Preserving 4:1:1 colorspace from DV video source

[Selur]

In the case of 4:1:1, for every 4 luma samples horizontally, there is only one chroma sample (either U or V), and for every luma sample vertically, there is one chroma sample. In contrast, in 4:2:0, for every 4 luma samples horizontally, there are two chroma samples, and for every 2 luma samples vertically, there are two chroma samples.
=> they are not storing the same information.
4:2:0 has more chroma information compared to 4:1:1, where as 4:1:1 has more luma information.
That said, usually the difference it not visibly noticeable.

Cu Selur