pciGrabber-4x4
46
PHYTEC Messtechnik GmbH 2008 L-720e_0
To get a clear transfer of the data volume the maximum data rate of
the PCI bus must not be exceeded. In addition, a safety distance of
~15% to the 132 MB/s must be adhered to. So the maximum data
without overloading the PCI bus is 112 MB/s
Numbers of
decoders
RGB32
768 x 576
RGB32
640 x 480
RGB32
620 x 450
RGB16
768 x 576
Y8 Gray
768 x 576
1
44,2 MB/s
30,7 MB/s
27,9 MB/s
22,1 MB/s
11,1 MB/s
2
88,5 MB/s
61,4 MB/s
55,8 MB/s
44,2 MB/s
22,1 MB/s
3
132,7 MB/s
92,2 MB/s
83,7 MB/s
66,4 MB/s
33,2 MB/s
4
176,9 MB/s
122,9 MB/s
111,6 MB/s
88,5 MB/s
44,2 MB/s
Table 7
Example data volumes PAL 25fps
Numbers of
decoders
RGB32
720 x 480
RGB32
640 x 480
RGB32
580 x 400
RGB16
720 x 480
Y8 Gray
720 x 480
1
41,5 MB/s
36,9 MB/s
27,8 MB/s
20,7 MB/s
10,4 MB/s
2
82,9 MB/s
73,7 MB/s
55,7 MB/s
41,5 MB/s
20,7 MB/s
3
124,4 MB/s
110,6 MB/s
83,5 MB/s
62,2 MB/s
31,1 MB/s
4
165,9 MB/s
147,5 MB/s
111,4 MB/s
82,9 MB/s
41,5 MB/s
Table 8
Example data volumes NTSC 30fps
If the 112 MB/s are not exceeded an unproblematic data transfer is
possible. To see as in Table 7 and Table 8 it exists many possibilities
to reduce the volume of the data.
1.
Reduce the resolutio
2.
Reduce the colour depth
3.
Reduce the display regeneration rate
With the help of equation 1 can compute the data volume and decide
which settings for the suitable application suits.
