PAL/NTSC/SECAM video decoder with adaptive PAL/NTSC comb ...

Philips Semiconductors
PAL/NTSC/SECAM video decoder with adaptive PAL/NTSC
comb filter, VBI-data slicer and high performance scaler
Preliminary specification
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
ndbook, full pagewidth
+235
white
+255
+240
blue 100%
+255
+240
+212 blue 75% +212
red 100%
red 75%
+128
LUMINANCE 100%
+128
colourless
+128
colourless
U-COMPONENT
V-COMPONENT
+16
0
black
+44
+16
0
yellow 75%
yellow 100%
+44
+16
0
cyan 75%
cyan 100%
MGC634
a. Y output range. b. U output range (C B ). c. V output range (C R ).
“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 I 2 C-bus bytes DBRI, DCON and DSAT.
Luminance:
Y OUT =
Int DCON
68
---------------- × ( Y – 128)
+ DBRI
Chrominance: UV OUT = Int DSAT --------------- × ( C
64 R , C B – 128)
+ 128
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