30p, 24p, 60i oh my!

[ntbone]

One thing I was struggling with for a bit, was why 60i would be smoother then 30p. For each of these modes, you have 30 full frames of video per second. I recorded a clip in all 3 modes (60i, PF30 and PF24) in attempts to understand the clips, as well as figure out how to get the footage into EDIUS, the software I use for editing.

I shot all the clips in Tv mode at 1/60th of a second on a Canon HG21.

60i does have that very smooth look to it that is different from PF30 so there must be something different. So "Why does 60i look smoother then 30p?"

60i actually is shooting 60 frames a second at half the vertical resolution. PF30 (30p) is shooting 30 full frames a second. PF24 (24p) is only shoooting 24 full frames a second.

On my camera, as well as many others, each all of these videos are encoded into a 60i stream. For 60i, nothing needs to be done. For PF30, each frame is simply divided into two (odd /even fields, whatever). For PF24, the telecine process is applied.

To reverse the effects on the clip the following needs to be done

60i - nothing. There is no real reversal here. You can apply de-interlacing algorithms that would either give you 30p and do averaging/blending or you could also get 60p, but again you would be interpolating/averaging.

30p - simply separate the fields back out to get progressive content

24p - you must actually apply inverse telecine processing.

I was able to get all apply these processes in AviSynth but have not yet figured out a good way to apply them to EDIUS.

In general, you want to shoot your video such that the shutter speed is 2x or more then the frame rate of the video. This is part of what gives video that "film" look. There is a good video/article out there that explains why this is necessary but I cannot locate it. I will update this post when I find it.

This means for
60i you should shoot 1/120th or faster, though it really doesn't matter since 60i is going to give far smoother motion and likely prevent the film look
30p should shoot 1/60th or faster
24p should shoot 1/48th or faster

[ntbone]

Here is a link explaining why you want 2x the frame rate for that "movie look"

http://www.youtube.com/watch?v=oxXGkbG9KMc

[dean1979]

I have just read a bunch of thes posts about 24p 30p and 60i and generally get the idea that 24p does a film like and 30p is a standard good one that will also work on web.

My questions are im in london and have just purchased a Legria version of the camera (PAL Version) so I wont have 24p so 25p must be what I get and will do the same job?

Second question is can I switch between settings on the same tape or once you have shot in a setting with that tape do you have to stick wity it and if not when bringing into final cut you will have to remember you settings each time then?

Would you suggest just sticking on 30p and be done and that way it wont have pull down (Lines as I understand it) or will it still have pull down?

[Janke]

For the "film look", use 25p. It will look the same.

You can't do 24p or 30p with a PAL camcorder (you can with DSLRs, though), but you can shoot "smooth, video-like" 50i with it, to be shown on TV from the camera or a DVD.

For the web, use only 25p, 50i can cause interlace lines.

[dean1979]

Hey Janke

What would you say would be the best to use to bring into final cut without pulldown and also for general good quality to keep for future?

[Janke]

25p or 50i in PAL

30p or 60i on NTSC

No pulldown needed for any of these, just the right timeline setting, exactly matching what you shot.

[dean1979]

PS can you use different settings on the same tape? EG can I shoot 20 mins of footage on one subject for web then another 20 mins of footage on that tape for broadcast?

Also will I need to then change my bringing in settings on FCP for those separate parts of footage on that same tape?

Or is this not the done thing?

[Janke]

Both 25 and 50 work for broadcast, 25 is better for web, but you can deinterlace 50i for web use.

I shoot 50i on my HV30 and 25p on my 550D - and mix them at will, in the same timeline.

Here you can see what happens with p and i on YouTube - stop the video and note the double balls in almost all interlaced footage:

[dean1979]

Right so the answer is...
1. 25 for web
2. 50 for tv

But you can just deinterlace 50 in FCP and use it for web, so 50 is the best all round to archive footage and just deinterlace if and when you want it for web.

To deinterlace all I have to do is drag the deinterlace filter from the video folder in FCP right?

[Janke]

50 is the best all round

Slightly less vertical resolution when deinterlaced.

To deinterlace all I have to do is drag the deinterlace filter from the video folder in FCP right?

Correct.

[dean1979]

Im going to shoot 50.

Just for interest can you mix footage settings on the same tape? 20 mins 30p and then 20 mins 50i? If so would you have to change your settings in FCP for bringing in separately or can you just stay on same setting.

[Janke]

You can't shoot 30p and 50i with the same HVXX PAL camera.

25p and 50i - yes, they can be on the same tape. Mixing may cause some glitches during transfer to FCP, though.

[dean1979]

Sorry 25p and 50i is what I meant. Still very new so get it back to front sometimes.

So best idea is choose one and stick to it for at least that tape.
Prob 50i as its best all round.

But the 25p is the one with more the film look is it?
Thank you for the info.

[cgbier]

If you know where exactly the cut is between 25p and 50i, you can shoot both on one tape. You'll just have to change the Easy Setup in between. Only do it if you either have a shooting log, or capture your tape right when you come home. You might have forgotten about the cut after some days/weeks/months/years...

[robisaistru]

I shoot a lot of live music with multiple cameras, most of it hard rock. From my point of view for shooting music 24p and 30p aren't good. Anything with fast movement is going to have that near strobed look, drumsticks especially. 60i snaps the frames at 60 times a second, their half the resolution of 30p for example, but twice the temporal resolution (the pictures are taken faster) so motion isn't nearly so much problem. I always shoot with either 60i or 60p. Some shows are fine at 24p and 30p.

This seems like a good place to ask, i read through most of the posts and have been looking through different forums for help.

I've been shooting multicam for awhile with anything from hv20/30 to trv22, to gs320 (pan) to gh1, hvx200 and others. Just recently i got more HD cams. They're card based (so they're avchd).

To edit, i always make an SD timeline (720x480) and import all of the footage. At first i stuck with SD timeline because most cams were SD, and i liked being able to pan/scan the HD frames to make them framed better. But now, most of the cameras are HD and i'm not sure if i'm rendering right.

I still use SD cameras, they're lower field first, but the HD cams are upper. The question, when i have multiple footage, all with different frame rates and field orders, on the same timeline, do i need to do anything to make sure they're all exported correctly? I always export as standard mpg2, nothing fancy, always SD, and always lower field first.

I've *been* doing it this way and everything seems/looks fine, but i started to wonder if maybe what i'm doing is loosing detail. It didn't matter a lot since it was a mix of SD and HD cams, in fact it wouldn't hurt to loose a little detail so the cameras come closer to matching (though there are better ways to make them). Since most cameras are HD now i need to be sure..

So, say i have footage from the hv30 (upper field first) and footage from a trv900 (a dvcam so lower field first). I make a timeline in premiere of type SD 72x480 lower field first. When i imort the hv30 footage, since the timeline in lower field first, do i need to reverse field order to make sure the trv900 and the hv30 have the same field order, or does premiere figure it out? I'm guessing that if the field orders are mismatched, the mpg2 files can cause problems with some equipment. Some of these files might be broadcast later so i was hoping to be sure there won't be problems later.

[Playing]

This is definitely a minefield. I tried to render HD 50i to an SD 50i DVD and both pan/scan and slow motion caused havoc. De-interlacing to SD 25p was OK.

[robisaistru]

DVD is top field first so the rendering order would be reversed, but still the same issue since it's a matter of making sure the field orders are consistent. Or rather it's a question of, is it important that the field orders for each source clip on a timeline are the same before they get rendered? And if so, does reversing field order for clips that are different field order than the project type you're editing in solve the problem? I think the obvious reply would be try it and see. I've rendered hundreds of videos, mostly all BFF, but most recent ones are mixed BFF and TFF and have been meant for web only, so any problems aren't visible as far as i can tell. But some videos may be on broadcast or DVD and i don't know how to tell if mixing field order could cause problems later (as in with the broadcast station's equipment) or with dvd.

[Janke]

Usually the software should take care of field order. On m Mac, I've never had a problem converting HD to SD.

[robisaistru]

So multiple formats on the same timeline aren't a problem i'm assuming. i.e. a mixture of standard DV (bottom field first) with AVCHD and HDV (TFF). I'm guessing that the editor (premiere cs5 in my case) figures out field order for a clip when it imports and interprets it the way it needs to, even though the project is set to one field order or the other when it's first made. I haven't seen any problems, but then like i was saying, i've been editing mostly SD up until recently.

[cgbier]

Like Janke said, you define the whole project's field order on output. Your software is supposed to take care of it.
I've been mixing SD/HDV/stills without any issue.

[tobyread]

how do i find these additional 25p, 50i and so on settings on my HV40, when i go into my dropdown menu all i get is HDV, HDV(PF25), DV and DV (normal) i know this is elementary for you guys but the help will be very appreciated.

[Janke]

PF25 is 25p, everything else is 50i.

[tobyread]

thanks mate, so surf videography il shoot in TV mode on PF25! sound good

[tobyread]

and how do i get 30p,24p and 60i as listed above on my hv40

[cgbier]

By buying an NTSC model.