Exporting "24p" film for an NTSC project

S

sean90291

Veteran
Further to my queries about editing on a 23.976 Timeline:

Okay, so I now know I can capture my 24P Advanced footage into my 23.976 timeline and edit it there in the original DVX frame rate I shot it in. This will allow me to author true 24P DVD's, and get better quality as a result. But...and here's my question...

How do I use Avid to convert it BACK to the NTSC pre-pulldown footage for play on ordinary NTSC media like an interlace TV or what have you? I would like to author both 24P DVD's and create regular NTSC media copies of my films.

Any advice is appreciated!
 
If you're talking DVD, then I'm assuming you're using Sorenson Squeeze (which came with the non-academic Xpress Pro) for your encoding. If so, check this out.

http://www.24p.com/downloads/24p_DVD_creation.pdf

If you're using a different encoding app, then this is still great info, but might need to be tweaked a little.

If you're talking about going back to tape, then the Digital Cut tool will automatically reinsert pulldown for your footage.

Chris
 
I am using Sorenson Squeeze. Thank you for that document. It's got all the info I needed. I have also just read that "24P DVD's are universally playable all over the world (assuming that region zerio is selected in the copy protection options). They can be played back by both PAL and NTSC players. The player does the conversionin real-time as the playback occurs..." (from Marcus van Bavel's book "Shooting Digital"-- sales@dvfilm.com -- a book I have learned a lot from). So I don't really need to worry about converting back to NTSC interlaced.
 
I do wonder if my DVD authoring software is satisfactory for these purposes (authoring a 24P DVD). I'm using Ulead Movie Factory 4.0 to author DVD's. I wonder... If my Sorensen Squeeze is correctly configured to compress a 23.976 P MPEG-2 file, then does it matters whether Ulead's program is specifically set up to do 24P DVD's or not? Maybe as long as the MPEG-2 file is correctly compressed, then Ulead's program will just burn the DVD accordingly.
 
The DVD will need to be authored with a flag that tells the DVD player to insert pulldown for 29.97 display. Most authoring packages do this automatically. I'm afraid I can't say specifically if Ulead will be able to do this for you. I've never used their software. If worse comes to worse DVD-lab will do it. www.mediachance.com. DVD-lab is a very robust authoring tool and it's only $100.
 
An another option is do a Quicktime reference, then use TmpegEnc Pro 2.5 to create a MPEG 2 29,97 (with the 24P filter) and you should be able to build a DVD with that.
Otherwise, you must use a qualified DVD authoring software.
 
I use Sorensen Squeeze, which has A LOT of options for specifying 24p MPEG2 compression. I think, thanks to Krestofre referring me to that great Sorensen Squeeze article, I should be able to now use Ulead and other DVD authoring software to turn that 24p MPEG2 into a 24p DVD. At least, I'm going to find out!
 
use TmpegEnc Pro 2.5 to create a MPEG 2 29,97 (with the 24P filter)
Click to expand...

I may be wrong, but I believe that option will yield a 29.97 fps MPEG-2 file instead of creating a 23.976 MPEG-2 file and allowing the DVD player to handle the pulldown. While it is a viable solution, there is a difference between that and authoring a true progressive DVD.
 
Oh. Shite. This is complicated. Note that the article you referred me to at 24P says this:

**One of the advantages of working on a native 24p project (or 23.976) is the ability to create what is referred to as a “progressive DVD.” DVD has the ability to payback material that is 24p native and insert the 2:3 pulldown for NTSC viewing. This allows for 20% more program to fit on a DVD for the same bit rate, or a higher quality bit rate for the same length program.**

So, the article is definitely telling me how to make a true 24P DVD, I presume. And then it goes on to say:

**[M]ake sure that the FORMAT is set to NTSC...and this [automatically] sets the rate to 29.97. Even though the sources are 23.976 or 24p, this step indicates to the encoding process that the 2:3 flags need to be inserted into the MPEG2 stream to be decoded later by the DVDV player.**

Alas, are there any other gurus out there who wanna weigh in on this technical bit of esoterica? I'd love to know how to be sure I'm making a true 24P DVD (with my Sorensen Squeeze...not with any other software).

I'll marry the first man with the right answer.

Cheers mates!
 
Well, I'm already married, but if you follow the directions in the 24p article then you're are creating a true 100% dyed in the wool progressive DVD. The flag that the article refers to is necessary to allow the DVD to be universally compatible with all player and TV combinations.

Basically a DVD player has a switch that says "I'm connected to an interlaced TV" or "I'm connected to a progressive TV." That switch then looks at the DVD itself which has another switch. One that says "I am a DVD that runs at 29.97 frames per second" and another that says "I am a DVD hat runs at 23.976 frames per second." Then the DVD player merges the two to the best combination. I.E. if you have a progressive TV, then the DVD player will ignore the flag for 29.97 fps and playback without pulldown. If you have an interlaced TV then the DVD player will ackownledge the flag and insert pulldown for playback at 29.97 fps.
 
Okay. Then it sounds like the procedure at 24P is correct when using Sorensen Squeeze, giving a true 24P DVD which can then be "converted" by DVD players to play on non-progressive TV's.

And I'm Mormon so...
 
When setting Sorenson Squeeze MPEG2 setting to 29.97, it recognizes that the source is 23.976 so it will automatically insert the 2:3 pulldown flags during the encoding process. That is how that feature is triggered in Sorenson.

The same goes for the 16:9 flag. Once encoded, you should be able to pause and frame advance on a NTSC monitor and never see a flicker frame, but playback will be smooth with the 2:3 pulldown added back in. If so, you have a progressively encoded DVD for NTSC.

Michael
 
Michael, just for clarification, does that mean that all flagging is handled by the encoding software and not the authoring software?

Thanks.

EDIT: The reason I ask, is whenever I feed a 23.976 MPEG-2 file to my authoring app it always goes through a process of enabling pulldown, which I had assumed was adding the flag for authoring purposes. Maybe I have an authoring app that works in a non-standard way???
 
The flags are done at the MPEG2 encoding stage and not the authoring stage unless your authoring application also does the encoding.

The flags in the MPEG2 stream tell the DVD player to insert 2:3 pulldown in an NTSC environment from 23.976 material and to letterbox or not depending on monitor settings dedined on the DVD player.

I am also married, but I didn't know it could be this easy? All those years of dating!!!!

;-)

Michael
 
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