ALLIED Vision Technologies Stingray F-504 - Manual (Page 158)

Description of the data path
STINGRAY Technical Manual V4.4.4
156
Format_7 Mode_6 By default and without further remapping use Format_7 Mode_6 for

2 out of 4 H+V sub-sampling
The different sub-sampling patterns are shown below.
Figure 82: Vertical sub-sampling (color)
Note

The image appears vertically compressed in this mode and
no longer exhibits a true aspect ratio.
Figure 83: 2 out of 4 H+V sub-sampling (b/w)
2 out of 4 2 out of 8 (only F-145, F-146, F-201)
2 out of 4 H+V sub-sampling