twitchy dvds

Posted by fran benton 
twitchy dvds
April 09, 2007 11:22PM
Hi Guys,
I took everyone's great advice and did a big upgrade to my system. I just have to thank all you experts out there who guided me to some really sound decisions. I now have final cut 4 and tiger and toast8 to burn my dvds. I am just dumping the last project off final cut 3 before I move over to fcp4. My problem is that my newly burnt DVDs look fantastic on the pc oe the mac. When I play them on the Toshiba DVD player they have a twitch every other second. I tried to drop the burn speed on Toast from best to X1 and then X1DVD. The twitch remains. I have 3 different types of DVD so I tried them all but the twitch is still there. I'v gone through the forum to try to find another problem like this and I'm stumped. Can you tell me the best settings to use on Toast 8 going from 30 to 45 minute projects on fcp?
Re: twitchy dvds
April 10, 2007 12:16AM
what format are the original clips that the DVD's are created from? PAL or NTSC? mov or avi? DV or other? just fishing here
Re: twitchy dvds
April 10, 2007 01:44AM
By the way, the stand-alone DVD player into the glass TV is correct. The DVD really looks like that.

The computers have to subsample and supersample the video playback to force a matchup with their screen scan rates and they tend to hide problems like that. This is also why we suggest--strongly--that you keep a glass monitor connected to your machine while you're editing to catch problems like this before the phone calls start.

I'm with Mees. You did a standards or scan conversion somewhere you shouldn't have.

Re: twitchy dvds
April 10, 2007 01:13PM
The clips are .mov I saved the final cut project through export as a final cut pro movie. And the clips are NTSC. So a standards or scan conversion. I'm sorry I'm not sure what that is. Would that have happened when I upgraded or is this something I would have done in final cut pro?
Re: twitchy dvds
April 11, 2007 03:05AM
hmm.. when you export as FCP movie, are there any options or settings you can choose/set, and if so what options or settings did you choose/set? and what are the defaults?

it sounds like either your field order is somehow reversed in your .mov exports, or Toast 8 has misintertpreted the field order when building the mpeg2 files for the DVD
Re: twitchy dvds
April 12, 2007 10:55AM
Thanks for your response Andy, I am away from my machine so I can't get the settings. (I work in a different town than the one I live in) I will check all the settings you advised and see what effect changing them will make. Thanks for your help,
Re: twitchy dvds
April 14, 2007 12:31PM
Here is a similar problem I am able to reproduce on ANY Mac running current versions of software and the solution I have. I am shocked this doesnt come up more often on the boards.

Take an Uncompressed QT movie, made from a FCP Sequence. The footage is interlaced (the problem doesnt show on progressive footage like 30p). Throw it into iDVD 6. Make the DVD. It will show all kinds of awful twitters in the motion areas. Unwatchable. This is entirely reproducible on any system with current versions of QT and iDVD 6.

The solution: Using the Settings box in QT Pro (use Command-J to get there), convert the size of your uncompressed movie from 720x486 to 640x486. Make sure you have "Preserve Aspect Ratio" UN-checked. Now save. It now makes BEAUTIFUL interlace DVDs.

Try this and see if it also works for Toast.

- Christopher S. Johnson
Re: twitchy dvds
April 17, 2007 12:36AM
I've been experiencing a similar problem.

I'm putting together a DVD compiled of footage from different sources. I'm using various sections from one DV-compression clip as different chapters in the DVD. Parts of that footage consistently twitch (active and less active), although not all, and footage from other sources doesn't.

In FCP 5.0.4, I did some settings changes to optimise the titles I made, but then the twitching caused me to pursue different tests to resolve it.

I've tried changing the sequence settings to Animation Codec (or just leaving it at DV/DVCPRO copmression), render (or not) and then Export Quicktime Movie. From there, to Compressor to get the MPEG2 Best, 2-pass VBR treatment, 2 days later (more or less) onwards to DSP for building/muxxing to a .img file (or straight to DVD.) I even tried using DSP's asset encoder (hiss) to see if that was the problem. The clips that twitch, twitch.

I played back the files (the Animation codec'd ones, the m2v's) back in Quicktime and in DSP's simulator. If you know what/where to look for twitchiness, you can actually almost see that something unnaturaly is going on even on the computer screen. But that's with foresight, and useful for troubleshooting- not so much for trouble-spotting (i.e. before trying to figure out where you went wrong.) But really, Koz speaks wisdom- having a TV attached would most likely have brought the crisis to light much earlier in the workflow. And when dealing with Compressor on my 1GHz Powerbook, that's no small thing!

So here's what I did:
Since i basically had one layer of video, it was easy enough to duplicate it to another (adjacent) video track. Put the De-Interlace filter on both, and set one to Upper, the other to Lower, then I set the opacity to something like 85 or 90- so the change was insignificant for the purpose of the project- I learned about doing this from LAFCPUG, as part of a process for getting a 'film look' out of DV footage. Sequence Settings to Animation, Field Dominance:None, and so on- Cadillac! Problem dodged.

But this was more of a workaround- to meet a deadline. Fundamentally, there seems to be a discrepancy somewhere... with field dominance or something. I have to look into it when I get a moment and a TV.
Re: twitchy dvds
April 17, 2007 11:41AM
So if I understand correctly, you made the video progressive with your trick. That's what I was saying before: 30p footage didnt have the bad effect.

Someone with the problem in interlace footage, try my method above (making the QT Movie 640x480 or 486, save it, and then see how it behaves in iDVD or whatever.

My experience is that it fixes the weird field jumping and keeps things with the original intended interlace look.


Re: twitchy dvds
April 19, 2007 02:14PM
Effectively, yes, it makes the video progressive.

But help me understand something about your method: does it resizes the video? Is the resulting video different in any other way (cropped? stretched?) I'm going to try this when I get back to my videos.

Re: twitchy dvds
April 19, 2007 02:20PM
Yes, it is slightly resized, but it pops back into proper aspect in iDVD. I have no earthly idea why this works. Its magic. But I do know that the results look very good, the video that was intended to be interlace stays that way, and everything is fixed when I do that.

I wish I had a logical reason this works.

-Christopher S. Johnson
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