Can you convert 60i wrapped 24p to 30p without problems?

C

CRFilms

Active member
I'm about to start a video project that's going to be youtube based and after some initial testing it seems 30p will be the easiest way to go. We may be shooting with 3 different cameras, an iphone, a sony nex, and my gh17. I'm not sure which nex, so for now it seems just taking the 60i and turning it into 30p will be the easiest because I want to transcode the footage into stock MainConcept HDV 720p format(one of the stock presets in Vegas Studio). That stock preset edits fast and previews in realtime on even slow systems. That's also a key consideration, my system can't edit 1080p quickly.

I tried turning 24p into 30p and it didn't look right. I don't want to record in 720p, so I'm going to rehack to one of the 60i wrapped settings. Will turning 60i wrapped 24p to 30p cause any frame/ stuttering/ or other image issues?
 
I'm thinking with 24p to 30p you're adding frames while 60i to 30p, you're just blending the interlaced fields. Even though the 24p is buried in there, the 60i is there also. I've done some tests now and the 60i footage looks better than the 24p footage. 24fps converted to 30p had ghosting while the 60i converted looked fine.
 
I thought the GH1 (and GH17?) offered 30P wrapped as 60i? If so that would be the mode to shoot in - stay away from wrapped 24P for the reason given above.
 
CRFilms said:
I'm thinking with 24p to 30p you're adding frames
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Yes, and there are 3 methods, either inserting duplicate, a blend , or resampling with motion interpolated frames. The key point is, these are not real frames. 24 is less than 30, and you cannot get extra frames for nothing.

while 60i to 30p, you're just blending the interlaced fields. Even though the 24p is buried in there, the 60i is there also. I've done some tests now and the 60i footage looks better than the 24p footage. 24fps converted to 30p had ghosting while the 60i converted looked fine.
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Not necessarily. You can use other methods of deinterlacing. You chose blend deinterlacing (which is probably the worst for most types of projects)

Similarly, your 24p to 30p conversion probably had the same settings on (blend). With frame blend off, instead of ghosting you would get jerks with dupe frames. And the 3rd method will be the smoothest with motion interploated frames, but can have morphing artifacts . The names will depend on which software you are using, but they are basically the same for all NLE's . Some NLE's won't offer the 3rd method

60i => 30p is the "cleaner" because every frame is derived from a real frame. There is no jerking or blending (unless you blend deinterlace). The quality of deinterlacing varies immensely. It ranges from awful to good.
 
I said blend as a general term, I do "interpolate" for the actual de-interlace settings not "blend fields".
 
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