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Video Input and Output

Before you can digitize a moving image, you need to know what the analog form is, in terms of resolution and frame rate. Unfortunately, there are three main standards in use. PAL is used in the UK, while NTSC is used in the US and in JAPAN, and SECAM is used mainly in France and Russia. The differences are in number of lines, frame rate, scan order and so forth. PAL is used most widely - it uses 625 lines, and has a line rate of 50Hz. NTSC is used in the USA and Japan - it uses 525 lines, and a line rate of 59.94Hz. SECAM is used in France and Russia These all differ in number of lines, frame rate, interlace order and so on. There are also a number of variants of PAL and NTSC (e.g. I/PAL is used in the UK and Ireland, while M/NTSC is the ITU designation for the scheme used in the US and Japan).