SDA9400 Datasheet, PDF (18/94 Pages) Micronas – Scan Rate Converter using Embedded DRAM Technology Units

SDA 9400
6.3 Low data rate processing
The next figure shows the block diagram of the low data rate processing block. The input signal can
be vertically and horizontally compressed by a limited number of factors. In case of multipicture
mode the internal Multipicture controller will use both compression blocks to control the different
modes. Furthermore the input signal can be processed by different noise reduction algorithms to
reduce the noise in the signal. A motion detector calculates motion values for a motion adaptive
scan rate conversion processing. The movie mode and phase detector determines the information,
whether the input signal is a camera scene or movie scene. The global motion detector derives a
one bit signal, which indicates that the input signal is a still picture or a moving picture. The noise
measurement block determines the noise level of the input signal.
Block diagram of low data rate processing
NMLINE, NMALG NOISEME
MULTIPIC, PICPOS, YBORDER,
UBORDER, VBORDER
GMOTION, MOVMO, MOVPH
Noise
measurement
Multipicture
controller
YIN
UVIN
Line
memories
Vertical
compression
Horizontal
compression
Global
motion and
movie mode
and phase
detection
Spatial noise
reduction
Motion
detector for
scan rate
conversion
Temporal
noise
reduction
VDECON,
VCSNRON
HDECON,
HCSNRON
SNRON
NRON
Motion value to Memory
Y from Memory
Y to Memory
UV to Memory
UV from Memory
The different blocks and the corresponding parameters will be described now in more detail.
6.3.1 Vertical compression
The vertical compression compresses the incoming signal vertically by a constant factor given by
the parameter VDECON. For the Y and UV signal different filter characteristics are used. The
vertical compression can be switched off. For the multipicture modes the factors VDECON 2, 3 and
4 are necessary. Different filter characteristics are used for the factors 3 and 4. High quality vertical
compression for double window applications is possible, because the filter characteristic is
optimized for the factor 1.5.
The table below shows the relation between the parameter VDECON and the compression factor.
Input write parameter: VDECON
VDECON (1Ch)
0
1
2
3
4
5
6
7
Vertical compression off
Factor 1.25
Factor 1.5
Factor 1.75
Factor 2.0
Factor 3.0
Factor 4.0
not defined
Micronas
18
Preliminary Data Sheet