ADV7180
VIDEO PROCESSOR
STANDARD DEFINITION PROCESSOR
MACROVISION
DETECTION
STANDARD
AUTODETECTION
SLLC
CONTROL
VBI DATA
RECOVERY
DIGITIZED CVBS
DIGITIZED Y (YC)
LUMA
DIGITAL
FINE
LUMA
GAIN
CONTROL
LUMA
FILTER
LUMA
RESAMPLE
LUMA
2D COMB
CLAMP
LINE
AV
SYNC
EXTRACT
RESAMPLE
CONTROL
VIDEO DATA
OUTPUT
LENGTH
CODE
PREDICTOR
INSERTION
DIGITIZED CVBS
DIGITIZED C (YC)
CHROMA
DIGITAL
FINE
CHROMA
GAIN
CONTROL
MEASUREMENT
BLOCK (≥ I C)
CHROMA
DEMOD
CHROMA
FILTER
CHROMA
RESAMPLE
CHROMA
2D COMB
2
CLAMP
VIDEO DATA
PROCESSING
BLOCK
F
SC
RECOVERY
Figure 15. Block Diagram of the Video Processor
Figure 15 shows a block diagram of the ADV7180 video processor.
The ADV7180 can handle standard definition video in CVBS,
Y/C, and YPrPb formats. It can be divided into a luminance and
chrominance path. If the input video is of a composite type
(CVBS), both processing paths are fed with the CVBS input.
SD CHROMA PATH
The input signal is processed by the following blocks:
•
Chroma Digital Fine Clamp.
This block uses a high precision algorithm to clamp the
video signal.
SD LUMA PATH
•
Chroma Demodulation.
The input signal is processed by the following blocks:
This block employs a color subcarrier (FSC) recovery unit to
regenerate the color subcarrier for any modulated chroma
scheme. The demodulation block then performs an AM
demodulation for PAL and NTSC, and an FM demodulation
for SECAM.
•
Luma Digital Fine Clamp.
This block uses a high precision algorithm to clamp the
video signal.
•
Luma Filter.
•
•
Chroma Filter.
This block contains a luma decimation filter (YAA) with a
fixed response and some shaping filters (YSH) that have
selectable responses.
This block contains a chroma decimation filter (CAA) with
a fixed response and some shaping filters (CSH) that have
selectable responses.
•
•
Luma Gain Control.
Chroma Gain Control.
The automatic gain control (AGC) can operate on a variety
of different modes, including gain based on the depth of
the horizontal sync pulse, peak white mode, and fixed
manual gain.
Automatic gain control (AGC) can operate on several
different modes, including gain based on the color subcarrier
amplitude, gain based on the depth of the horizontal sync
pulse on the luma channel, or fixed manual gain.
Luma Resample.
•
•
Chroma Resample.
To correct for line-length errors as well as dynamic line-
length changes, the data is digitally resampled.
The chroma data is digitally resampled to keep it perfectly
aligned with the luma data. The resampling is done to
correct for static and dynamic line-length errors of the
incoming video signal.
•
•
Luma 2D Comb.
The two-dimensional comb filter provides Y/C separation.
AV Code Insertion.
Chroma 2D Comb.
At this point, the decoded luma (Y) signal is merged with
the retrieved chroma values. AV codes can be inserted
(as per ITU-R BT.656).
The 2D, 5-line, superadaptive comb filter provides high
quality Y/C separation in case the input signal is CVBS.
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