Lossless Predictive 4:4:4 outputs lossy 4:2:0?

[GenericPerson#375]

Can someone explain this to me? What is the point of a lossless profile/mode when it outputs a lossy format? I feel like I'm missing something that's supposed to be obvious...

[Deleted User 11865]

There is no profile for lossless 4:2:0, so whenever using lossless, x264 uses the High 4:4:4 Predictive profile; since we only support 4:2:0 internally, that's what we feed to x264. If your source is also 4:2:0, then it will be encoded losslessly (compared to the input); if your source has another colorspace, then it will indeed be converted to 4:2:0 (a lossy process), then the 4:2:0 intermediate will be encoded losslessly.