A PAL or NTSC video signal with no picture (black). The signal comprises line and field sync pulses as well as the color ‘burst’ before the start of each active TV line. It was widely used as an accurate timing reference for analog 626 and 525-line color equipment. You might have thought it has passed into history, but you would be wrong. Black and burst is still widely used as a sync reference timing signal for digital formats including SD, HD and UHD.