Is Vegas 4 pulldown removal accurate?

mikkie wrote on 5/2/2003, 7:44 AM

Assuming you're going out to DV, SOFO has said it's very accurate. On the other hand, if your captured footage is a movie, stuff can get complicated - they don't always use the same telecine method throughout. I have read of a few folks who do go through and check the result of IVT in other software, tweaking it as nec, but in my experience when the video's playing at 24 fps you're doing D___ good if you can spot the occassional missed frame - much more likely to spot problems with the original conversion from film.

If you're going from your own 24p source, you can skip the whole thing and just stay 24p.

"Is there any way of verifying the accuracy against the original 24p source?"
If you had the original 24p source, you could I suppose verify the accuracy going frame by frame, but why would you - just use the 24p to start with.

EW wrote on 5/2/2003, 11:33 AM

I plan to shoot on 35mm film. The procedure I want to try is this:

1) Transfer 35mm to 24p HD tape.
2) Get an NTSC DV (or VHS) dub.
3) Have Vegas do pulldown removal to restore the original frames.
4) Edit on a 24p timeline.
5) Conform the HD (and film) to the 24p Vegas cutlist.

If Vegas can do a frame-accurate pulldown removal from the VHS (or DV) dub, and preserve matching TC between the HD source and the Vegas 24p timeline, all will be okay, I think.

And it sounds like Vegas 4's most accurate pulldown comes from AG-DVX100 advanced mode footage. So, I also wonder if the process used on the Panasonic could be implemented to transfer the 24p HD to a DV source. I sent Panasonic an email.

vitalforce2 wrote on 5/2/2003, 12:04 PM

From what I have read on the forum, Vegas 4.0b is tuned most closely to the 24p "Advanced" setting from the Panasonic camera, which is a 2:3:3:2 pulldown rather than 2:3:2:3, making for a smoother reverse telecine. In other words, the DVX100's in-camera hardware telecines its 24p signal into 60i before it goes through the firewire into the hard drive, using either of those two settings (switchable as F5 or F6 with a wheel on the back of the camera), but Vegas can be set to detect the coding and reverse the process, creating a 24p timeline. So if set up via hardware which can telecine the 35mm frames to DV (avoiding analog tape format), a 2:3:3:2 cadence allows a smoother transition because there is only 1 frame (#3) being removed from each sequence. This is the limit of my knowledge. I will stop now.

SonyDennis wrote on 5/2/2003, 4:56 PM

EW:

The answer to your first question is yes, Vegas does perfectly accurate IVTC on DVX100 footage with constant cadence.

Vegas does not do IVTC on arbitrary video, but if you marked a constant cadence DV stream with an accurate 24p or 24pA "shooting mode" header, Vegas would pick it up as 24p.

You might start to find film transfer houses willing to create DV files with "shooting mode" headers that would allow DVX100-compatible NLE's (such as Vegas 4) to do IVTC automatically on the footage. I am not yet aware of any, but it would be worth asking them. The more people ask for it, they might start doing it.

This would work for both "traditional" 2-3 and "advanced mode" (24pA) 2-3-3-2 pulldown. A good thing, since you might have to live with 2-3 tranfer pulldown for a while since I don't know how hard it would be for a telecine machine to be converted to do 2-3-3-2 pulldown. The advantage of 24pA as a source format is that it's more efficient to read and write, and has less recompression due to the split frame. 2-3 is what you want for a final video transfer.

I hope you plan on accounting for the 0.1% speed difference somewhere in that workflow.

///d@

db wrote on 5/2/2003, 5:53 PM

i called a few telecine house in SF and LA .. none do 2 3 3 2 nor have ability to di it . all said i was 1st person to inquire about it - all have heard of the panasonic 24pA and thought 24pA was developed by panasonic so they hold rights. BUT as ALL said if they get enough request it might be worth looking into !!!

EW wrote on 5/3/2003, 12:22 AM

Thank you SonicDennis,
Please explain the 0.1% speed difference?

editor3333,
The tranfer to 24p HD is to give an option of creating a high-quality finished project on HD or film.

SonyDennis wrote on 5/3/2003, 11:27 AM

I am talking about the (approximately) 0.1% speed difference between true 24 fps and the 23.976 fps of 24p DV, due to the 29.97 fps NTSC standard. When your film is transfered to video, it will be slowed down 0.1% to account for this. Just be aware of it, and decide if you need to do anything special in all of your calculations. Wouldn't it be cheaper to rent HDCAM gear and shoot HD, and then edit a proxy DV transfer?
///d@
P.S. 23.976 is actually a repeating fraction - 24,000 over 1,001 to be exact.

EW wrote on 5/3/2003, 6:07 PM

Thanks for that explanation. Shooting HD (instead of film) isn't necessarily cheaper, and the folks I'm working with felt we'd have more flexability (especially in terms of large-format exhibition) if the project originated on film.

Kirk wrote on 6/12/2003, 5:13 PM

Definitely shoot film if you can. I would not transfer everything to HD if you are going to also transfer to MINIDV. Consider this maybe: You transfer your dalies to minidv with a letterbox, and a timecode/keycode burn. You've just saved at least $4000 on transfer to HD, not including tape stock(I think $75-unit now?)! Buy a camera, or deck and have the post house transfer to it, with the flags you want for import. You'll have a deck now for the edit. Cut, conform the neg. If you want an HD master, telecine the movie now. 100min, instead of 8+ hours. You'll be able to Color Time the movie much more accurately, and spend less$. The exception is if you have free telecine, and HD equipment to view dalies to check focus issues, production design, make-up, etc. Good luck. And if you need a DP.......

SonyEPM wrote on 6/13/2003, 9:33 AM

EW: I'll be honest. If you have the budget for shootin' 35, use AVID Film composer for the cutting. This is the right tool for the job and currently the only shipping tool that is guaranteed to work. Any other choice at this point in time is a crapshoot- trust me.

Ok and the flipside: If want to use Vegas for this, get the film edge codes (and any timecodes) burned on to every piece of video reference material- all dubs should have the original source frame info burned in. You could always do a "pencil" (manual) edl, might take you half a day to type it all in but that's cheaper than showing up in an HD room with a bogus edl. Test the entire post workflow from start to finish before you commit to this.

Good luck-

EW wrote on 6/13/2003, 4:25 PM

Thanks for the replys. We are about two weeks away from locking the script, and will then start pre-production.

The option to do miniDV transfers, THEN only transfer the final cut to HD is a very useful idea. I will suggest it to the other producers.

Also, if the budget allows, we probably will end up using an Avid system to facilitate matchback.

But, boy if Vegas had that capability... By the way, what is making that so difficult to implement in Vegas? It would seem that the mathematical conversion formulas have already been worked out for years. Does if have to do with the software design of Vegas itself vs. the way Avid as a system was designed?

filmy wrote on 6/13/2003, 7:38 PM

I just have to toss in my few cents - VV would need an EDL that would be an standard in order to work in all of this. it doesn't - I am not aware of any negative cutter that you can take a VV EDL too and have them make any sense out of it. So that is problem number 1.

Doing it by hand is fine as long as you have the time. But it would be a long tedious job for a feature film. As a rule of thumb you should always have a window burn done on the dailes anyhow. Certianly what you edit with on a system like VV would need to have the edge numbers and TC window on it in you are going to have a negative cut done. Also keep another thing in mind that has not been mentioned - you will need to cut everything in reels. This is extremely important if you are going to cut negative and have a print made. On the average a reel should be no longer than 10 minutes, and you need to account for leader on ether end. You can't just go and toss a negative cutter a 90 minute video and say "here, do a matchback of this" and than go to the film lab with a 90 minute audio track and go "here sync this up" Sorry, it doesn't work that way.

It sounds like, on the one hand, you want to do this solo - I mean you want to do the edit, cut the audio, turn out a complete EDL and do a match back for the neg and hand over that to a neg cutter and let them at it. And, maybe, take the EDL and do to an online session with the HD Master as well. And, again, this is something you can;t do with VV. Even if you do make a text EDL out by hand you can't just dump that onto a floppy and hope it reads - it needs ot be on a formated floppy for CMX or Grass Valley systems. I am not sure where you are at but if you might want to check with your neg cutter to get the exact specs. I am sure Dick over at Magic Film and Video would help you out, they are one of the first houses that started offering video dailies and matchbacks as far as negative cutting goes.

D/Vision came with a bunch of little DOS based things and if I get a chance I will dig out the disks and see if they work still, keep in mind that D/Vision was a DOS based system in the days of Windows 3.1. One of the utilities was an edge number logger that you could enter in the first edge number and the start timecode at that number and than the end number(s). You combined that with the EDL and it would do a basic matchback for you. Also there were a few formating utilities - it would format a floppy for CMX, Grass Valley and...I forgot..Sony maybe... EDL's. D/Vision did not have good looger at all so you really had to use a third party logging utility if you wanted to do a detailed one. For TimeCode input we had (Still have it) an AEC box that hooks up to a PC and would read incoming VITC or LTC.

I am telling you this because you don't *need* to get an Avid to do a matchback. You can hire someone to do it - just like to good ole days. :) I still think of editing as editing. You do the edit and someone else does the Color Correction for video, someone does a negative cut for film, someone does the titles, someone does the audio post, someone does the online...and so on. It is nice to do it all but really there isn't yet a system that can really do it all. Every system does something better than the other - Saddly VV leaves out important things like EDL compatability which would at least be a needed first step in the process. So you know, if you have lots of money to blow to get an Avid just to be able to do an EDL and Matchback go for it. Or you could use an NLE that does support EDL's and than take your cut reels along with EDL's to a negative cutter for the matchback.