For image decompression the following formats are supported:

• Loading compressed textures in the “.astc” file format provided by astcenc, and the KTX container format.
• Storing LDR images into BMP, PNG, and TGA formats.
• Storing HDR images into OpenEXR and Radiance HDR formats.
• For image analysis the tool supports a test mode which provides image quality statistics about the compressed image.