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By applying the information from the previous section, you can make some comparisons of different formats. For analog formats, information relevant to the visual resolution will be listed. For digital formats the display resolution will be given. Remember, when watching digital video on an analog television you need to consider the number of TV Lines it can reproduce the hard limit on visual resolution. The numbers listed for minimum capture resolution are based on the Nyquist frequency. The actual resolution you should capture at depends on your hardware.

Digital to Analog Calculations


Maximum visual resolution for a given analog signal can be calculated based on its frequency compared to the amount of time each active line takes to draw on the screen. This is also known as the active period. For NTSC the active period is 52.6555s (52 microseconds or .0000526555 seconds). For PAL it's 52s. The ITU recommendation assumes a frequency of 53.333s which is longer than either one. This means that not all of the 720 pixels in the ITU standard will be used for a picture. PAL, with an active period of 52s uses the center 702 pixels (97.5% of 720). NTSC, with an active period of 52.6555s uses 710 pixels (98.7% of 720). As a general rule, this calculation should be valid for digital sources designed to work with both PAL and NTSC video. Those designed specifically for one or the other, like DV, will generally have an active area that exactly matches either PAL or NTSC, meaning all pixels can be displayed in the active period of your television.

Broadcast PAL


Frequency: 5MHz
Max. TV Lines: 520
Scan Lines: 576

Broadcast NTSC


Frequency: 4.2MHz
Max. TV Lines: 442
Scan Lines: 483

VHS


Frequency: 3MHz
Max. PAL TV Lines: 312
Max. NTSC TV Lines: 316

S-VHS


Frequency: 5MHz
Max. PAL TV Lines: 520
Max. NTSC TV Lines: 526

VCD or DVD (SIF)


PAL Resolution: 352x288
NTSC Resolution: 352x240
Active Period: 52.148s
Max. PAL TV Lines: 350
Max. NTSC TV Lines: 352

DVD


PAL Resolution: 352x576
NTSC Resolution: 352x480
Active Period: 52.148s
Max. PAL TV Lines: 350
Max. NTSC TV Lines: 352

SVCD


PAL Resolution: 480x576
NTSC Resolution: 480x480
Active Period: 53.333s
Max. PAL TV Lines: 468
Max. NTSC TV Lines: 474

DVD (Broadcast D1)


PAL Resolution: 704x576
NTSC Resolution: 704x480
Active Period: 52.148s
Max. PAL TV Lines: 702
Max. NTSC TV Lines: 704

DVD (Full D1) or DV


PAL Resolution: 720x576
NTSC Resolution: 720x480
Active Period: 53.333s
Max. PAL TV Lines: 702
Max. NTSC TV Lines: 710
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Table of Contents

  1. 1. Introduction
  2. 2. Definitions
  3. 3. Resolution of Common Formats
  4. 4. Aspect Ratio
Written by: Rich Fiscus