Many emulators offer a CRT filter, an artist's rendition of classic video. This presentation describes emulation of the an entire NTSC or PAL video device, to produce an engineer's rendition — starting from sync discrimination and separation, through PLLs into scan placement and via QAM to extracting colour. In the implementation discussed work is split between CPU and GPU and a range of emulated source machines are demonstrated, including in-phase machines such as the Atari 2600, machines that routinely generate sync errors such as the ZX80, machines that generate a colour signal in software such as the Apple II, and interlaced machines such as the Acorn Electron.