[starman]

This is something I had in my head to do for a while: take a time lapse movie of a vinyl record, but in such a way where the frames are shot when the vinyl is in the same spot every third rotation.

Sound easy? It's not.

First, I couldn't find a single piece of software that took frames in intervals of a fraction of a second, and worse, that could use my EOS 20D. I have an HD video camera, but iStopMotion wanted me to shell out $460 to use it in HD. Other apps just couldn't work, so after exhausting every resource I had, I did the one thing that I had to do: download the Canon EOS SDK and write the goddamn app myself.

A 33-1/3RPM vinyl is supposed to have .555555r rotations per second (33.3333r/60). That's about 1.8 rotations/second, so every third rotation comes to about every 5.4 seconds.

With drift, a new belt (timed), and delays in the NSController code, I set the NSTimer to 5.5560 and this is the result:

http://geekistry.com/Oxygene.mov

There's drift at the end, and I don't know why. Who cares? It's fun to watch.

[MM-o4]

I'd just use After Effects

[Paco500]

That is so pointlessly cool.

[BadKosh]

Use BTV Pro. you can set up your firewire attached video camera to grab a frame per whatever interval you want. I used it for stop motion animation. I set it for 20 seconds so I had time to move the figures and get out of the frame.

[starman]

Originally Posted by BadKosh 

Use BTV Pro. you can set up your firewire attached video camera to grab a frame per whatever interval you want. I used it for stop motion animation. I set it for 20 seconds so I had time to move the figures and get out of the frame.

I'm using a Canon EOS20D via USB. My HD camcorder is USB also.

Another thing - I had to time this down to the thousandth of a second. I doubt any app out there can do that since I went through all of them.

[alligator]

This is a great idea, and executed really well.

[starman]

Thanks. It was a test, really. I plan on doing a better one (without a bag in the way) next time. I was cleaning while doing that which is why my shadows are all over it.

[wallinbl]

Originally Posted by starman 

Thanks. It was a test, really. I plan on doing a better one (without a bag in the way) next time. I was cleaning while doing that which is why my shadows are all over it.

I was going to mention that, but didn't want to piss on something otherwise cool.

[andi*pandi]

Clever.

is the drift due to the decreased time it takes per revolution closer to the end of the album?

[Spheric Harlot]

Originally Posted by andi*pandi 

Clever.

is the drift due to the decreased time it takes per revolution closer to the end of the album?

You're thinking of CDs.

LPs are constant speed. The *groove* moves slower towards the end, since it has less distance to cover, but the record's rotational speed never changes.

The shift you're seeing is a problem with the turntable. Something's broken.

[RAILhead]

This is one of the most stupid comedies I've ever seen. Can't anyone make good movies any longer?

/zing

[andi*pandi]

Originally Posted by Spheric Harlot 

You're thinking of CDs.

LPs are constant speed. The *groove* moves slower towards the end, since it has less distance to cover, but the record's rotational speed never changes.

The shift you're seeing is a problem with the turntable. Something's broken.

Cool. Learned something today.

[starman]

Originally Posted by Spheric Harlot 

You're thinking of CDs.

LPs are constant speed. The *groove* moves slower towards the end, since it has less distance to cover, but the record's rotational speed never changes.

The shift you're seeing is a problem with the turntable. Something's broken.

Uh, no. It's not broken. If it were "broken", then the record would have drifted all over the place the whole time. I'm thinking it was the weight of the needle at the end of the record that caused it. OR, it could be the TIMING on the Mac that did it. Remember that drift as much as a fraction of a second in the timing on the Mac could skew things. Maybe the Mac is broken. Or maybe the camera's broken.

The turntable's 31 years old, and has held up with constant care since.

[Spheric Harlot]

If your records' rotational speed is slowing towards the end of a record, then something's broken.

Whether it's broken by design, by material failure, or by maladjustment (anti-skating, weight) doesn't affect that what it's doing should not be happening.

OTOH, it could be the Mac's timing as well. Although it's odd that it should be so stable before drifting in a definite direction (rather than randomly).

[starman]

It's impossible to tell for sure. The timing is to FOUR DECIMAL PLACES. It took 45 minutes just to get that and I don't even know if it's right. Also, a lot of other factors could be the problem like power fluctuations in the house. Without marking the belt position and an EXTERNAL source checking when the timing kicked in, your assumption about the turntable being "broken" seems premature.

I just put a new belt on two months ago, and the timing on the belt is fine.

[Spheric Harlot]

Well, something either caused the computer's time lapse to speed up, or the turntable to slow down.

I do know which I consider more likely.

[starman]

Originally Posted by Spheric Harlot 

Well, something either caused the computer's time lapse to speed up, or the turntable to slow down.

I do know which I consider more likely.

Why does this matter to you so much?

[Spheric Harlot]

More often than not, a badly adjusted turntable simply destroys vinyl. I have a couple of such records, and it's just sad to know that they're destroyed just lost.

[starman]

Well you'll be HAPPY to know that I just ran another test and it didn't drift nearly as much this time around.

So....there ya go.

[abbaZaba]

edit: phooey. forget it.