Why is it not giving my 24p export avi?!?

D

Daftman909

Active member
Ok, here is the deal.

When I export an DVI avi from Pro 1.5, I'm doing if from a 24p timeline with a 24pa video in a 24pa export setting for an avi but when I play this in media player classic, it is read as 29.97 and when I check the avi properties by right clicking in from the folder, it reads "Frame Rates: 29 Frames per second" (im not talking about the property option in player classic, i mean in the videos properties itself). And when i im[ort in After Effects 5, It STILL reads as 29.97! The ONLY time i get a video that reads "24 fps" is when I compress the avi to awmv format. What is going on here?? How can I edit a 24p video in After Effects or avoid interlacing while the video continues to say to me "I'm 29.97"??
 
Daftman,

24p Standard or Advanced is 24p embedded in a standard NTSC 29.97 AVI. You can interpret the footage in After Effects to drop the extra frame and work with just the 24 frames.

Josh
 
When you're exporting to 24pa, you're exporting to exactly the same format the footage came in on: 24pa, which is 24 progressive frames distributed over 60 fields or 29.97fps.

Let me explain:

The DVX captures 24 full progressive frames each second.

The NTSC television standard, which is used on miniDV tapes just like everywhere else, is 29.97 (30 to make things easier) frames each second. Each frame is made up of two fields (all the even horizontal lines of pixels counting from the top are one field, the odd lines are the other field) - hence the term "60i" for 60 interlaced fields per second.

So how is this possible? The DVX uses what's called a "pulldown" to distribute those 24 full frames over 60 fields. When Premiere gets that footage (whether you're capturing from the camera or you've already captured and the footage is on your hard drive), it takes a look at it and recognizes that there are 24 progressive frames buried in there even though the file is still 29.97.

It reverses the pulldown algorith that the camera uses, showing you those 24 frames that were originally captured and letting you perform edits on them.

When you export to wmv, you're taking those 24 frames per second and sticking them in a file that shows the viewer 24 frame per second - a truly progressive video file.

But you're trying to export to DV AVI (which is a particular kind of avi - a particular "codec"). The DV AVI codec that ships with Premiere only handles video in NTSC format (it does PAL too, the European standard, but don't worry about that just yet). That means it needs to be 720x480 @ 29.97 fps right? So Premiere does the exact same thing the DVX did when you were shooting your footage - it took the 24 frames and distributed them over a 29.97 timeline. So the file you export is, as you say, a 29.97 fps file.


So. What does this mean for you?

-> After Effects
If you want to edit your footage in After Effects, don't worry. After Effects can do the same thing Premiere can where it reverses the pulldown. Right-click on your footage in AE and go Interpret Footage. Choose 24pa (2:3:3:2), and "guess pulldown" (those are roughly the settings, I don't remember exact wording).

-> miniDV tape
If you're exporting to miniDV tape, you have to be in 29.97. Don't worry, it will still look like 24p footage when you watch it on TV. This is what happens to Hollywood movies on VHS - 24 film frames get distributed across 60 fields

-> DVD
You have two options. You can export to a 29.97 mpeg and burn to DVD, and everything will be fine on your TV.
-or-
You can make a true 24fps DVD (this is slightly more complicated usually). This will make it look a bit better on a computer, and it will save you some space on the disc. BUT: When you watch it on a regular TV, your DVD player is going to - you guessed it - use a pulldown method to distribute your 24 frames over 60 interlaced fields.

-> A non-DV AVI file
You can export a true 24 fps AVI file, just not one that uses the DV codec. You might want to use something like DivX for example if you want to put your movie online. No problem. DV AVIs are the only ones restricted to broadcast standards. You have to pick Microsoft AVI from the menu that currently has DV AVI selected, and then choose your codec in the next box.

Hope this helps. The 24p stuff gets confused a lot, it might be nice to have a sticky somewhere explaining all of this.
 
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Couldn't I just export my clip from Premiere as an uncompressed AVI at 23.976 fps, import into After Effects 5.0 in a composition set at 23.976, and after adding the effects, export as an uncompressed AVI at 23.976 and edited it Premiere?

I wouldn't need to go to "intrepet footage" since with the uncompressed, all frames are progressive and the 2:3:3:2 pulldown is already added. Since I use AE 5.0, this seems like the only way to add effects while keeping all frames at the right rate and quality.
 
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