50i to 25p : Worth the trouble?

[andybiz_2005]

Hi all,

I'm going to shoot a corporate product launching very soon & there will be two videographers. Myself, using an AG-DVX100A & another using an AG-DVC20 camcorder.

I would love to shoot gorgeous 25p with my PAL camcorder & let the other videographer shoot normal 50 interlaced since his cam cannot record progressive frames.

I use Adobe Premiere Pro 1.5 as my main NLE & After Effects Pro 6.5 for special effects.

After uploading the AG-DVC20's footage to Adobe Premiere Pro 1.5, how do I use After Effects 6.5 to convert 50i to 25p? If it can be done, would the footage really become progressive 25 frames/sec? And if I mix my DVX100A's true 25p with 50i converted to 25p & render to a DVD using MPEG2-DVD format, will there be any stuttering in the footage due to the conversion?

Is it also worth the long rendering time in AE to convert 50i to 25p?

Thanks for your comments & advice.

Regards,

Andrew

[tcindie]

As far as I know you can just drop standard 50i footage onto a 25p timeline and it will be progressive. Pulldown removal is necessary for NTSC footage because of the different cadence. 25p is made by combining both interlaced fields of the 50i image.

With NTSC, 24p is spread over 60 interlaced frames... it's not an easily divisible number in that there is a bit of a remainder -- to eliminate this the 3:2 pulldown is used. What it does is spread certain frames across 3 fields rather than just 2, so that it can become a nice round number... it's a rather technical very mathematical process (and I suck at math)

But you PAL guys have it easier. ;) Guess that's worth having to pay a little bit more for the camera.

[VictorS]

Turning 50i into 25p is de-interlacing. When done on a computer, it won't look as good as shooting 25p. Shooting at a shutter of 1/25 will achieve the 25p look on a 50i camera w/o de-interlacing. Such a low shutter will create a good about of motion blur, so its best used in an environment will little character or camera movement.

[tcindie]

I think you'd be better off shooting 1/50 shutter if the intent is to convert to 25p.. if you're going for more of a filmic look, a 1/25 shutter is going to wreck that because it'll look like video. It's impossible for the shutter to be always open on a film camera, and the typical shutter angle is 180degree, which would be a shutter speed twice as fast as your frame rate.

[andybiz_2005]

Thank you all for your very helpful suggestions. I think the way to go is to de-interlace the 50i footage from the other videographer's camcorder (DVC20). If he sets his shutter to OFF, then it should be 1/50 by default. Any idea how to de-interlace footage using Adobe After Effects 6.5?

On the other hand, I may decide against shooting 25p & de-interlacing 50i to 25p because the duration of the shoot is total of 8 hours, from 1:30pm till 8:30pm. I'm not sure how many tapes will be used, but I 've got a feeling it will be a lot. I'm guessing that de-interlacing that much of 50i footage to 25p (the rendering time) in After Effects is going to take way too long. I just may decide to shoot 50i all the way. But I still want to weight the pros & cons of de-interlacing with AE.

Thanks again.

Andrew

[tcindie]

I think all you have to do is drop the 50i footage onto a progressive timeline, and then reinterpret it as progressive.. should work in the NLE. Give it a try on a short clip to know for sure, but you shouldn't need AE for that step.