A horizontal line (a row) in a video frame. Camcorders sense image frames a line at a time, and display systems create images a line at a time. The scan lines are the vertical resolution of the system; for example, an NTSC TV signal uses 525 lines, 480 of which contain image data ("active" scan lines) and 45 are the vertical blanking interval (VBI) in between the frames. Following are the active scan lines of various video formats. See scan rate and horizontal scan frequency.
Analog Active
Formats Scan Lines
VHS 240
8mm 240
Sony U-matic 3/4" 250
Sony U-matic SP 330
S-VHS 400
Hi8 400
Laserdisc 425
NTSC 480 out of 525 total
PAL/SECAM 580 out of 625 total
Digital Active
Formats Scan Lines
DVD 480
DV 480
SDTV Digital TV 480
EDTV Digital TV 480
HDTV Digital TV 720 & 1080
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