I had noticed that the Quicktime (H.264 @ 3500 kbps) movies I uploaded on ER looked a little different from the originals freshly exported from FCP.
Shiv Kumar told me that Quicktime movies get slightly degraded in saturation and blacks richness when played on Windows systems. Since ER's servers run on Windows, that is exactly what happens.
After some tests I came to the conclusion that by compensating on FCP by setting the saturation at 120 (from original 100) and the brightness at -11 (from original 0), you get a result pretty close to the one you intended to achieve.
This is not 100% accurate, it's just the result of some tests I've been doing and it works fine for me: thats why I wanted to share it. If you have more accurate settings please correct me.
Marco