ASTC offers a number of advantages over existing texture compression schemes:
- Flexibility, with bit rates from 8 bits per pixel (bpp) down to less than 1 bpp. This allows content developers to fine-tune the tradeoff between quality versus texture size and upload bandwidth.
- Support for 1 to 4 color channels, with modes for uncorrelated channels for use in mask textures and normal maps.
- Support for both low dynamic range (LDR) and high dynamic range (HDR) images.
- Support for both 2D and 3D images.
- Interoperability: Developers can choose any combination of features that suits their needs.
ASTC specification includes two profiles: LDR and Full. Both of these are supported on the latest Mali GPUs, including the Mali™-T620, Mali-T720, Mali-T760, Mali-T820/T830 and Mali-T860/T880. The smaller LDR Profile supports 2D low dynamic range images only. It is designed to be easy to integrate with existing hardware designs that already deal with compressed 2D images in other formats. The LDR Profile is a strict subset of the Full Profile, which also includes the 3D textures and high dynamic range support.
GDC Booth Presentation by ARM - ASTC: the future of texture compression. Tom Olson, Director of Graphics Research at ARM explains why texture compression is important before moving onto the feature set and image quality of ASTC.