My 2 Cents worth on this is , HDMI
Why not Capture the HDMI ? it can be clean (just need to toggle off the over lays)
According to the
Feature comparison matrix under "Display" CLEAR_OVERLAYS
Much better the h264 by a long shot.
Rent yourself a
Atomos Ninja I know in Canada the rental is cheap
Atomos Ninja2 Portable Field Recorder $45.00 for a weekend CND .
The big bonus with that you get straight to 10bit ProRes422HQ etc... which is worth it for the cost.
But be aware that the picture style profile will effect the out come of the image , not like raw where it doesn't matter.
I do this a lot with my 5d2 with my 1st gen atomos ninja & I usually go for a neutral (Semi Flat) picture style or what ever you like .
Now if all is equal with all cam that ML supports , you should get a uncompressed 4:2:2 8bit 1650x1080 60i/24p (24p embedded , need to do a 3-2 pulldown 60i->24p)
At least the t2i & 5d2 do , but the t5i may get you full 1080p never tested one thou you would have test to be sure.
To over come the Liveview timing out , do one of 2 things press the "half shutter button" to refesh Liveview .
Not to practical as you my bump the cam or move it , the other way is to make the "half shutter button" Sticky
go in to ML menu and make the button sticky.
You will still need to plug in a audio input e.g. Mic. to the ninja , as the hdmi has no audio on the canon dslr.
hope that helps