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HD not smooth

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Tom Galli
HD not smooth
on May 11, 2013 at 5:40:46 am

Aloha all!

I'm shooting on JVC GY-HM700 and 750 cameras, which were designed in conjunction with Apple and shoot native QuickTime files. I'm recording 1920x1080/60i.

My editing system is FCP 6.x (aka Studio 2). I have numerous different computers, being supervisor of a Mac lab at work. A couple of them have Matrox MXO2 outputs driving JVC DT-V17G1Z monitors.

And I am a Taurus. ;)

So, there are two things.

First and most annoying, my HD footage, after passing thru FCP, doesn't play back smoothly. I have a hard time describing the artifact, though. It's not jerky, nor is it blurry or pixelated. But in movement, there's an effect almost like a soft-edged strobe. It's almost as if the frame rate were reduced, but a dissolve placed between the frames.

At first, I assumed that the artifact wasn't "really" there, but was being introduced by the playback, so I exported some Quicktime files. Nope, it's really there.

I've tried changing the settings of the Quicktime files when I export, using a few different codecs, including the fearsome ProRes 422 HQ. Other than giving me a ridiculously large file, nothing changed.

I've tried changing Sequence Settings, using different codecs, different choices for field priority. Still doesn't help.

Why can't I get the same fantastic-looking, liquid-smooth HD out of my editing system that I am putting into it?

The second thing is, renders take an astoundingly long time! I mean, honestly, to render a 1-second cross dissolve using a 2.89 GHz quad-core Mac Pro with 16 GB RAM is taking 3-4 minutes!

Any help will be greatly appreciated. I'm thinking there are things I have yet to learn about transitioning to HD!

Mahalo,
Tom G

The difference between theory and reality is that, in theory, there is no difference between theory and reality.


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Don Greening
Re: HD not smooth
on May 11, 2013 at 11:14:03 pm

The very first thing I would do is trash FCP's preference files. You can get a free program to do this for you at: http://www.digitalrebellion.com/prefman/

The next thing I would try is to do some system maintenance on that computer, especially if it's never been done before. If your machine is acting very slow then there's probably a ton of old cache files etc. that are plugging up your system. The one I use is here: http://www.macupdate.com/app/mac/11582/onyx

It's also a freebie and there's different versions depending on which version of OS X you're using. System maintenance should be done on a regular basis, more frequently the more you use your machine. The Mac OS is basically a shell program to interface with the basic OS which is UNIX. UNIX was originally developed to run 24/7 and it has scheduled a maintenance program that is supposed to run in the middle of the night when there is minimal use by a user. The trouble is, most people shut their machines off at night so the UNIX maintenance program never gets a chance to run. Hence the need for 3rd party software such as Onyx and others.

Normally one doesn't have to go to such great lengths within FCP to get decent output quality, so it must be something else. Your issue could also be because of corrupt render files, depending on how old your project is and how many times you've re-rendered. Use Media Manager within FCP to delete all your old render files and start again from scratch.

That's all I can think of for now until you can give more information about your system.

- Don

Don Greening
A Vancouver Video Production Company
Reeltime Videoworks
http://www.reeltimevideoworks.com


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Tom Galli
Re: HD not smooth
on May 12, 2013 at 1:04:13 am

Aloha Don,

I think you're barking up the wrong tree here, although I will give trashing preferences a try. It's been a while since I did that.

I keep the computers here well-maintained. They run 5 days a week, get shut down for weekends, and I use MacHelpMate on them monthly to repair preferences and run the UNIX housekeeping chores.

I have moved this project across several systems. The oldest is a white Intel iMac 5.1, the most powerful is the Mac Pro I mentioned, the newest is a 2.3 GHz Mac Mini, and there are several in-between. I've done tests now on 4 different computers, each a different hardware configuration. The OS involved runs from 10.6 - 10.8, depending on the system.

With such a consistent problem across such a range of hardware and OS combinations, I'm pretty certain the issue is internal to FCP. I just don't know what it is, yet.

I'm leaning towards it being some form of interlace issue, though. In the project, I have some still images of assorted formats (.tiff, .jpg, .psd, etc). I use keyframing to apply motion. SOme of them develop jagged edges. That, I can correct by setting the Sequence Settings Field Preference to "none." However, it seems to me that the artidct I'm complaining about is slightly worse after re-rendering the sequence following that change.

The difference between theory and reality is that, in theory, there is no difference between theory and reality.


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Don Greening
Re: HD not smooth
on May 12, 2013 at 1:47:27 am

Okay well I'll ask some basic format questions, now that I know you're practicing preventive maintenance on your machine.

- remember that interlaced HD has a field order of upper first, and interlaced SD is lower first. Make sure your field order is correct for what you're editing.

- Have you tried to play back any other type of camera footage that's not JVC? Specifically, do you have anything progressive you can try?

- You should even be able to output ProRes 422 Proxy and still get an acceptable result, let alone ProRes HQ which, as you know is way overkill for a codec that is Long GOP 4:2:0 to begin with.

- Has your FCP always had this issue or has it happened only recently? if it's the latter then can you think back to when this started and what, if anything, has changed in workflow?

- if you bring in footage that's clean and output the same untouched footage does the quality stay the same or does it go south?

- Have you tried transcoding the original footage to ProRes using Compressor and using the transcoded footage instead of the original? ProRes is a lot easier on the processors and GUI than the original Long GOP stuff. And your render times will be reduced too.

- Don

Don Greening
A Vancouver Video Production Company
Reeltime Videoworks
http://www.reeltimevideoworks.com


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Tom Galli
Re: HD not smooth
on May 13, 2013 at 8:28:06 pm

Aloha Don,

First, thanks for your continued efforts!

1. When I start editing, the system defaults to NTSC DV settings. When i drag the first clip onto the Timeline, FCP offers to change my settings, which I allow it to do. What it chooses is:


Again, I've changes most of the sequences to a Field Dominance of "none" because it smooths jaggies that appear when keyframing still images.

2. Coincidentally, this particular project includes some HDV footage and some SD NTSC analog footage. Nothing progressive, though. My JVC cams do have the capability to shoot progressive, so I can put that on the list of things to try.

3. Yeah, changing the output codec is having little effect.

4. This is brand new. However, let me qualify that, this is also the first paying project I've cut using all HD. I've done a few training projects, and graded dozens of projects from my students using this same equipment, but it is really distinctly possible that I'm only noticing the artifact now because A> I am screening this one for paying clients, and B> if I noticed it in a student project, I would comment on it but not really THINK about it, assuming student error.

5. Simply playing the footage immediately after import, the artifact is present. Even in the Viewer window, now that I am looking for it, I can see it.

6. Nope. I'll stick that on the "to do" list as well!

Mahalo,
Tom G

The difference between theory and reality is that, in theory, there is no difference between theory and reality.


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Don Greening
Re: HD not smooth
on May 14, 2013 at 6:34:57 am

1. FCP is changing to the correct sequence settings when you drop a clip into it. JVC uses the same MPEG2 codec that Sony uses, and that's because Sony actually licenses the XDCAM EX codec to JVC.

2. if you're also utilizing DV NTSC footage in the same HD timeline as everything else then it's going to look awfully pixillated and blurry I would think. Editing Long GOP MPEG2 footage natively is really processor intensive. I'm an XDCAM user as well and i always transcode to ProRes before any editing is done for that very reason.

Another option is to let FCP change the sequence settings to match the footage as per usual but once your first clip is dropped in try changing the compressor setting (in the sequence setting dialogue box you've provided in the picture) to one of the flavours of Pro Res. Then when you render anything it will always be a Pro Res render file.

You can also choose to stay with the XDCAM timeline but set the render codec to be Pro Res. That setting can be found in the Final Cut Pro menu > User Preferences > render control. Using Pro Res for rendering means FCP doesn't have to "conform" any edit point which takes forever it seems.

4. You can also try trashing the Quicktime Player preference file because FCP is basically using QT as its playback engine. See if that makes a difference. Even with my older 1st gen Mac Pro 4 core I never saw anything weird like you're describing the odd time I edited native XDCAM footage.

6. I highly recommend you drop a few seconds of JVC footage into a Pro Res HD timeline, render, then play it back and see if the weirdness goes away. If it does, then there's obviously something about your system that doesn't like MPEG2 video. If you play back some NTSC footage in its proper DV NTSC timeline with lower field first do you still get the weirdness?

Depending on what the final product will be used for will determine whether or not you're recording interlaced or progressive. If used for the web then shooting 24p or 30p is a must. Consumer LCD displays handle interlaced much better than they used to, so there are times when that's preferable, especially for fast action and sports because 60i has smoother playback because of higher temporal resolution.

Let me know how you're getting on.

Cheers,

- Don

Don Greening
A Vancouver Video Production Company
Reeltime Videoworks
http://www.reeltimevideoworks.com


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