A four-component, 64-bit packed unsigned normalized format that has a 10-bit A component in bits 30..39, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9. The components are gamma encoded and their values range from -0.5271 to 1.66894. The alpha component is clamped to either 0.0 or 1.0 on sampling, rendering, and writing operations.