i or p this is the question

or ... 

Deinterlace or progressive! 

Just once! I usually don't participate in any 'quality' debate - imho, AVCHD on a Mac delivers superb results. period. 

"… but I do have those lines/jaggies/zil quality…" 
yes, YOU have! 
And I show and tell you why … and why a lie is better than the truth: 



The Original: 


This is a 200% playback of an 1080i recording, playback with QTplayer.app on a Mac - 'lines'. Yes, YOU did choose this … 'funny' interlacing, you listened to the shop-guy, "… but 1920 is obviously 2.5 more res than 720, isn't it? sign here, Sir, to sell your soul …". Now, live with it. 




A Computer isn't meant for interlaced. 

Any TFT, Plasma, LED can not display interlaced, that a is against the rules of Physics. 

Interlaced is ONLY displayed correctly on a Tube, when the beam-of-electrons hits the phosphor, which after-glows, so your eyes are tricked to see a solid pic instead of two 'woven' pics. 


"… but THEY said, interlaced is better for fast motion …" 
no, it feels better


there're many methods to bring an i-pic to display on a non-tube, basically two: 
• drop one field 
• blend both fields 

Here's our recording (a piece of), 1920x1080 .. looks good? 
no, because it is 1920x540(x2) … 

one field missing, the missing other lines 'replaced' by double-ing the other ones = half vertical resolution = but no 'steps', jaggies, lines, younameit

"… but skipping one field isn't 1080, eh? more kinda 540, eh? …" 
correct.
and 540 is even less than 720 ...- tell this the salesman.

2nd method: blending. 


both fields get its lines doubled (as mentioned in method#1) = 60 'frames', then every pair of frames get blended, then fps halfed to get the 'original' 30fps (outside US: 50/25)
in result: 'ghosts' = this is as I call it.. esp. vertical contours trail a ghost behind it. 



"… but on my telly it looks better!! …" 

On any modern display, aka FlatscreenTV, tons of electronic try to weave the two field together, a connected HDefcam or your satellite dish delivers. some use a display-framerate of 200HZ (your video is 25/30) .. so, it HAS to blend .. fields and frames. 

in result, instead of a stream of single, crystal crisp frames, we get offered a smashed, smeared, blended, motion-blurred picture - which we recognize as 'better', more comfortable for the eye.

Any recording with fast horizontal motion, e.g. football, looks, or say feels 'better' with blurr. On the other side: without motion-blurr, a pic looks ultra-sharp, clear, crisp.



other example, same source, same scenery, concentrate on the windows of car: 

Original 





TopField only 





Blended 





btw: do you notice the 'washed out' letters on that sign on the right? the resolution is missing. ANY deinterlacing, skip-field or blending, kills vertical resolution. 


"… but I do have a CRT/Tube and I want making DVDs from my HDef recordings! …" 

just do it. 
a videoDVD has by standards 720 x 540 resolution. which is - tadahhh - vertical HALF of your 'Full'HD1080i ..  
so, forget any deinterlacing, top-field, bobbing, processing - your HDef content loses half its vertical resolution anyhow on a DVD! 


" … but I want 1080i on export from iM! I want! WANT, WANT, WANT!!! …" 

use the Export with Quicktime feature in iM's Share-menu. 
and spend some time reading on my other site … : 
the imovieexportproject


" … so, what do YOU do, Karsten?

I'm recording in 720p, import in 'Full', have no trouble with lines, convertings .. 
and due to using a slow shutter speed on my cam, I can get smooth, stutter-less video too….
when I want motion-blurr, I set the shutter-speed of my cam as low as possible, close to 1/30th - but we now enter the Wonderful World of Photography .. to get the impression YOU want, you have to set controls manually, no 'automatism' can do that for you. (for good reasons, the 'camera-man' in a movie production is called 'Director of Photography'!)

and DVDs is for grand-parents only, they're happy with SDef.
for HDef delivery, I use an usb-stick, connected to some MediaPlayer, as a PS3, a Western Digital HD Live, etc.

a 60p playback of blended 30p recordings .. .that would be best of both worlds .. :)

THE DeInterlacer:


JES Deinterlacer .. all deinterlacings on this site were done with this FREE (!) tool. for me unknown reasons, the built-in deinterlacer in iM simply doesn't work. Choose the apple-intermediate on export of the project and let JESDI do its job.

Forget time-consuming deinterlacing, when you re-size your video on export anyhow..

TWO EXAMPLES:


A recording with short shutter-speed (somewhat 1/8.000 , a sunny day):

short shutter speed


A recording with long shutter-speed (near 1/25th, using a NG-filter) :

long shutter speed


both videos are recorded 720 progressive, one looks 'artifically' sharp, the other has the more common 'Film Look' with tons of motion blurr ..


LAST WORD:

Watch videos in its 'native' resolution, NOT 'fullscreen' to judge pic-quality!