Video Levels

The video levels define the levels and ranges for the different parts of the video signal. The unit used to define video levels is the IRE (Institute of Radio Engineers). The blanking level refers to 0 IRE and the white level refers to +100 IRE. The blanking level, which is the reference level for the video signal (usually 0 V), is different from the black level if a setup is applied to the signal as shown in the following figure:


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For the M-NTSC, M-PAL and N-PAL video formats, a setup of 7.5 IRE is usually applied, moving the black level to +7.5 IRE. For all other formats, the black level is aligned with the blanking level at 0 IRE.

The following table shows the different video levels depending on the video format:
Video Format Sync Level Blanking Level Black Level White Level Peak Level Burst Amplitude
M-NTSC –40 IRE 0 IRE +7.5 IRE +100 IRE +120 IRE 20.0 IRE
B/G-PAL –43 IRE 0 IRE 0 IRE +100 IRE +133 IRE 21.5 IRE
SECAM –43 IRE 0 IRE 0 IRE +100 IRE +130 IRE N/A
M-PAL –40 IRE 0 IRE +7.5 IRE +100 IRE +120 IRE 20.0 IRE
N-PAL –40 IRE 0 IRE +7.5 IRE +100 IRE +133 IRE 20.0 IRE
Comb. N-PAL –43 IRE 0 IRE 0 IRE +100 IRE +133 IRE 21.5 IRE

The analog composite video signal is defined as a voltage source with an output impedance of 75 Ω. The sync-to-white level is normally 1 Vpk-pk when loaded with a 75 Ω resistance. Therefore, the unloaded signal is nominally 2 Vpk-pk.

For NTSC, the difference between white and sync levels is 140 IRE, so the analog level corresponds to approximately 7.143 mV/IRE. For B/G-PAL or SECAM, the difference between white and sync levels is 143 IRE, so the analog level corresponds to approximately 7.000 mV/IRE.