ProspectHD and pulldown 720p60 mxf to 24p
 

I'm a current ProspectHD user and I'm considering the Convergent Design's Nano Flash as an acquisition device from the HD SDI output of my JVC HD250. The HD250 can put out a 720p60 stream which would be best for pulldown processing since the Nano doesn't currently support pulldown in-box. They do plan on implementing pulldown features in the future, but future can mean a long time from now and who knows what kind of pulldown they'll be able to pull off.

what I don't know, and can't currently test because I do not have HD SDI capture ability, is whether or not ProspectHD can perform such a pulldown with great results. the HD250 can create Varicam flags on the output stream which should make the pulldown easier.

Anyone have experience with this? Any input would be greatly appreciated.

I hope I get this right....

Your camera shoots 24P native and also 60P native... most of us have cams that shoot
60i.. interlaced... our 24p is in the 60i wrapper and you have to pull down the frames to make 24P...

my understanding of 60P is that its for slow motion work... you overcrank (60P) the footage and slow it down on the timeline for the smooth slo mo footage that 60P gives you.

Thanks for the reply, Ray, but I think you've misunderstood my question.

The HD250 is capable of real progressive 24p recording to tape and to Direct-to-disk recorders. The HD SDI output was originally designed for monitoring and broadcast implementation and is compliant to HD standards, and the only standards supported as input by ALL HD displays (in North America) is 1080i60 and 720p60. That's what it is capable of outputting.

I know from experience with the HDV footage that ProspectHD is capable of turning the 60p into 24p slo-mo footage. What I can't test at this time is whether or not it can pulldown 60p footage to normal speed 24p footage effectively.

I'm an indy filmmaker gearing up for another project. What I want to do is bypass the HDV compression to capture the full 4:2:2 color space and avoid low light artifacting by recording the HD SDI stream then converting from the 720p60 to 24p. It will be nice to have the 60p stream recorded for any possible slo-mo that I might want to use in the project, but ultimately I want a 24 frame project.

I shot my last two projects in HDV and with AspectHD's and prospectHD's help was pleased with the results, but what I'm really after is a step up in image quality in low light and compositing applications.

Chad I dont know if ProspectHD can do 60p to 24p same-speed - my guess is that it could but the Cineform guys might chip in here.

However 60p to 24p should be an easy script to write using avisynth, so a Virtualdub/Cineform codec/Avisyth script workflow would be an alternative to consider. I can provide more details if you decided to head in that direction.

Thanks, Graham. That's an interesting idea for a work-around. It's been a long time since I've played with Avisyth and I was pretty unsuccessful at it. Don't knock yourself out about it, but if you have some details I would be interested.

Convergent Designs is promising a pulldown feature for the XRD and the Nano. It's in testing now. Maybe this will all be unnecessary but it would still be nice to know if Cineform could do it. If only I had a AJA card...

I'd ask Convergent Designs again about your understanding of what they plan to do with
24P pulldown..

I'm almost positive that they will tell you that they plan on offering 24P pull down from
a 60i stream... and not from a 60p stream. pulling 24P out of a 60i stream is much
different than taking a 60P and making it a 24P...

Chad - is there a tinypiece of footage you could upload somewhere that I could test a script on?

Sorry, Graham. I've been away from the web for a few days.

Thanks for the offer, but no, I don't have any footage, at least in the XMF format that the Nano would use. The best I could do would be the HDV 60p the camera would capture to tape. Of course that might be enough for you to test it. Let me know if that would work.

Hmmm. If I understand you right, your plan is to have the camera set to 24P mode, but capture the SDI output which will be in 60P (for monitor compatibility).

So I guess the issue is whether the SDI 60P has the same structure as the HDV footage laid down would have when the camera is have actually set to 60P ... do you think it does?

Thanks, Graham. I'm thinking it's not worth the test if we're not working in the format I'm interested in. I really appreciate your time. That's the thing about DVinfo, good people.

Converent Designs has just implemented a pulldown for 1080i60 in their new firmware. They promise a 720p24 from a 60 stream in a later firmware update. I think I'll just hold off for a while. My new project doesn't start shooting until the spring. Perhaps there will be more info on the subject in a couple of months.

Thanks again.

No problemo - hope it works out.