Maarten

I want to use jit.brcosa with colormode uyvy, however when I use that

colormode I loose a intuitive use of jit.brcosa, Is there another way

to achieve brightness contrast and saturation adjustments besides

I want to use jit.brcosa with colormode uyvy, however when I use that
colormode I loose a intuitive use of jit.brcosa, Is there another way
to achieve brightness contrast and saturation adjustments besides
doing it in argb mode?

jit-brcosa-with-colormode-uyvy

Have you taken a look at the stuff on color tinting

and saturation in Tutorial 49? At the very least,

it's quite a good description of what you're actually

*doing* in the other colorspace (besides trying to

Have you taken a look at the stuff on color tinting
and saturation in Tutorial 49? At the very least,
it's quite a good description of what you're actually
*doing* in the other colorspace (besides trying to
increase performance :-) ).


On May 25, 2006, at 11:32 AM, Maarten Zeinstra wrote:

> I want to use jit.brcosa with colormode uyvy, however when I use that

> colormode I loose a intuitive use of jit.brcosa, Is there another way

> to achieve brightness contrast and saturation adjustments besides

jit.brcosa is ARGB specific. We do not provide UYVY objects for the 

CPU, as we use it primarily as a mechanism for fast transfer to the 

GPU (where more significant video processing performance boosts 

occur). You can of course do this processing with generic math 

objects on the CPU if you desire to. Or perform these operations on 

On the CPU, for fastest processing in this fashion on UYVY data, I 

might suggest jit.charmap. Brightness + contrast as a linear ramp 

applied to the two YY planes, and saturation as a linear ramp applied 

to the U and V planes. A two minute hack from jit.charmap.help which 

illustrates the concept is below. For more information. I would 

suggest reading the colorspace tutorial, and checking out jitter- 

examples/video/uyvy/, and reading online literature on the YUV 

For most spatial operations (such as rotation, or convolution) on the 

chroma reduced UYVY data, you typically want to move to a full chroma 

format such as AYUV or ARGB before applying them.

> I want to use jit.brcosa with colormode uyvy, however when I use that
> colormode I loose a intuitive use of jit.brcosa, Is there another way
> to achieve brightness contrast and saturation adjustments besides
> doing it in argb mode?

jit.brcosa is ARGB specific. We do not provide UYVY objects for the  
CPU, as we use it primarily as a mechanism for fast transfer to the  
GPU (where more significant video processing performance boosts  
occur). You can of course do this processing with generic math  
objects on the CPU if you desire to. Or perform these operations on  
the GPU with jit.gl.slab.

On the CPU, for fastest processing in this fashion on UYVY data, I  
might suggest jit.charmap. Brightness + contrast as a linear ramp  
applied to the two YY planes, and saturation as a linear ramp applied  
to the U and V planes. A two minute hack from jit.charmap.help which  
illustrates the concept is below. For more information. I would  
suggest reading the colorspace tutorial, and checking out jitter- 
examples/video/uyvy/, and reading online literature on the YUV  
colorspace.

For most spatial operations (such as rotation, or convolution) on the  
chroma reduced UYVY data, you typically want to move to a full chroma  
format such as AYUV or ARGB before applying them.

and for the sake of the archive, here's a version that uses javascript to calculate the charmap clut....

var brcosa = new JitterMatrix(4,"char",256,1);

        brcoramp[i]=Math.floor(255*((b_ * c) - c_));

        satramp[i]=Math.floor(255*((i_ * s) - s_));

        brcosa.setcell(i, 0, "plane", 1, "val",brcoramp[i]);

        brcosa.setcell(i, 0, "plane", 3, "val",brcoramp[i]);

        brcosa.setcell(i, 0, "plane", 0, "val",satramp[i]);

        brcosa.setcell(i, 0, "plane", 2, "val",satramp[i]);

    outlet(0,"jit_matrix",brcosa.name);

outlets=1;
var brcosa = new JitterMatrix(4,"char",256,1);

function bcs(b,c,s){
	var brcoramp = new Array();
	var satramp = new Array();
	var c_ = (c-1)/2;
	var s_ = (s-1)/2;
	for (i=0;i
		var i_ = i/255;
		var b_ = b+i_;
		brcoramp[i]=Math.floor(255*((b_ * c) - c_));
		satramp[i]=Math.floor(255*((i_ * s) - s_));
		brcosa.setcell(i, 0, "plane", 1, "val",brcoramp[i]);
		brcosa.setcell(i, 0, "plane", 3, "val",brcoramp[i]);
		brcosa.setcell(i, 0, "plane", 0, "val",satramp[i]);
		brcosa.setcell(i, 0, "plane", 2, "val",satramp[i]);
	}
	outlet(0,"jit_matrix",brcosa.name);
}
//--------------end uyvy_brcosa.js

Has someone a jxs file that process brcosa or any in uyvy mode ?

Theres's noone in shaders folder, it seems out of my competence to write in glgs ...

Hey Sir pnyboer, do you think your uyvy_brcosa.js 'less gluttonous than the .pat one ?

Has someone a jxs file that process brcosa or any in uyvy mode ?
Theres's noone in shaders folder, it seems out of my competence to write in glgs ...
Is there a solution ?

On Mar 23, 2007, at 8:01 AM, derrickgiscloux wrote:

> Has someone a jxs file that process brcosa or any in uyvy mode ?

> Theres's noone in shaders folder, it seems out of my competence to 

On the graphics card uyvy is converted to rgba, so there is no need, 

unless you are trying to keep your data as uyvy somehow.

For the ambitious, one can masquerade uyvy data as rgba data, process 

as such and return to the CPU in uyvy format. For the video to be 

rendered to the screen with expected colors on the GPU you have to 

perform the uyvy to rgba conversion at some point. Some potentially 

- /jitter-examples/render/slab/jit.gl.slab-uyvy-gpu.pat

Perform your own uyvy to rgba conversion on the GPU (highly 

recommended on Windows, and even recommended on Mac for color 

correction and chroma smoothing which isn't present in the Apple UYVY 

texture implementation). If you don't want to convert to RGBA for 

whatever reason (though as mentioned you'll need to if you want to 

make visible on your monitor), you could eliminate the color 

conversion portion of this shader and just exploit he brightness, 

contrast, and saturation processing that this shader provides in the 

- /jitter-examples/render/slab/jit.gl.slab-uyvy-readback.pat

Perform your own rgba to uyvy conversion on the GPU, optionally for 

readback. This can be useful for improving performance of data 

readback patches, and other situations where you want to process the 

data in the UYVY format on the GPU. Since OpenGL has no concept of 

UYVY, you need to use a shader like this.

- /jitter-examples/render/slab/jit.gl.slab-grgb.pat

Similar to the above, but you can work with chroma reduced GRGB data 

(green is the majority of luminosity, so this is the roughly RGB 

colorspace equivalent of chroma reduced UYVY data).

Hope this at least gives you some starting points for your 

> Has someone a jxs file that process brcosa or any in uyvy mode ?
> Theres's noone in shaders folder, it seems out of my competence to  
> write in glgs ...
> Is there a solution ?

On the graphics card uyvy is converted to rgba, so there is no need,  
unless you are trying to keep your data as uyvy somehow.

For the ambitious, one can masquerade uyvy data as rgba data, process  
as such and return to the CPU in uyvy format. For the video to be  
rendered to the screen with expected colors on the GPU you have to  
perform the uyvy to rgba conversion at some point. Some potentially  
useful and illustrative patches below:

- /jitter-examples/render/slab/jit.gl.slab-uyvy-gpu.pat
Perform your own uyvy to rgba conversion on the GPU (highly  
recommended on Windows, and even recommended on Mac for color  
correction and chroma smoothing which isn't present in the Apple UYVY  
texture implementation). If you don't want to convert to RGBA for  
whatever reason (though as mentioned you'll need to if you want to  
make visible on your monitor), you could eliminate the color  
conversion portion of this shader and just exploit he brightness,  
contrast, and saturation processing that this shader provides in the  
UYVY data.

- /jitter-examples/render/slab/jit.gl.slab-uyvy-readback.pat
Perform your own rgba to uyvy conversion on the GPU, optionally for  
readback. This can be useful for improving performance of data  
readback patches, and other situations where you want to process the  
data in the UYVY format on the GPU. Since OpenGL has no concept of  
UYVY, you need to use a shader like this.

- /jitter-examples/render/slab/jit.gl.slab-grgb.pat
Similar to the above, but you can work with chroma reduced GRGB data  
(green is the majority of luminosity, so this is the roughly RGB  
colorspace equivalent of chroma reduced UYVY data).

Hope this at least gives you some starting points for your  
investigations.