Some tricky 24p questions...

[Haami]

Hello everyone, I'm new to this forum.

I'm excited about the possibilities of 24p, but have no prior experience with this format, although I am an avid MC editor by trade, for TV.

Here is my situation:

I'm going to Calgary on July 1st to shoot a short film on a brand new DVX100a. I have not used this camera previously.

In any case, I'll be bringing the tapes back to Denver with me to edit on Avid Express Pro -- sadly, no mojo.

I then plan to output to a DVCAM master, from which I can easily make Digibeta and DVD dubs for submission to festivals etc.

Now, It seems (and please correct me if I'm wrong) that while I can theoretically digitize 24p advanced footage into the Avid (and even edit in true 24p), without the mojo I cannot make a digital cut back out to 30i NTSC tape over firewire.

Therefore, since I want a progressive "filmy" look, it seems that I have to shoot in regular (not advanced) 24p mode (i.e. let the camera perform an internal 3:2 pulldown), and edit a normal 30i NTSC project in the Avid.

My first question is... Is this correct? I know it's basic stuff, but I'm new to this world, and I want to make sure my understanding is correct.

Now, I have a couple of additional questions for you wonderful folks...

1) I have heard that 24p footage, when pulled down to 30i, looks a little "juddery," or "flickery," especially on pans or other moves. Is this just the nature of the beast, or can anything be done either while shooting or in post, to reduce this effect?

2) I may need to make a dub to PAL for submission in a festival in Australia. Has anyone ever seen a PAL conversion of a 30i NTSC master that was originally shot in 24p? Could the conversion (from 24p to 30i and then to 25i) create some king of horrible extra flickering? Any thoughts or comments?

3) I want to integrate some animations into a few scenes. I plan to shoot a nice steady locked close-up of a notepad, and then make a basic animation of some squiggly cartoon characters running around on an alpha channel, and lay it over the video of the notepad. I want it to look like the characters are drawings on the paper, and have come to life. My question is: since the video layer will be 24p pulled down to 30i, what specs (frame rate, interlacing, etc.) should the animation conform to, in order to seamlessly blend in? Do I need to watch out for anything here -- e.g. do I have to somehow "match" cadence?


Well... that's it. I hope this generates some fun discussions, creative thinking, and hopefully some answers to my questions!

Thanks,
Haami

[MichaelP]

You can always make a progressive 24p DVD from the files in Xpress Pro. Export a QT reference from the project and encode into MPEG2 with the 2:3 pulldown flags (autmated in most encoding systems). You can send DVD to festivals which will maintain a ich hiogher quality (picture AND sound) than VHS. Mojo is not needed in any of this.

Judder is associated with pulldown frames when viewing at NTSC rates, or even in theatres - the two bladed shutter will make fast movements such as action or pans judder becuase of the low temporal frame rate. This has always been the case - there is a formula for pans based on distance covereed speed, etc in the American Cinematographer Manual (http://www.theasc.com/cgibin/store/acsstore.cgi). There is some very useful information in here for 24 frame production even though you are working in video.


You can encode PAL MPE2 from certain encoders from NTSC sources. You mniht want to give this a try. ALso, many PAL countries DVD players accept NTSC discs so you may get away with the same DVD. Check with festival submission rules before sending.

Animation is always easier when working at the frame rate of the sources - if the DVD route works for you, then work in a native 24p project type for your animations.

Michael

[Haami]

Michael, thanks for the reply.

Unfortunately my crappy laptop doesn't have a DVD burner.

That's why I was going to output by firewire to a DVCAM deck, and create a tape master that way. I can get free dubs made from that master to other formats, including DVD.

So... other than Mojo, is there any way to get a 24p project out of the avid and onto a 30i tape? Can the avid take a 24p clip and turn it into a 30i clip that can then be played out to tape?

[MichaelP]

That has been covered in past threads, but one way to do it is to export a QuickTime reference from the 24p project into After Effects, add a 2:3 expansion filter on it, and render it back out using the AVI DV codec for importing into a 30i project for output to DV.

Michael

[DVX100percent]

Actually, I had some audio sync problems encoding 24p quicktime reference files from Avid Xpress Pro, so, I ended up reimporting them into another 29.98 Avid project and encoding them this way. You can also output to tape this way (I assume). This is what I plan on doing for my next project as well. This way I still have 24p (advanced) footage when I need it, and I can output it to tape without Mojo (at 29.98)

Vlad

[Haami]

Thank you both very much for the replies.

Vlad -- So, you're saying I should shoot in 24p advanced, edit in 24p, then output the project (as what?), and re import it as a 30i project (how?)? I'm not sure I see how this would work... but perhaps, since you have done this, you could break down the process a little more, perhaps with a few specific details...?

If it works, this could be a great workaround -- you wouldn't need Mojo or DVFilm Maker to convert a completed 24p project to 30i.

Thanks friend,
Haami

[DVX100percent]

OK, here is the whole story (it might even be helpful to somebody to hear the whole story ;) ).

I shot my footage at 24p advanced, then edited it in Avid XPress Pro as native 24p project. My original intention was to make a 24p DVD out of it. This is where my problems started. I exported out of Avid as a 24p Quicktime reference file (however later I tried to output as a quicktime standalone with the same results). Then I tried encoding it but every time the encoded material would come out with audio drifting out of sync (not just out of sync but increasingly out of sync -- the longer the piece the more out of sync it gets).
After three days of experimenting I realized that if I uncheck "use Avid Codec" during quicktime export out of avid, it solves the audio sync issue, however video quality suffers greatly without avid codec, so that wasn't really an acceptable solution. So, as a workaround, I created another Avid project (this time 29.98 fps), then imported my 24p quicktime reference files into it, dropped them into a new 29.98 timeline and reexported the sequence (using Avid Codec). This time encoding worked fine with good video quality and no sync problems. I haven't actualy tried outputting to tape yet, but I don't forsee any problems, since the timeline is already 29.98 and shouldn't require mojo. Anyway, hope this helps, and if anybody has any solutions/suggestions to my original problem of encoding 24p footage out of Avid it would be greatly appreciated.

Vlad

[MichaelP]

The QuickTime Reference out of sync issue has been fixed in the last released update from what I understand. If not, it is in the one that is very soon to be released.

Michael