jit.qt.grab deinterlace

Bullen's icon

Hi,

I have a patch with jit.qt.grab and want to deinterlace the incoming video, which is 1080i
How can I do that??

Cheers

zlp's icon

If you send a "singlefield 1" message to jit.grab you can throw away one fieldset, but that cuts your vertical rez in half.

There's a simple de-interlacer shader included with MAX:
(Cycling 74 folder / jitter-shaders / convolution / cf.deinterlace.jxs)

Or you can try vade's de-interlace shader v001.deinterlace.jxs (attached to this post - seems to be gone from the internet these days?)

I think both shaders do simple field mixing, so they look better than "singlefield 1", but you won't get full sharpness either. You can read about smarter de-interlacing methods on the VLC wiki (none are available in MAX though).

vade-v001-deinterlace-shader.zip
zip
Bullen's icon

Thanks, will try and see how it works out

Cheers

Bullen's icon

Hi,
Tried "If you send a singlefield 1 message to jit.grab you can throw away one fieldset, but of course it lowers your vertical rez." Jit.qt.grab doesn't understand it??

Weird

zlp's icon

Perhaps the new QTKit grabber in 6.1.6 / Mavericks lost the singlefield capability? Or maybe some digitizers don't support it? I've used it many time for DV inputs.

Bullen's icon

Hi,

I just saw in the help file that's it's digitizer dependant. Will try the shader instead.

Thanks again

john telfer's icon

Hi

I'm trying to deinterlace footage captured with jit.grab.

I need some very basic advice as to how to wire up the shader.

I've posted the patch with what I suppose are the basic elements needed.

Thanks

shader-test-1.maxpat
Max Patch
Rob Ramirez's icon

it's a texture processing effect, so you use jit.gl.slab.
also, you can enable output_texture on the jit.grab for improved performance, since you're going straight into GL land with the deinterlace shader.

Max Patch
Copy patch and select New From Clipboard in Max.

mike's icon

Hello Maxers,

I have to deinterlace a videostream comming from a Blackmagic Ultrastudio Mini Recorder. Using the attached camera only as a sensor, so i need a matrix to analyse the motion. So using a shader and grab the texture from the cpu would be a overhead ...

Is there a jit.pix which can do this ?
Or any other ideas ?

Best,
Mike

Rob Ramirez's icon

if you need matrix analysis, downsample in a texture and use jit.gl.asyncread to readback to matrix:

Max Patch
Copy patch and select New From Clipboard in Max.

mike's icon

whow, thanks a lot for your fast response and your patch Rob !
I tryed to avoid to run a opengl context just for deinterlace.
But I give your solution a try.
perhaps someone has a matrix (cpu) solution.
Best,
Mike