Fedde

When I am using a jit.movie on a jit.gl.videoplane / cornerpin or gridshape and I scale it down or reposition it on the z-axis I see a lot of pixelation. When using the same screen size in a osx quicktime player this is not happening. Maybe some of you can give me a clue about what is going on here? Do I need to set an interpolation function or am I missing something else? I have attached a screeshot to show what I mean. See the right arm of the lady.

When I am using a jit.movie on a jit.gl.videoplane / cornerpin or gridshape and I scale it down or reposition it on the z-axis I see a lot of pixelation. When using the same screen size in a osx quicktime player this is not happening. Maybe some of you can give me a clue about what is going on here?  Do I need to set an interpolation function or am I missing something else? I have attached a screeshot to show what I mean.  See the right arm of the lady.


bad-resolution-jit-movie-on-a-jit-gl-videoplane-cornerpin-gridshape

The video dozer.mov is a 320 x 240 resolution.

When you press escape and make this full screen then the pixelation is very obvious.

You can't add what isn't there in the 1st place.

If i would load a film that was high quality with a resolution of 1440 x 900 then there would be no pixelation. Also codec dependant.

Any resolution lower than what your display is will have pixelation.

Solution. a higher quality video which fits the screen size.

I've attached a patch which shows no interpolation with jit.gl.texture and your original film, click the gswitch to see the difference.

The video dozer.mov is a 320 x 240 resolution.
When you press escape and make this full screen then the pixelation is very obvious.
You can't add what isn't there in the 1st place.
My monitor is 1440 x 900
If i would load a film that was high quality with a resolution of 1440 x 900 then there would be no pixelation. Also codec dependant.
Any resolution lower than what your display is will have pixelation.
Solution. a higher quality video which fits the screen size.
I've attached a patch which shows no interpolation with jit.gl.texture and your original film, click the gswitch to see the difference.
Hope this makes things clearer.


The screenshot from my first post is 1920 1080 footage. Look at the right arm of the lady on the right picture and then the left picture. What I mean is maybe not a resolution issue. When you scale a videoplane, gridshape plane or whatever to a smaller size or reposition it further away on the z-axis you start to see distorted lines / pixels. When it has a larger size this is not/less perceivable.

It frustrates me a bit and makes me doubt if the GL implementation in Max Jitter is suitable for this project. What I want to do is project video footage on multiple, not so large, 16:9 panels using one projector.

The screenshot from my first post is 1920 1080  footage. Look at the right arm of the lady on the right picture and then the left picture.  What I mean is maybe not a resolution issue.  When you scale a videoplane, gridshape plane or whatever to a smaller size or reposition it further away on the z-axis you start to see distorted lines / pixels. When it has a larger size this is not/less perceivable.  

It frustrates me a bit and makes me doubt if the GL implementation in Max Jitter is suitable for this project. What I want to do is project video footage on multiple, not so large, 16:9 panels using one projector.


Check the jit.window object with fsaa 1 (full screen anti aliasing)

If your going to change the aspect ratio of any video artifacts will always occur.

You can also capture the jit.gl.videoplane object with a jit.gl.node and enable fsaa (could be on by default with max 7).

Open GL is fine for this, it can do it all that and more.

Your just lacking some experience with how to work with it.

I use madmapper with multiple screens and just have all my films each on a jit.gl.videoplane. No problem.

if you use a jit.gl.videoplane scale 1. 1. 1. then this isn't a 16:9 ratio is it ?

Lets just say that your width with 1920 is 100 units for arguments sake. (x scale of videoplane)

then the height has to be 56 units to maintain the correct aspect ratio and not distort the image.

Roughly converted the correct size would be (you'll have to play with it)

DId you try my patch with your video ?
Check the jit.window object with fsaa 1 (full screen anti aliasing)
If your going to change the aspect ratio of any video artifacts  will always occur.

Open GL is fine for this, it can do it all that and more.
Your just lacking some experience with how to work with it.

I use madmapper with multiple screens and just have all my films each on a jit.gl.videoplane. No problem.
if you use a jit.gl.videoplane scale 1. 1. 1. then this isn't a 16:9 ratio is it ?
Lets just say that your width with 1920 is 100 units for arguments sake. (x scale of videoplane)
then the height has to be 56 units to maintain the correct aspect ratio and not distort the image.
Roughly converted the correct size would be (you'll have to play with it)
jit.gl.videoplane scale 1.92 1.08 1.


Yes I tried it. Thank you for that. I was aware about the aspect ratio. I am aware of the capabilities of open gl.

But I still don't understand why stuff is getting so pixelated when moving it to a far position along the z-axis.

Yes I tried it. Thank you for that. I was aware about the aspect ratio. I am aware of the capabilities of open gl. 

But I still don't understand why stuff is getting so pixelated when moving it to a far position along the z-axis.


Post your patch without the video. I'll see if it also happens on my system.

downsampling artifacts are tricky to get rid of. you need to pass through a jit.gl.texture with @rectangle 0 and explicitly set the dimensions to a power of 2. you can then change the @mipmap attribute to bilinear or trilinear to handle these artifacts.

Thats a proper trick Rob. Thank you for pointing it out. But on the other hand the image gets a bit blurry on some stages, maybe unnecessary. I still don't know enough about graphic processing.

bad resolution jit.movie on jit.gl.videoplane / cornerpin / gridshape