576i

576i is a standard-definition digital video mode, originally used to make analog television digital in most countries where the utility frequency for power distribution is 50 Hz. Because of its association with older colour encoding systems, it is often referred to as PAL, PAL/SECAM or SECAM when compared to its 60 Hz NTSC colour-encoded counterpart, 480i.

576 identifies a vertical line count of 576 and the i identifies it as an interlaced resolution. The refresh rate, 50 Hz, is sometimes including when finding out the video mode, i.e. 576i50; another notation is the frame rate, endorsed by both the International telecommunications Union in BT.601 and SMPTE in SMPTE 259M to make it 576i/25.

576i Media

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  SDTV resolution by nation; countries using 576i are in blue.

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  Interlaced scanning: display of odd (green) and even (red) scanlines, and line return blanking periods (dotted)