Converting sRGB toYCbCr

I don't suppose we have a member here fluent in Linux, who can tell me a simple way to do this conversion, preferably with some sort of Photoshop (or more likely Gimp) action, and then to be able to convert the image back to sRGB after editing? I understand some Linux but not enough to do this. Any advice much appreciated.

Imagemagick is the generally used swiss army knife for fancy image conversions on Linux and can convert either way for you. This post here seems to give a lot of examples and workarounds for dealing with some unwanted colour shifts that can otherwise occur.

http://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=23404

And here giving examples of using this on a video stream

http://www.wizards-toolkit.org/discourse-server/viewtopic.php?f=1&t=15192

What editing program are you thinking of using that operates in YCbCr?

I've had a look at Imagemagick but it looks pretty complicated. Basically i want to be able to convert an sRGB file from my K5 to YcbCr, and then replace the luminance channel with the one from an infrared file. I also want to try replacing the luminance channel in a 665nm image with one from an 830nm image.
Gimp can edit YCbCr images, but I can't find any conversion tool available to convert the images in Gimp.

Yes Imagemagick certainly is complicated - that's so it can manage to accomodate folks with obscure requirements like yours

This really isn't anything I have tried myself, but there is a colour decompose plugin for Gimp that will separate out the luminance and Y channels and maybe be what you are looking for?

Thanks very much for that, I've just been looking at the plugin. I'll give it a try. It looks like it could be be useful for what I'm trying to do, which is basically to get the detail of IR and the colour of a normal shot in the same image. I've had some success with blending images using CMYK, but can't get the colours quite right.

Just downloaded that plugin, and it can decompose to YCbCr, just what I needed, I'll try it out!