Quantization The Video Signal - TAMUZ LSM 124W Operation Manual

Alignment of LCD Monitors
The AAC function has to adjusts hiddenly the systems setup of the monitor too, to compensate the
TFT panel qualities. Within lower color temperatures some colors are not reproducible regarding limi-
tations within the TFT panel itself.

Quantization the video signal

Please keep in mind; LCD panels have a 8 (6) bits wide date interface only.
All 10 bits of the original video signal must therefore be converted (Dithering) into a 8 bits word. Addi-
tionally the YUV range (16 to 235) has to stretched to fit within the RGB range (0 to 255). A Headroom
which consists in the YUV format is not there in RGB format.
So an original RGB signal looks more colorful, than a dithered YUV signal.
This color space conversions influences the linearity of the reproduction too. So a linear grey ramp
may looks stepped as below.
In general, there's a difference between the color space of computer graphic signals and SD or HD vi-
deo signals. Computer signals don't operate with head- or foot rooms, as video does.
© 02.07 TAMUZ - LCD Video Monitors
Note: Stepped grey ramps may be the result of the limited range of bits during color space
conversion and YUV signals. This is not a fault, it show the limitations of the system.
LSM Digital Broadcast Monitor
SPARROWHAWK
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