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-   -   50i to 50p software conversion ?! (http://www.dvinfo.net/forum/open-dv-discussion/239433-50i-50p-software-conversion.html)

Marcello Mazzilli July 21st, 2009 01:45 PM

50i to 50p software conversion ?!
 
Hi. Now that people are using LCD monitors and not the old CRT, "interlaced" has changed meaning a little.

This is what was happening before... The "light pencil" inside the tube was drawing the odd lines in 1/50th of a second (PAL) and then (the next 1/50th of second) the even lines. Doing a normal scan from top to bottom, on old TV sets, would have given a nice image at the top and a wobbly image at the bottom (this because the top part would have stayed on screen enough while the bottom part would have been drawn just a fraction of a second before it was to be deleted for the next frame).

Now is different. No LCD monitors simulate the interlaced video in this way. They actually create 50 fps from a 50i footage in different ways, using algorithm. What the LCD TV sets do (and even some Softwares like DVD Player on MAC) is to create 50p (progressive) frames. Something like this. Let's say we have 1 second of interlaced footage. That will be 25 frames with 2 different fields each.That will be 1u,1l,2u,2l,3u,3l,4u.... What the LCD algorythm does is create interpolated full frames. The first one will be (1u+1l)... ("+" means "interpolated with"), the second will be (1l+2U), the third (2U+2L), the fourth (2L+3U), etc... In this way the LCD TV set actually creates 50 DIFFERENT progressive images of decent quality from 50i footage (that is 50 half resolution frames).

Sorry for this long explanation..... My question is... What is the best SOFTWARE for my MAC to convert 1080/50i footage to 1080/50p footage (not 25p... 50p .. .!!!).


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