Philips Semiconductors
Product specification
Multimedia bridge, high performance
Scaler and PCI circuit (SPCI)
SAA7146A
Table 59 αRGB-32 format
PACKING WITHIN 32-BIT Dword
BIT 23 TO BIT 16 BIT 15 TO BIT 8
BIT 31 TO BIT 24
BIT 7 TO BIT 0
α/−
α/−
R
G
B
U
V
Y
Table 60 RGB-24 packed format
PACKING WITHIN 32-BIT Dword
BUS CYCLE
BIT 31 TO BIT 24
BIT 23 TO BIT 16
BIT 15 TO BIT 8
BIT 7 TO BIT 0
1
2
3
B1
G2
R3
R0
B2
G3
G0
R1
B3
B0
G1
R2
The following formats use two pixels per Dword and derive
RGB from RGB-24 by truncation or by error diffusion
dither. The byte phase of the first sample each line is
defined by LSB + 1 of DMA base. ‘α’ is the colour key.
7.11.1.2 YUV
All YUV formats are based on CCIR coding:
Luminance Y in straight binary:
Black: Y = 16 of 256 linear coding
White: Y = 235 of 256 linear coding.
• RGB-16 (5 : 6 : 5): Red has 5 bits, Green has 6 bits,
Blue has 5 bits
• RGB-15 (α : 5 : 5 : 5): α-bit, Red has 5 bits, Green has
5 bits, Blue has 5 bits
Colour difference signals UV in offset binary:
No colour: U = V = 128 of 256 steps
Full colour: U = V = 128 ±112 steps.
• RGB-15 (5 : 5 : α : 5): Red has 5 bits, Green has 5 bits,
α bit, Blue has 5 bits.
• YUV 4 : 2 : 2: U and V sampled co-sided with first
Y sample (of 2 samples in-line). Byte phase of the first
sample each line is defined by bit 0 and bit 1 of DMA
base address (see Table 62).
Table 61 RGB-16 formats Dword
PACKING WITHIN 32-BIT Dword
BIT 31 TO BIT 16
BIT 15 TO BIT 0
• YUV 4 : 1 : 1: U and V sampled co-sided with first
Y sample, (of 4 samples in-line), 8 samples are packed
in 3 Dwords (see Table 63).
Pixel1
Pixel0
1998 Apr 09
81
NXP [ NXP ]
