This is pretty cool, though let’s all just admit right off the bat that the limitations are pretty major as well. This custom 3rd-party firmware is set to put out a release on 1/1/11 that will enable 4K recording (that’s 4096×2304) on the T2i, which is normally limited to 1080p.
The trouble? At that resolution, you can only record for six seconds. I’m assuming that’s due to running out of cache, but I could be wrong.
The max bitrates are around 175Mb/s, which is the highest supported by the fastest Class 10 SD cards on the market right now. A dual-card setup might be able to stripe it, but at the moment that’s the limit (and also part of the reason it’s not for the 7D or 5D at the moment, I suppose). The bitrate is so much higher because it looks like it’s not compressing the image data, which would have taken up quite a bit of processing power. So you won’t have that smeary H264 look.
And yes, you can use it with Magic Lantern.
Of course, it could be a hoax — they haven’t posted any verification video or whatnot, but we can all wait until Saturday, I think. I’ll update this post then with whatever breaks.