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Old May 30th, 2011, 03:21 PM   #1
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Blur/motion/ghosting lines on video? How to fix

So, in this video below I noticed there were these ghosting/motion lines around certain subjects in a shot. The best instnace here is of the girl in the second to last clip in the footage.

These were rendered for the Internet HD setting in Vegas.

Any idea how these things got there and how to get rid of them?

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Old May 30th, 2011, 03:33 PM   #2
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Re: Blur/motion/ghosting lines on video? How to fix

Those are resampled frames. Looks like you might have rendered out to a different frame rate from the underlying footage -- maybe 24p to 30p?

You can try to go into the clip properties and check "Disable Resample," but for some frame rate conversions -- like 24p to 30p or vice-versa -- the rates are just too close for an artifact-free conversion, so you still may see some of the ghosting.

If it's 60p to 30p, or 60p to 24p, or vice-versa on either, then it *should* set you right.
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Old May 30th, 2011, 05:31 PM   #3
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Re: Blur/motion/ghosting lines on video? How to fix

Quote:
Originally Posted by David Jimerson View Post
Those are resampled frames. Looks like you might have rendered out to a different frame rate from the underlying footage -- maybe 24p to 30p?

You can try to go into the clip properties and check "Disable Resample," but for some frame rate conversions -- like 24p to 30p or vice-versa -- the rates are just too close for an artifact-free conversion, so you still may see some of the ghosting.

If it's 60p to 30p, or 60p to 24p, or vice-versa on either, then it *should* set you right.
Yes, I think this is exactly what happened.
I kept trying to render the project at 60 and Vegas kept crashing. Eventually, I just clicked on the pre-set 30p setting and it rendered.

So, the question now is why would Vegas keep crashing at the first settings?

I will go and try your suggestion and see if that clears some of it up.
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Old May 30th, 2011, 05:56 PM   #4
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Re: Blur/motion/ghosting lines on video? How to fix

What's the frame rate of the footage? If it's 24p, render as 23.976.
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Old May 30th, 2011, 06:21 PM   #5
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Re: Blur/motion/ghosting lines on video? How to fix

Humm, unsure how to check the P on the T2i (still learning it).

It was shot at 1920x1080 24fps.
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Old May 30th, 2011, 06:25 PM   #6
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Re: Blur/motion/ghosting lines on video? How to fix

There is no 24 interlaced, so if it's 24 fps, it's 24p.

Cut on an HD 1920x1080 24p timeline, Render as 23.976, progressive.
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Old May 31st, 2011, 03:04 PM   #7
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Re: Blur/motion/ghosting lines on video? How to fix

Thanks, David, I will give that a go and see if it clears that blur up.
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Old June 2nd, 2011, 03:06 PM   #8
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Re: Blur/motion/ghosting lines on video? How to fix

David, finally got around to your suggestions last night. It worked great!
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Here is a follow-up:
If I am shooting at 24fps with th eT2i should I ALWAYS render at 1920x1080 at 24p?
I had read on another forum that I should be using 50i for best quality.
Could 50i be used in combo with 23.976, progressive?

If not, what are the notations of 50i and 60i used for as, I deduce, if I shoot at 1920x1080 30fps I should be using 30p in the timeline as well?
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Old June 2nd, 2011, 03:14 PM   #9
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Re: Blur/motion/ghosting lines on video? How to fix

No. 24p is not directly compatible with 50i. I mean, you can cut them together, but there's going to a compromise and a quality loss somewhere along the line.

If your footage is all 24p, you should always edit on a 24p timeline.

How you *render* is a matter of what you plan to do with the footage, but in almost all cases, 23.976 will be correct, because almost everything you might do with it will accommodate it (web, DVD, etc.). Just about the only time you should render as something else (60i or 60p) will involve either broadcast or going to some form of tape.

If you shoot 30p, you can edit as 30p, or it'll work as easily as 60p or 60i. But 30p is best. Matching your timeline to your footage is a best practice in general.

50i is not really a standard which applies to anything you'd do in North America. That's a standard for Europe and other 50hz countries.
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Old June 2nd, 2011, 05:29 PM   #10
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Re: Blur/motion/ghosting lines on video? How to fix

Quote:
Originally Posted by Robert James View Post
I had read on another forum that I should be using 50i for best quality.
There is no “best” as it all depends on what you are shooting (e.g. fast moving objects often look better in “i”). Even then, that would only apply to shooting. For editing you should stick to whatever fps you used to shoot whenever possible.
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Old June 2nd, 2011, 05:43 PM   #11
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Re: Blur/motion/ghosting lines on video? How to fix

Right; if you're asking about the frame rate for shooting, it's about what you want the footage to look like. Different frame rates have different motion cadences and thus are appropriate for different purposes.

But I'd still say 50i isn't appropriate in North America because you'll have trouble with it on TV sets and with DVD players. 60i or 60p is what you'd want instead. They'll all have that "live" look common to "video."
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Old June 2nd, 2011, 05:47 PM   #12
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Re: Blur/motion/ghosting lines on video? How to fix

Okay, I think I get it.

That said, the Canon t2i seems to have these shooting sizes (I don't think I will be shooting in PAL so I will omit those):
1920x1080 (30 fps)
1920x1080 (24 fps)
1280x720 (60 fps)
640 x 480 (60 fps)
and CROP

I guess where I am confused is where the whole 50i / 60i came in as I don't see that anywhere.

From what I am reading here the Frames Per Second (FPS) also means (p as in 24p = 24fps). If not, does P mean PROGRESSIVE and i INTERLACED and how does that all relate to the shooting modes above (mainly 1920x108-0 24fps which, I think, is where I will be staying almost always for a more cinimatic look)?

I have read to avoid interlaced and always go with progressive scan which is what I have been doing.

Those, when taken into a Vegas timeline the settings there should reflect what it was shot at. I had always been selecting 50i and altering the FPS as I had read I should be doing so on another site.

That seems like a mistake now, if I am reading you guys right.

All those choices in Vegas can get pretty confusing for a NEWB. :p
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Old June 2nd, 2011, 06:12 PM   #13
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Re: Blur/motion/ghosting lines on video? How to fix

All of those frame rates are progressive. (720 is always progressive.)

50i is a PAL standard. You just don't need to worry about it unless you're planning to deliver something in a PAL country.

These days, with the cameras available, there's very little reason to shoot interlaced unless you want 1080 at 60 hz (60i) or 480 at 60 hz (60i), because for the most part, cameras don't do 60p in 1080 or 480, only 60i. And if you want 60 hz, it'll be because you want the "live" look, and the faster rate gives you 60 pictures or motion samples per second. The motion of 60i is identical to 60p.

Interlaced is always a compromise. It always was. Hopefully before too long it won't even exist as an acquisition format.

24p is, as you say, the cinematic frame rate and the motion is the same as 24 fps film.

30p is something in between. Often you'll see people say it's "best for the web," but there a number of reasons why that's not true. It's best if it's what you want your footage to look like, but it's not "best" in and of itself.

And yes, match your timeline to your footage. I have no idea why anyone would ever say you should cut in a 50i timeline with 24p. That's pretty baffling.
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Old June 3rd, 2011, 09:04 AM   #14
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Re: Blur/motion/ghosting lines on video? How to fix

Quote:
Originally Posted by David Jimerson View Post
All of those frame rates are progressive. (720 is always progressive.)

50i is a PAL standard. You just don't need to worry about it unless you're planning to deliver something in a PAL country.

These days, with the cameras available, there's very little reason to shoot interlaced unless you want 1080 at 60 hz (60i) or 480 at 60 hz (60i), because for the most part, cameras don't do 60p in 1080 or 480, only 60i. And if you want 60 hz, it'll be because you want the "live" look, and the faster rate gives you 60 pictures or motion samples per second. The motion of 60i is identical to 60p.

Interlaced is always a compromise. It always was. Hopefully before too long it won't even exist as an acquisition format.

24p is, as you say, the cinematic frame rate and the motion is the same as 24 fps film.

30p is something in between. Often you'll see people say it's "best for the web," but there a number of reasons why that's not true. It's best if it's what you want your footage to look like, but it's not "best" in and of itself.

And yes, match your timeline to your footage. I have no idea why anyone would ever say you should cut in a 50i timeline with 24p. That's pretty baffling.

David, thanks for all your advice. I realize now that all my previous videos (found scattered about on the forum) were all cut/rendered incorrectly based on the advice I was reading on what I can only assume now was a forum from Europe. I was reading all about 50i and thinking I needed to keep the 24 fps not realizing the p and fps were the same'ish.

I would have gone on forever mucking up my stuff if not for this place which continues to help.

Thanks again.
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Old June 3rd, 2011, 10:01 AM   #15
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Re: Blur/motion/ghosting lines on video? How to fix

The frame rate and p or i are not the same thing. Progressive means full-frame pictures are taken. Interlaced means half-frame pictures are taken, the half being every other line of vertical resolution (line 1, line 3, line 5, etc., then the next picture would be the even-numbered lines).

A few points:

60i is often called "30i" or "29.97i," because the time code is based on 29.97 frames per second, but it's inaccurate, misleading, and confusing. It's a throwback which is no longer necessary.

60i is more properly called "59.94i." This is because there are actually 60 (59.94) pictures taken per second, not 30. Each interlaced field is a separate picture. They say two fields put together make a "frame," but anyone who's worked with video knows why that isn't true -- you'll see the comb artifacts made by mashing together two pictures taken at different times.

This matters to the motion, too, because a moving object is in twice as many positions per second as it would be in true 30 fps. True 30 fps would be 30 pictures per second, meaning there's twice as wide a gap between the positions of moving objects from picture to picture. Obviously, less of a gap means smoother motion, so 60i motion is twice as fluid as 30p.

So, you can see why 60i and 60p would have the same motion -- it's the same number of positions per second for any moving object. 60p being progressive, the resolution of a 60p frame is twice that of any 60i field, but the motion characteristics are exactly the same.

There really is no such thing as 30i or 29.97i -- no format shoots or displays 30 interlaced fields per second. But, you'll still see that nomenclature in legacy equipment and software with a history going back more than a decade. Would be nice if it would go away, because it's confusing.
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