Thursday, December 01, 2005

Canon XL H1 24F over HD-SDI

Lots of new support is coming for the new Canon XL H1. The full CineForm product line-up will be upgraded (free) to support direct capture and editing of the 24F mode of the new Canon HDV camera (along with the 30F and 60i modes.) Support for HDV capture of 24F was straight forward, as the CineForm Intermediate approach bypasses all the ugly messing around with native MPEG, we had that running a couple of days after our first prototype arrived. (Note to camera manufactures, it is very helpful to get prototypes for timely software releases -- are you listening Panasonic?) Canon's 24F HDV stream is converted to a 24p AVI and the results are excellent. Yet the Canon XL H1 adds interesting possibilities via HD-SDI; as the 24F is presented with 3:2 pulldown over 60i at 1920x1080. The challenge was to extract the pulldown on the fly and only capture the 24 progressive frames (all in software of course.) This is what we achieved today, such that a pure 24p stream could be recorded directly to the disk in 10-bit CineForm Intermediate, ready for 24p editing. For these first tests I used AMD dual Opteron 275 workstation, a very nice system. Yet the pulldown and compression only uses 50% on the CPU resources, so this 24F capture mode will work on any qualified Prospect HD Ingest workstation (i.e. Opteron 250s or better.)

Here is a WM9 1280x720p24 clip showing direct capture from the XL H1. Not very exciting -- just me waving for a few seconds. I will post a full 1920x1080 p24 image when I have something more interesting to show.

This capture mode allows for 24p ingest while bypassing the camera's MPEG compression and preserving the full 4:2:2 color space the Canon places over HD-SDI. As a result this feature will also appear in the Wafian HR-1. Capturing this way is great for any project where quality needs to be at a premium. The 24p extraction greatly simplifies the post workflow. While you can record to other formats like HDCAM/SR, D5 or DVCPRO-HD, the resulting data stream is still 60i; the pulldown will still need to be extracted (which I understand can be tricky or cumbersome using off the shelf tools.) So again we have a first.

8 comments:

Mark said...

Very cool! So are you getting identical time code over to disc with the video stream so we can actually use this in a work flow?
Please advise.

David said...

We haven't determined if Canon embeds timecode over HD-SDI, if it doesn't this may complicate some work flows. Yet the benefits in quality, particularly for effects shots, makes this aquistion style desirable even if camera timecode is not conveyed.

Jason Rodriguez said...

Easiest workaround with timecode is to use a timecode slate with the audio device as the timecode input (say a timecode DAT or some of the newer audio devices that can output timecode) and then change the timecode in Premiere Pro (I'm assuming you can do that, I know you can in other packages, but I've never tried in Premiere) to match the visual timeocode on the slate . . . I know, I know, a major pain for every clip, but that's the way it used to be when we'd sync audio and video dailes from separate film and DAT/Nagra sources.

Jason Rodriguez said...

BTW, one addition to the last post is that timecode would be time-of-day free-run, not record-run/preset/regen like you normally do on an ENG camera.

Anonymous said...

I can't wait for my new setup David!

I really want to see a 1080p frame with no compression from the camera...let me know when you post one!

-obin

clight@splendidlight.com said...

I didn't make it to NAB. Could someone please send me a link, or explain what the difference between 24p and 24F is? Thanks

Anonymous said...

What HD-SDI inport card did you use?

David said...

AJA Xena HS, LH or LHe was used for the capture.