Selur's Little Message Board

Hey Selur,

I have some DV video that I'm deinterlacing and encoding, and I want to make sure I don't lose color information by using the wrong colorspace.  I read elsewhere that 4:1:1 and 4:2:0 are basically storing the same information in different ways.  Is that your understanding?

If using 4:2:0 is inappropriate for 4:1:1 source video, I'd appreciate any guidance.  I'm encoding in x265.

Thank you in advance!

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

Would 4:2:2 capture the extra 4:1:1 information without altering the video in a negative way, or would some undesirable conversion process happen?  I understand filesize might be a bit larger, but if 4:2:2 will retain the information I'd lose by going to 4:2:0, then I'd rather go with 4:2:2.

Yes, you could use 4:2:2 and enable 'Convert to target color space after source filter' and if all of the filters you use support that color space you could lessen potential losses.

Cu Selur

I and my family videos thank you