64-bit refers to sixty-four binary (0 or 1) units of integer data. This allows for up to 18,446,744,073,709,551,616 combinations of values.
- 64-bit color, is typically split into four sets of 16-bit values for 65,536 levels per RGBA channel (red, green, blue, and alpha). The three 16-bit RGB values deliver 281,474,976,710,656 unique colors, the same as 48-bit color, but with the addition of 65,536 levels of transparency defined by the alpha channel. This range is also known as "deep color". Apple ProRes 4444 stores video data in this color depth.
- 64-bit sound allows for a range of up to 18,446,744,073,709,551,616 values (−9,223,372,036,854,775,808 to +9,223,372,036,854,775,807) per sample (Hertz).
- 64-bit addressing allows for access to up to 18,446,744,073,709,551,616 bytes, or 18.4 exabytes of data.
- 64 bits of data make 8 bytes, referred to by programmers as a quadword.
- About Apple ProRes, Apple Inc. 2018-04-09.
- Mac OS X Tiger (10.4), the first version of Mac OS X to implement partial support for 64-bit applications.
- Mac OS X Snow Leopard (10.6), the first version to implement full 64-bit support, while maintaining backwards compatibility with 32-bit applications.
- macOS Catalina (10.15), the first version of macOS to operate solely in 64-bit, dropping support for 32-bit applications.
- PowerPC G5, the first 64-bit processor used by Apple Computer, in the Power Macintosh G5 computer.
- QuickTime X, the 64-bit successor to QuickTime.