Colour clipping when rendering

Hi,
Apologies another noob question.

I seem to be getting some clipping with some of the whites when I render to any video format.
In this image the left frame is rendered to tiff. That's more or less what it should look like. But when I render to mov, avi, mp4 etc I get the image on the right. Where it should be bright white, it's quite yellow.

colourClipping.png (619.89 KiB) Viewed 880 times

I'm slowly making my way through all the codecs to see if it's that, but nothing seems to help.

Does anyone know what I'm doing wrong?

(sorry this is a repost, I got an error when posting first time)

This looks to me like a color space / gamma / video or data-level issue.

I would render out a few frames of SMPTE color bars at the start of the project, then pull those frames back into Resolve and see if they exactly match the scopes of the material in the timeline. If they don't match, then you'll have to check the project video levels and/or color management settings and see what's causing the change.

Thanks Marc, I'll try that when I get back to my office. (On vacation now)

So are there seperate video levels/gamma settings when you render to video codecs rather than tifs,
?
The reason I ask this is that the colours seem fine when I render to a series of tifs. In fact, I've found a workaround where I render to tifs and then drop the tifs into Blender (of all things) and encode the tifs to an avi in there. When I do that, the colours in the resulting avi seem fine. (But I feel slightly embarrassed)