no -- not always..

how are you going to play it back and what was the source and what is the capabilities of the projector is questions that should be asked ..

You have to understand that if you use a DVD player - even a progressive DVD player, it does NOT output 24P ....
With 480p output each whole frame is refreshed every 1/60th of a second.

With 480I output, each field is updated every 1/60th of a second.

The Progressive DVD player shows the complete frames in this order: 1, 1, 1, 2, 2, 3, 3, 3, 4, 4 and so on (ntsc), PAL is 1,1, 2, 2, 3, 3, 4, 4 .........hence 2:2 pulldown

That is why often you see 'jerky' playback (well one of the reasons- there are several) .

If the source is film 24 and going to play it back on a progressive OR non progressive DVD player = render it as progressive with pulldown ...
The BETTER (most now) projectors will remove the pulldown -- or in most cases will determine the cadence or some other method to display progressive (all dlp and lcd projectors are progressive only for final output) ...


If the source is interlaced video - it should be rendered interlaced IF your projector is decent in the area of interpolation .. if it is not - you MIGHT want to deinterlace it - but really in most cases - just live with it ..

There is FAR to much of people wanting to de-interlace something that really should or doesnt need to be de-interlaced ...

For HD; " Progressive scanning (720p) produces a smoother, more film-like look, but a 1080i image actually contains greater detail. Though it has fewer lines, the native progressive scan format (720p) eliminates motion artifacts that originate in interlacing. For subject matter that contains a lot of rapid motion--Monday Night Football, basketball or hockey games, for example--720p will produce a clearer, more stable picture than 1080i. Alternatively, for subject matter that has very little motion, 1080i is capable of rendering more picture detail. And because 720p has the highest data bandwidth and horizontal scan rate, it usually means that 720p programming is converted or “scaled” to 1080i for transmission (it occupies less digital "space" than 720p)." (by Alan Lofft)


Interlacing can and will produce some artifacts - hard to get around that ...

it is to bad that 24fps has become what appears as the 'holy grail" of the video world -- because it is really such a poor frame rate - and only in use to save money (true - look up 24fps history) , not for better quality ...

That is why high end film is shot and played back at 30-60fps ... The difference is outstanding ...

so .........

having covered SD-DVD playback - what about HD and/or PC playback or an HD server?

Well going back to SD -DVD , you may find that the projector only does proper video processing when you use the component inputs and not using the RGBHV inputs .. conversely - DVI in is a crap shoot ....

High(er) end D-cinema projectors use SDI in and also (in some rare cases) a special non-consumer encrypted HD input ...

So you have to check what your HD server/player/output can output in terms of signal first and match that to the projector you are going to use -- since as much as possible you want to render to the native panel panel resolution of the projector - factor that in also ...
Add to the mix - you can have anamorphic lens on projectors and of course there is a whole slew of different aspect ratio 's in projectors .. 720P right now seems a good all around choice IF you have the bandwidth and output to carry it off - personally I like using 1080P30 IF you can find a playback source for this (there are) and the projector has very high quality scaling or you are using a outboard scaler ... or you are using a 2k projector (ahh - best choice) ..

There are even other differences and factors between
projectors and playback that ive only just touched on here .... Iv'e designed 100's and 100's of such systems and i'm still getting surprised at times ...



what i am getting it is that the varibles are many and it is best to test your setup ....