In particular, the minimization of moiré - reportedly because they are no longer doing line skipping when scaling the image from the sensor down to HD resolutions - should make for a noticeable improvement in image quality. Hopefully that will flow on to all of Canon's other new DSLRs.
Here's what others are saying:
FINALLY the full frame Canon 1DX DSLR featuring “improved video” | Philip Bloom
We also now have a single clip length of up to maximum of 29 minutes and 59 seconds (that stupid EU tax rule stopping it going longer!) which is terrific news! Manual audio is featured and levels can be adjusted WHILST recording with meters on screen during recording!…but I still see no sign of the most basic feature we need…a headphone jack!!
Canon EOS-1D X | Jon Fauer | Film & Digital Times
The camera has two new compression schemes: intraframe (ALL-i ) that’s quick and easy to edit (but results in larger files), and interframe (IPB) for better data compression (smaller file size, more challenging to edit). SMPTE timecode can be generated as Rec Run or Free Run. Multiple cameras, digital slates, and external sound recording devices can be synced.
CANON LAUNCH EOS-1D X – A NEW GENERATION OF HDSLR | Dan Chung
| DSLR News Shooter
More importantly for me, it also promises improved advanced video features. Canon claim that the new camera will have significantly improved video image quality especially in low light. They say it should also reduce false colour and moire patterning, which plague the current Canon DSLRs like the 5D mkII. Also added is a choice of two new compression formats – intraframe (ALL-i ) compression for easier editing and interframe (IPB) compression for superior data compression.
Canon EOS-1D X overview | R Butler | DPReview
In addition the camera can keep track of how long it has been recording, using standard timecoding methods. There's also greater-than-ever control over the microphone input volume, with 64 manually selectable levels, auto and a wind-cut filter. It's also possible to mute sound recording while shooting.
Canon Launches Stunning New EOS-1D X | Dan Carr | Blog
It looks like this camera is not going to be available for quite some time. Possibly not until late March 2012. Why would they announce it so far ahead of time ? I’m not sure, perhaps they are preempting a Nikon announcement which they know to be coming soon.