7
)
(
)
(
)
(
1
1
>>
+
Φ
=
∑
=
−
=
i
i
i
n
Rin
Ci
n
Rout
x
(
)
dss-E067
7
)
(
)
(
)
(
2
2
>>
+
Φ
=
∑
=
−
=
i
i
i
n
Rin
Ci
n
Rout
(
)
x
dss-E068
)
(
i
C Φ
dss-E069
Memory
LCD panel
Video window
Programmable
background default
color value
Video picture
dss-070
Public Version
www.ti.com
Display Subsystem Functional Description
(8)
For the vertical up/downsampling, the equation is R component with five taps):
Rout: R component output
: FIR filter coefficients
Rin: R component input
(9)
The pixel (n + 1) is older than pixel (n). The line (n + 1) is older than line (n).
NOTE:
The coefficients Ci() depend on the phase between input and output pixels.
NOTE:
If the 5-tap resizer is used for RGB16 and YUV4:2:2 picture formats, the width of the input
picture must be a multiple of 2 pixels and more than 5 pixels:
[21] VIDVERTICALTAPS == 1
[10:0] VIDORGSIZEX > 4 and even
shows an example of video upsampling.
Figure 7-76. Video Upsampling
Filter Description
The up/downsampling filter is a poly-phase filter with five taps and eight phases for the horizontal filter and
a programmable number of taps (three or five) and eight phases for vertical filter. The upsampling ratio is
up to x8. The downsampling ratio using 3-tap configuration is/2. The downsampling ratio using 5-tap
configuration is/4. The vertical filter is first applied to the encoded input pixel data; and then the horizontal
filter is applied on the resulting pixel values to generate the output pixel values.
shows the
computation for the R component in the case of three coefficients (vertical filtering). The same
computation applies to the G and B components.
1645
SWPU177N – December 2009 – Revised November 2010
Display Subsystem
Copyright © 2009–2010, Texas Instruments Incorporated
