Logic boards for variable framerates? at DVinfo.net

Jim Lafferty · June 15th, 2004, 10:01 AM

Hello all...

I know I'm late to the party on this one -- just throwing this out to the good people on this forum. I'm starting this thread in the hopes that -- as I'm no expert -- someone here is, and will be willing to share ideas. I think the DIY camera projects have competent tech people in spades -- what's lacking is a streamlined conceptual design. Here's some thoughts in that direction --

I'm thinking that I'd like to build a camera that records a video stream (.avi preferred, but .mpeg might suffice as well) to a mini HD. I plan on looking over Obin's work and the work of others in this department. However...

Where other aspects of the project are concerned, I'm most interested in working to create a variable frame-rate cam, ala the kinetta. I don't see why this would be impossible -- it seems to me that an electronica gate should be flexible where timing is concerned, and it should be possible to build a realtime dial that allows the shooter to shift from, say, 4 to 8 to 16 to 24 to 30 progressive frames. Even go higher for slomo effects in camera.

Where should I be looking -- aside from the obvious answer of Google -- for info on aquisition systems (bringing the stream(s) to a hard drive), and more importantly, for info on electronic gates?

Thanks for your help...

- jim

Jim Lafferty · June 15th, 2004, 10:37 AM

I've written something up elsewhere that condenses the kinds of things I'm interested in getting out of the project. Maybe this is useful info:

Imagine if your cam could:

Do variable framerates, in true progressive-scan. After all, we know interlacing is a legacy hack, so why the hell in 2004 do I have to deal with it? Variable framerates should be a given -- electronic gates in a DV camera are just that -- electronic -- and they should be controllable with the right circuitry and code to achieve framerates that fall outside the narrow band of what's deemed acceptable by the industry -- I want 4, 8, 16, 24, 30, 48 and 60fps, for example. I want a button or dial on the outside of my cam that allows me to switch between these on the fly, just like my lowly K-3 allows.

Record your video stream to a hard drive, and later, compact flash. There should be ports on the camera's chassis that accept both of these media types, with standard firewire outputs for hip-worn media drives. Then you could pick up a relatively innexpensive ($500) recording solution and spit out native .avi or .mpeg to the drive, never having to worry about changing tapes, and minimizing production waste in the process.

Leave parts of the camera's feature-set behind if you don't care for them, but also have its circuitry either firm or software based to accomodate a community of open-source hacks and features. Should be possible given something similar to flashable ROM seen in PC equipment. Or, have your cam run a very, very simple layer of software ontop of the hardware that is updatable over the firewire port, or something equally simple. As easy as changing ring tones on your cell phone, you could download custom looks and presets into your cam from the internet and select them from its drop-down menu!

Incorporate a standard Nikon 35mm lens mount Done already!

Obin Olson · June 22nd, 2004, 11:30 AM

right on Jim, sad we are all under the control of the "BIG BOYS" I guess I am changing that but I sure wish I did not have to!! it's a pain in the ass!

June 15th, 2004, 10:01 AM	#1
Jim Lafferty Major Player Join Date: Dec 2003 Location: Brooklyn, NY Posts: 636	Logic boards for variable framerates? Hello all... I know I'm late to the party on this one -- just throwing this out to the good people on this forum. I'm starting this thread in the hopes that -- as I'm no expert -- someone here is, and will be willing to share ideas. I think the DIY camera projects have competent tech people in spades -- what's lacking is a streamlined conceptual design. Here's some thoughts in that direction -- I'm thinking that I'd like to build a camera that records a video stream (.avi preferred, but .mpeg might suffice as well) to a mini HD. I plan on looking over Obin's work and the work of others in this department. However... Where other aspects of the project are concerned, I'm most interested in working to create a variable frame-rate cam, ala the kinetta. I don't see why this would be impossible -- it seems to me that an electronica gate should be flexible where timing is concerned, and it should be possible to build a realtime dial that allows the shooter to shift from, say, 4 to 8 to 16 to 24 to 30 progressive frames. Even go higher for slomo effects in camera. Where should I be looking -- aside from the obvious answer of Google -- for info on aquisition systems (bringing the stream(s) to a hard drive), and more importantly, for info on electronic gates? Thanks for your help... - jim __________________ Realism, anyway, is never exactly the same as reality, and in the cinema it is of necessity faked. -- J-L G

June 15th, 2004, 10:37 AM	#2
Jim Lafferty Major Player Join Date: Dec 2003 Location: Brooklyn, NY Posts: 636	I've written something up elsewhere that condenses the kinds of things I'm interested in getting out of the project. Maybe this is useful info: Imagine if your cam could: Do variable framerates, in true progressive-scan. After all, we know interlacing is a legacy hack, so why the hell in 2004 do I have to deal with it? Variable framerates should be a given -- electronic gates in a DV camera are just that -- electronic -- and they should be controllable with the right circuitry and code to achieve framerates that fall outside the narrow band of what's deemed acceptable by the industry -- I want 4, 8, 16, 24, 30, 48 and 60fps, for example. I want a button or dial on the outside of my cam that allows me to switch between these on the fly, just like my lowly K-3 allows. Record your video stream to a hard drive, and later, compact flash. There should be ports on the camera's chassis that accept both of these media types, with standard firewire outputs for hip-worn media drives. Then you could pick up a relatively innexpensive ($500) recording solution and spit out native .avi or .mpeg to the drive, never having to worry about changing tapes, and minimizing production waste in the process. Leave parts of the camera's feature-set behind if you don't care for them, but also have its circuitry either firm or software based to accomodate a community of open-source hacks and features. Should be possible given something similar to flashable ROM seen in PC equipment. Or, have your cam run a very, very simple layer of software ontop of the hardware that is updatable over the firewire port, or something equally simple. As easy as changing ring tones on your cell phone, you could download custom looks and presets into your cam from the internet and select them from its drop-down menu! Incorporate a standard Nikon 35mm lens mount Done already! __________________ Realism, anyway, is never exactly the same as reality, and in the cinema it is of necessity faked. -- J-L G

June 22nd, 2004, 11:30 AM	#3
Obin Olson Trustee Join Date: Jan 2003 Location: Wilmington NC Posts: 1,414	right on Jim, sad we are all under the control of the "BIG BOYS" I guess I am changing that but I sure wish I did not have to!! it's a pain in the ass!