can FCP properly interlace progressive material?

> more specifically I was wondering what the best settings are for compressor to create
> a broadcast quality master 1080i 29.97 file from the original 1080 24p file.

The short answer is, if you have a 24p source, you don't produce an interlaced file for a master. There's no point. The 24p source file can be used as the source for both tape output using a capture card, and as the master file for exporting digital files (eg. H.264 screeners and web output).

I disagree with strypes that adding pulldown with hardware and software produces the same results. Most of the people I've ever worked with agree that adding pulldown with hardware (such as a capture card) yields better results. But you already ruled out that option, for whatever reason.


www.derekmok.com

Unless the hardware has a sophisticated algorithm to blend and selectively blur the fields (eg. the Teranex), it's basically the same operation- repeat frame A over 3 fields, frame B over 2 fields, C over 3 fields, D over 2 fields, etc... In other words, every 2nd or 3rd frame, you split the fields and combine 2 images. This is a simple and lossless process if your input and output source is uncompressed. If you are working with compressed images, the software will have to render every second or third frame. When done via hardware, it is the same process, except that the signal is uncompressed (SDI).

Problem is that FCP uses a 2:2:2:4 pulldown (repeat last frame twice) when you drop a 23.98 file into a 29.97 timeline, which is stuttery because the pulldown is not as consistent as a 3:2 pulldown. Compressor can do a 3:2 pulldown, and so can After Effects or the free JES Deinterlacer. The Kona card does better up/down conversion than FCP, whereas optical flow in Compressor takes ages to render, and it often contains artifacts. Hardware or software, if the mathematical operation is exactly the same, the trade off is time. Hardware chips are programmed to do the calculation in real time, while softwares rely on the speed of your processor. For operations such as adding or removing pulldown, it is trivial, and machines are able to do the processing in real time.

Regarding jitters, jitters do not happen when you add pulldown to an image. They often happen when an inferior pulldown is used, such as a 2:2:2:4 or 2:3:3:2 pulldown (interlace 1 field in 5 frames), because these pulldown patterns are the least consistent. On the other hand, you may get jitters on fast objects when you deinterlace the image (i am not talking about removing pulldown), this happens when an image that requires a higher sample rate is under sampled.



www.strypesinpost.com

You have to produce a 29.97 interlaced deliverable if you are delivering for broadcast and it is in the specs. But as I mentioned, you don't have to worry about it, because that will be handled by the card on the way out to tape. If you are delivering file based media, you can run it through Compressor or Episode. For Compressor, use "fast" or "fastest" for the time based option in frame controls, but make sure you set output fields to upper first, and set the frame rate to 29.97 in the codec settings. You can do your encoding pass in the same step.

If you have the budget, you can run the video through a hardware standards converter such as the Alchemist or the Teranex. The Alchemist will cost more, but it uses motion compensation, which results in smoother and clearer resampling of your signal.



www.strypesinpost.com