zr36067 ETC-unknow, zr36067 Datasheet - Page 46

• Manufacturer Part Number: zr36067
• Description: Av Pci Controller
• Manufacturer: ETC-unknow

AV PCI CONTROLLER
Appendix C: Fitting the Input Size to the Required Display Window
The ZR36067 can crop the input video and scale it down to
match any display size required by different applications, as long
as the required size is not larger than the original input. This
appendix provides some programming guidelines for proper
setting of the ZR36067 parameters involved in this process.
For better understanding, a typical example is detailed along
with the general explanations.
It is assumed that the driver software “knows” the following basic
parameters about the incoming video:
It is assumed that Ha is an even number. It is also assumed that
from knowing the video input format, the driver knows how to set
the following ZR36067 parameters, such that the entire active
portion of the video input would have been sampled:
The following equation connects HStart’, HEnd’, and Wa:
In the example, Hend’ = 841, HStart’ = 122.
The following equation connects VStart’, VEnd’, and Ha:
In the example, Vend’ = 249, VStart’ = 10.
The driver receives from the application software the parameters
that define the size of the rectangle, on the monitor, that should
Wt
Wa
Ht
Ha
HSPol
VSPol
HStart’
HEnd’
VStart’
VEnd’
Total width of the input field (i.e., in CCIR NTSC Wt = 858).
Active width of the input field (i.e., in CCIR NTSC Wa = 720).
Total height of the input frame (i.e., in CCIR NTSC Ht = 525).
Active height of the input frame (i.e., in CCIR NTSC Ht = 480).
The polarity of HSYNC, as defined in the ZR36067 data
sheet.
The polarity of VSYNC, as defined in the ZR36067 data
sheet.
The number of pixels, from the active edge of HSYNC, after
which the ZR36067 starts to sample the input.
The number of pixels, from the active edge of HSYNC, after
which the ZR36067 stops sampling the input.
The number of lines, from the active edge of VSYNC, after
which the ZR36067 starts to sample the input.
The number of lines, from the active edge of VSYNC, after
which the ZR36067 stops sampling the input.
Ha/2 = VEnd’ - VStart’ + 1
Wa = HEnd’ - HStart’ + 1
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be filled with video pixels. This is referred to as the destination
rectangle:
Obviously, in many cases the size of the video rectangle to be
displayed is different (smaller) than the size of the active video
input sampled by the ZR36067.
In the example: VidWinWid = 597, VidWinHt = 199. (Assuming
DispMod = 0, this means that the target “video window” in the
example is 597x398).
In such cases, out of the parameters above, the driver software
must determine the following ZR36067 parameters, such that
the quality of the displayed video is optimal in the sense that the
decimation factors will be as small as possible and the portions
of the input that are “cut out” (cropped) will also be as small as
possible.
VidWinWid
VidWinHt
hcrop1
hcrop2
vcrop1
vcrop2
HorDcm
VerDcm
HFilter
The number of pixels, that will be dropped from the begin-
ning of the active line. hcrop1 is not really a ZR36067
parameter, but it is useful to obtain HStart:
HStart = HStart’ + hcrop1.
The number of pixels, that will be dropped from the end of
the active line. hcrop2 is not really a ZR36067 parameter,
but it is useful to obtain HEnd:
HEnd = HEnd’ - hcrop2.
ning of the active field. vcrop1 is not really a ZR36067
parameter, but it is useful to obtain VStart:
VStart = VStart’ + vcrop1.
the active field. vcrop2 is not really a ZR36067 parameter,
but it is useful to obtain VEnd:
VEnd = VEnd’ - vcrop2.
Ratio of horizontal decimation. A number of HorDcm pixels
will be dropped out of every consecutive 64 pixels in an
input line. HorDcm/64 is the horizontal decimation factor.
Ratio of vertical decimation. A number of VerDcm pixels
will be dropped out of every consecutive 64 lines in an
input field. VerDcm/64 is the vertical decimation factor.
The horizontal filter through which the input is passed. The
filter is selected according to the horizontal decimation
factor that is first determined.
The number of lines, that will be dropped from the begin-
The number of lines, that will be dropped from the end of
Width of the video rectangle.
If DispMode=1 (single field display) this is the height of
the video rectangle. If DispMode=0 (emulation of inter-
laced video) this is half of the height of the video
rectangle (i.e., the height of one destination field).
Note that if DispMode=0 the vertical size of the video
rectangle must be an even number. This limitation might
conflict with applications that will require a video window
of a specific, odd vertical size. Such conflicts will be
resolved by the driver software, which in this case will
build a rectangle one line shorter than required, and
then fill-in the missing line (a-priori) with a background
color.