I found this info and thought it may be worth adding hope some has not posted before it is helps
Standard VIDEO DATA RATE FOR CANON 550D
The EOS 550D in 720p (50/60) and 1080p (24/25/30) on each – at a bit rate of 45-49 megabits per second.
Usesing the Magic Lantern Bit rate adjustable setting as tested by Dave Pierpont on http://www.hv20.com
ML Qscale tests these are the data rates that I got after going through he Qscales unfortunately the camera would stop recording after only a few seconds at -14 thru -16
I would say its really only safe to record as high as -13 as of now...still testing stuff
-1: 8.8 Mb/s
-2: 9.6 Mb/s
-3: 11.8 Mb/s
-4: 13.9 Mb/s
-5: 15.0 Mb/s
-6: 17.1 Mb/s
-7: 21.0 Mb/s
-8: 24.3 Mb/s
-9: 29.6 Mb/s
-10: 35.3 Mb/s
-11: 42.0 Mb/s
-12: 48.0 Mb/s
-13: 56.3 Mb/s
-14: 64.2 Mb/s (flashes overheating icon and stops recording after 2 seconds)
-15: 67.5 Mb/s (flashes overheating icon and stops recording after 2 seconds)
-16: 86.7 Mb/s (flashes overheating icon and stops recording after 2 seconds)
Standard VIDEO DATA RATE FOR CANON 550D
The EOS 550D in 720p (50/60) and 1080p (24/25/30) on each – at a bit rate of 45-49 megabits per second.
Usesing the Magic Lantern Bit rate adjustable setting as tested by Dave Pierpont on http://www.hv20.com
ML Qscale tests these are the data rates that I got after going through he Qscales unfortunately the camera would stop recording after only a few seconds at -14 thru -16
I would say its really only safe to record as high as -13 as of now...still testing stuff
-1: 8.8 Mb/s
-2: 9.6 Mb/s
-3: 11.8 Mb/s
-4: 13.9 Mb/s
-5: 15.0 Mb/s
-6: 17.1 Mb/s
-7: 21.0 Mb/s
-8: 24.3 Mb/s
-9: 29.6 Mb/s
-10: 35.3 Mb/s
-11: 42.0 Mb/s
-12: 48.0 Mb/s
-13: 56.3 Mb/s
-14: 64.2 Mb/s (flashes overheating icon and stops recording after 2 seconds)
-15: 67.5 Mb/s (flashes overheating icon and stops recording after 2 seconds)
-16: 86.7 Mb/s (flashes overheating icon and stops recording after 2 seconds)