Philips Semiconductors
Preliminary specification
PAL/NTSC/SECAM video decoder with adaptive PAL/NTSC
comb filter, VBI-data slicer and high performance scaler
SAA7114H
scaled output,
no phase offset
scaled output,
with phase offset
handbook, full pagewidth
field 1
unscaled input
field 2
field 1
field 2
field 1
field 2
correct scale dependent position
scale dependent start offset
mismatched vertical line distances
MHB547
Fig.28 Basic problem of interlaced vertical scaling (example: down-scale 3⁄5).
handbook, full pagewidth
field 1
upper
field 2
lower
field 1
field 2
field 1
field 2
case UP-UP
case LO-LO
case UP-LO
case LO-UP
B
A
C
D
MHB548
1024
32
1
2
1
2
YSCY[15:0]
Offset =
= 32 = 1 line shift
------------
B = -- input line shift+ -- scale increment =
+ 16
------------------------------
64
1
2
1
2
YSCY[15:0]
------------------------------
64
A = input line shift = 16
--
C = scale increment =
--
D = no offset = 0
Fig.29 Derivation of the phase related equations (example: interlace vertical scaling down to 3⁄5,
with field conversion).
2000 Mar 15
49
NXP [ NXP ]
