
Philips Semiconductors
Video Out
File: evo.fm5, modified 7/24/99
PRELIMINARY INFORMATION
7-11
co-sited chrominance coding. The U and V output pixels
that are at the same location as the U and V input pixels
use the corresponding input pixel values. The U and V
output pixels that are between the U and V input pixels
are generated using the (–3,19,19,–3)/32 filter. This is
If the input chroma is interspersed, a (–1,13,5,–1)/16 fil-
ter is used to generate the U and V output pixels that are
displaced by half a Y pixel from the U and V input pixels,
and a (–1,5,13,–1)/16 filter is used to generate the addi-
tional upscaled U and V output pixels that are displaced
by 1.5 pixels from the U and V input pixels. This is shown
7.11.4
Pixel Mirroring for Four-tap filters
The VO uses a four-tap filter for upscaling and for con-
verting from interspersed to co-sited format. One extra
pixel is needed at the beginning and two at the end of
each line that is processed by this filter. These pixels are
supplied automatically by mirroring the first and last pix-
els of each line. For example:
Output pixel 1 uses input pixel 1 to generate its value.
(same location, no ltering).
Output pixel 2 uses pixels 1,1, 2 and 3 to generate its
value.
Output pixel 3 uses pixel 2 to generate its value.
Output pixel 4 pixel uses pixels 1, 2, 3 and 4, etc.
.......
Output pixel 2N–2 uses pixels N–2, N–1, N, and N–1
to generate its value.
Output pixel 2N–1 uses pixel N to generate its value.
Output pixel 2N uses pixels N–1, N, N, and N–1 to
generate its value.
12 pixels.
7.12
OPERATING MODES
The Video Out operation is set by the MODE field in com-
bination with the OL_EN (overlay enable) control bit. The
MODE field determines video refresh, message passing
or data streaming mode. It further defines the video im-
age format and whether or not 2x horizontal upscaling
takes place. The OL_EN bit determines whether a video
refresh mode has a graphics overlay present. These
Chrominance (U,V)
samples
Luminance
samples
Input Pixels: YUV
Output Pixels: Y’U’V’
Co-sited Chrominance Output
U’,V’ = (–1,13,5,–1)/16
×U,V
Co-sited Chrominance Output
U’,V’ = (–1,5,13,–1)/16
×U,V
Upscaled Luminance Output Same
As Input Pixel: Y’ = Y
Upscaled Luminance Output Between
Input Pixels: Y’ = (-3,19,19,-3)/32
×Y
Figure 7-23. 2
×-upscaling of U and V with interspersed to co-sited conversion.
Table 7-5. Video Out Operating Modes
Mode
Function
Explanation
0000
YUV 4:2:2C-1
× YUV 4:2:2 co-sited, no scaling
0001
YUV 4:2:2I-1
×
YUV 4:2:2 interspersed, no scaling
0010
YUV 4:2:0-1
×
YUV 4:2:0, no scaling
0011
Reserved
0100
YUV 4:2:2C-2
× YUV 4:2:2 co-sited, horizontal 2×
upscaling
0101
YUV 4:2:2I-2
×
YUV 4:2:2 interspersed, horizontal
2
× upscaling
0110
YUV 4:2:0-2
×
YUV 4:2:0, horizontal 2
× upscaling
0111
Reserved
1000
Data
Streaming
Data Streaming mode, continuous
transmission of raw 8-bit data.
1001
Message
Passing
VO to VI message passing:
exchange of raw 8 bit data with
STMSG and ENDMSG signalling
1
Input Pixels: Y
Output Pixels: Y’
23456
13579
11
2468
10
12
Y’=Y1
Y’=Y2
Y’=Y3
Y’=Y4
Y’=Y5
2N–1:
Y’=Y6
Y’=F(Y1,Y1,Y2,Y3)
Y’=F(Y1,Y2,Y3,Y4)
Y’=F(Y2,Y3,Y4,Y5)
Y’=F(Y3,Y4,Y5,Y6)
Y’=F(Y4,Y5,Y6,Y6)
2N:
Y’=F(Y5,Y6,Y6,Y5)
Figure 7-24. Mirroring pixels in 2
× upscaling.