mRAW on canon 7D

how does mRaw work? does it just combine multiple pixels into one, does it take the photo at full raw resolution and lower the resolution afterwards, or does it use another technique?

if it combines pixels in the censor wouldn't that effectively lower the pixel density and maybe lower noise?

and if it takes a regular RAW picture and then combines pixels after taking the picture wouldn't that take up more camera processing power for the only benefit of saving space on the CF card

does a 10 mega-pixel mRAW shot have less noise than an 18 mega-pixel RAW shot?
if not can someone tell me if there are any benefits to shooting mRAW other than smallerimage size?

I read somewhere that it does do pixel binning, meaning a 10 MP shot would be less noisy, in theory, than an 18mp one

tongsy wrote in post #10917341
I read somewhere that it does do pixel binning, meaning a 10 MP shot would be less noisy, in theory, than an 18mp one

did you read this somewhere reputable? because I read the same thing on some dpreview and other threads and while some people seemed completely sure that it did pixel binning just as many people were 100% sure that it did not.

I sometimes shoot sRAW1 at high ISO with my 50D.. It could be my imagination but at times I feel the sRAW1 images are cleaner than the RAW images..

https://photography-on-the.net/forum/showthre​ad.php?t=762492
Nicksan did a side-by-side here ^^^^^ which throws some light on the subject, and from my research the sensor is only partially used, which means that some pixels are switched off...though I don't know which ones!!!!!!
Regards,
Simon

I've forgot where, but somewhere Canon claimed that all smaller resolutions, be it movie or still, are computed by beginning with the full image, then applying some non-disclosed more or less clever algorithm to reduce them.
Some people have figured out that the smaller RAW images aren't encoded in the same way, but an inferior one.
I don't remember the links to the references, so this is just out of the top of my head.