AK8854VQ Datasheet, PDF (56/95 Pages) Asahi Kasei Microsystems – Multi-Format Digital Video Decoder

[AK8854VQ]
VBIIMGCTL-bit: Settings for brightness and contrast adjustment status (ON/OFF) during VBI
VBIIMGCTL -bit
Status during VBI
Notes
[0]
Disabled
—
[1]
Enabled
—
VBIIMGCTL-bit must be set [1] when input signal is YPbPr or RGB.
7.24 Luminance bandwidth adjustment
Luminance bandwidth adjustment can be performed for MPEG compression etc. The band-limiting filters
for pre-compression limiting can be selected by the following register settings. Without these filters, the
frequency response of the luminance signal is determined by the decimation filter.
LUMFIL[1:0]-bits: Settings for luminance bandwidth filter
LUMFIL[1:0]-bits
Filter characteristic
[00]
No filter
[01]
Narrow
[10]
Mid
[11]
Wide
Notes
-3 dB at 6.29 MHz
-3dB at 2.94MHz
-3dB at 3.30MHz
-3dB at 4.00MHz
7.25 Sepia output
Sepia-colored output of the decoded signal can be obtained by the following register setting.
SEPIA-bit: Settings for sepia output of decoded signal
SEPIA –bit
Output
[0]
Normal
[1]
Sepia
Notes
—
—
7.26 VBI information decoding
The AK8854 decodes closed-caption, closed-caption-extended, VBID(CGMS), and WSS signals on the
vertical blanking signal, and writes the decoded data into a storage register. The AK8854 reads each
data bit in Request VBI Information Register(R/W)-[3:0] as a decoding request and thereupon enters a
data wait state. Data detection and decoding to the storage register are then performed which
indicates the presence or absence of data at STATUS 2 Register-[3:0] for host. The host can therefore
determine the stored values by reading the respective storage registers. The value in each storage
register is retained until a new value is written in by data renewal. For VBID data (CGMS-A), the CRCC
code is decoded and only the arithmetic result is stored in the register.
Signal type
Superimposed line
line
Closed Caption
Line21 (NTSC-M, J, NTSC-4.43, PAL-M, 60)
525
Closed Caption Extended Data Line284 (NTSC-M, J, NTSC-4.43, PAL-M, 60)
525
VBID
WSS
Line20 / 283 (NTSC-M, J, NTSC-4.43, PAL-M, 60) 525
Line20 / 333 (PAL-B, D, G, H, I, N, Nc, SECAM)
625
Line23 (PAL-B, D, G, H, I, N, Nc, SECAM)
625
The storage registers for each of the signal types are as follows. For storage bit allocations, please refer
to the respective register setting descriptions.
Closed Caption 1 Register, Closed Caption 2 Register
WSS 1 Register, WSS 2 Register
Extended Data 1 Register, Extended Data 2 Register
VBID 1 Register, VBID 2 Register
MS0973-E-01
56
2008/07