Philips Semiconductors
Preliminary specification
PAL/NTSC/SECAM video decoder with adaptive PAL/NTSC
comb filter, VBI-data slicer and high performance scaler
SAA7114H
8.1.3.3
Brightness Contrast Saturation (BCS) control and decoder output levels
The resulting Y (CVBS) and UV-signals are fed to the BCS block, which contains the following functions:
• Chrominance saturation control by DSAT7 to DSAT0
• Luminance contrast and brightness control by DCON7 to DCON0 and DBRI7 to DBRI0
• Raw data (CVBS) gain and offset adjustment by RAWG7 to RAWG0 and RAWO7 to RAWO0
• Limiting YUV or CVBS to the values 1 (minimum) and 254 (maximum) to fulfil “ITU Recommendation 601/656”.
+255
+255
+240
+255
+240
ndbook, full pagewidth
blue 100%
blue 75%
red 100%
red 75%
white
+235
+212
+212
colourless
colourless
LUMINANCE 100%
+128
+128
+128
U-COMPONENT
V-COMPONENT
yellow 75%
cyan 75%
+44
+16
0
+44
+16
0
yellow 100%
cyan 100%
black
+16
0
MGC634
a. Y output range.
b. U output range (CB).
c. V output range (CR).
“ITU Recommendation 601/656” digital levels with default BCS (decoder) settings DCON[7:0] = 44H, DBRI[7:0] = 80H and DSAT[7:0] = 40H.
Equations for modification to the YUV levels via BCS control I2C-bus bytes DBRI, DCON and DSAT.
DCON
68
Luminance:
YOUT = Int
× (Y – 128) + DBRI
-----------------
DSAT
---------------
64
Chrominance: UVOUT = Int
× (C , C B – 128) + 128
R
It should be noted that the resulting levels are limited to 1 to 254 in accordance with “ITU Recommendation 601/656” .
Fig.17 YUV range for scaler input and X-port output.
2000 Mar 15
28
NXP [ NXP ]
