bt848kpf ETC-unknow, bt848kpf Datasheet - Page 42

• Manufacturer Part Number: bt848kpf
• Description: Single-chip Video Capture For Pci
• Manufacturer: ETC-unknow

F
Video Scaling, Cropping, and Temporal Decimation
32
UNCTIONAL
D
ESCRIPTION
When changing the programming in the temporal decimation register, 0x00 should
be loaded first, and then the decimation value. This will ensure that the decimation
counter is reset to zero. If zero is not first loaded, the decimation may start on any
field or frame in the sequence of 60 (or 50 for PAL/SECAM). On power-up, this
preload is not necessary because the counter is internally reset.
grammed to choose whether the decimation starts with an odd field or an even
field. If the FLDALIGN bit is set to logical zero, the first field that is dropped dur-
ing the decimation process will be an odd field. Conversely, setting the
FLDALIGN bit to logical one causes the even field to be dropped first in the dec-
imation process.
Examples:
When decimating fields, the FLDALIGN bit in the TDEC register can be pro-
TDEC = 0x02
TDEC = 0x9E
TDEC = 0x01
TDEC = 0x00
L848A_A
Decimation is performed by frames. Two frames
are skipped per 60 frames of video, assuming
NTSC decoding.
TIVE remains low for one frame. Frames 31–59
are then output followed by another frame of in-
active video.
Decimation is performed by fields. Thirty fields
are output per 60 fields of video, assuming
NTSC decoding.
odd field) of video starting with field one in
frame one.
Decimation is performed by frames. One frame
is skipped per 50 frames of video, assuming
PAL/SECAM decoding.
Decimation is not performed. Full frame rate
video is output by the Bt848.
Frames 1–29 are output normally, then AC-
This value outputs every other field (every
Single-Chip Video Capture for PCI
Bt848/848A/849A
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