Must Accept Stutters??? Does this happen to you? Try this simple test…

[John Fishback]

So many things can cause stuttering. What’s your frame rate? 24fps will often stutter on vertical edges. The American Cinematographer Manual has a table of pan speeds above which you will see stuttering. If you haven’t tried encoding in Compressor with Frame Controls on and appropriate settings at best, try that.

John

MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.8 QT7.6.4 Kona 3 Dual Cinema 23 ATI Radeon HD 3870, 24″ TV-Logic Monitor, ATTO ExpressSAS R380 RAID Adapter, PDE enclosure with 8-drive 6TB RAID 5
FCS 3 (FCP 7.0.2, Motion 4.0.2, Comp 3.5.2, DVDSP 4.2.2, Color 1.5.2)

Pro Tools HD w SYNC IO & 192 Digital I/O, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN

[Ralph Chaney]

This is a real mystery.

Frame rate is 29.97, rendering is at 100%.

The thing is… this problem occurs without even involving Compressor, or Video sources, or anything beyond a simple timeline, elements generated by FCP, and exporting as a Self-contained movie. It’s FCP at it’s simplest, most stripped-down..

How about giving this a look? Maybe try it yourself. Here is a simple project you can open to see how it functions. I’ve tried it on other systems nearby and we all get the same stutter problem. At least 1 out of 4 replays, we see the stutters.

Here is a download, 17 MB that has:
Simple FCP project;
Exported clips, in ProRes and DV;
Screenshots of my settings, for ProRes and DV.

https://rcpt.yousendit.com/868541957/6eb3a12586741a61d79b364c72715c5a

Thank.

-Ralph

-> Ralph

[Matt Lyon]

Ralph,

The problems you are describing are such a moving target. Even if we all watch the same file, there is no guarantee that everyone will see the same motion artifacts. These things are caused by the interaction between graphics cards, specific physical properties of the display, and then all the different software issues and hard drive speed factors.

Not to mention the problems of language. What you call “stuttering” I may call something else. If the issue you are describing is what I think it is, I would call it “tearing.”

The reality of playing back video on a computer display is that you /may/ always get motion artifacts if the refresh rate of the display is not an even multiple of the frame rate of the video. This was easier to combat when everyone used CRTs, since you had more flexibility in changing the refresh rate of the display (for example, using 95.9 hz when playing back 23.976 fps video). Chances are you are watching your 29.97 quicktimes on LCD with fixed refresh rates of 60 hz. And I’m sure there are many other factors, like the response time of the display and the quality of the buffer on the graphics card. I’m not an engineer, so I won’t speculate any more 🙂

But the solution was and will continue to be: when quality matters, monitor video on video monitors, not on computer displays!

Matt Lyon
Editor
Toronto

[Jeremy Doyle]

If it’s only going to be displayed on a computer monitor you’ll want to de-interlace for play back. For what its worth your files are interlaced and optimized for broadcast monitor playback.

Matt explained the science behind it already.

[Ralph Chaney]

Thanks to both of you.

Jeremy, yes, the plan is to go with progressive h.264 for the HD files on the disk. Yes, progressive is a must.

Matt, thanks for bringing up display refresh rate versus video frame rate. It must be something all of us run into if we want people to see our HD footage easily (without jumps). Not very many of our viewers have the gear to see HD on monitors so, practically speaking, we’re left with whatever monitors (and graphics cards, etc.) can provide.

Do you know what the bigger producers do, to get around this problem? When I watch feature film dvd’s on my computer I don’t not get the “stutter” artifact we see in the sample. Apparently it CAN be done. It would be good to know how to do it, for all of us.

Who do you think would know this kind of thing?

If you look at one of the output files you will see the actual artifact and know if it’s “tearing” or “jumps” or what. I’d like to know what you think.

-> Ralph

[Stuart Simpson]

Have you tried using a different encoder? Maybe Episode?

https://www.telestream.net/episode/overview.htm

-Stuart
7 MacPros – Kona 3, Kona LH & Kona LHi
1 G5 – Kona LH
xbox360, Wii, PSP, PS3
https://www.speak.co.uk

[Ralph Chaney]

I’ll give it a try, Stuart. I know someone who’s got Episode.

The things is, the stutter occurs with a simple Export Movie within Final Cut, to a self-contained movie. Could Episode become the engine that FCP uses to create these files and possibly do a better job?

Stuart, I would be very curious to know if you get these same results – I wouldn’t be surprised.
Use the project I have linked to above or create your own simple project. Create a moving rectangle, cross or whatever, out of mattes generated with FCP, and export to a self-contained movie. Then replay it 6 times. I think this might be a universal problem.

It would be good to know if others on this forum get the same results.

Thanks,
R

-> Ralph

[Matt Lyon]

I have watched the sample files and I do see several problems. The main one is the interlacing artifacts. I also see tearing and the occasional (what appears to be) skipped frame (ie, a break in the smoothness of the motion).

But bear in mind that these tests do not represent real world situations. They are designed to show these problems in the most obvious and worst light. I would wager that these problems are more prevalent then you think. They are just much harder to spot in footage shot in real world situations. (Imagine trying to pick out tearing artifacts while being bombarded by the Clash Of The Titans 3D trailer).

I for one DO see problems when playing back DVDs on my laptop — one of the reasons I hate watching DVDs on a computer.

I can’t really speculate on what “big producers do to get around the problem.” My suspicion is nothing. It’s kind of like saying “what do big producers do about the fact the most television sets are horribly calibrated?” There’s nothing they can do 🙂

All this isn’t to say that there aren’t steps one can take to minimize these problems. Maybe there are different software players that do a better job with motion? You could try to get in touch with an engineer at a company like Iridas; they might let you pick their brain on dealing with these sorts of issues.

Matt Lyon
Editor
Toronto

[Ralph Chaney]

Matt,

Yes, with most motion it is hard to pick out, yet it is there. Once you get the knack of seeing it it’s sen all over the place. The problem arises when a particular shot shows it off very well. I suppose like other things that impact editing, it would be time to change the shot or the treatment of it.

I will check this out some more and see what can be done. I checked a few commercial DVD’s and they seemed to play without the stutters. We’ll se what I find out.

I’ll post here if I find something.

Thanks,
Ralph

-> Ralph