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jit.gl.videoplane to render to jit.videoout?

March 6, 2007 | 12:19 pm

Anybody know how I get a matrix from jit.gl.videoplane to render to jit.videoout?

I am really stuck. Just read the tutorials or the tenth time. There is somthing I am just not seeing. :-(


March 6, 2007 | 1:03 pm

u probably need jit.gl.render to jit.window… sounds like u should dbl check tutorials on open gl in jitter.

j


March 6, 2007 | 4:26 pm

I have a working "Draw Context" and can draw to any style of window. The problem is nothing comes from the matrix out of these. If I do exactly the same thing with jit.glue instead of using jit.gl.videoplane to composite, I can take the output directly into jit.qt.videoout and it works.

So why do i not get any video from the matrix OUT of say a jit.pwindow, jit.matrix or jit.window (that is displaying my video) when using jit.gl.videoplane?

When using jit.glue I can just connect another jit.pwindow to the output of another jit.pwindow and see my video and pass it on) but with jit.gl.videoplane I get nothing from my matrix out

I used "@matrixout 1" and "@matrixout_enable 1" in the videoplane but to no avail. Not sure if these are right.


March 6, 2007 | 4:27 pm

I have a working "Draw Context" and can draw to any style of window. The problem is nothing comes from the matrix out of these. If I do exactly the same thing with jit.glue instead of using jit.gl.videoplane to composite, I can take the output directly into jit.qt.videoout and it works.

So why do i not get any video from the matrix OUT of say a jit.pwindow, jit.matrix or jit.window (that is displaying my video) when using jit.gl.videoplane?

When using jit.glue I can just connect another jit.pwindow to the output of another jit.pwindow and see my video and pass it on) but with jit.gl.videoplane I get nothing from my matrix out

I used "@matrixout 1" and "@matrixout_enable 1" in the videoplane but to no avail. Not sure if these are right.


March 6, 2007 | 5:20 pm

because of the fact that the GPU and the CPU are different, and when
using any jit.gl. objects you render right to openGL, and not an
intermediate matrix.

you can fall back to rendering to a named matrix, and then output
that matrix to a window, or render to a texture using @capture or
usetexture , to_texture to jit.gl.render.

basically, you have to do whats called ;’pengl readback’ to get data
off of the GPU. This is possible, search the archives.

On Mar 6, 2007, at 11:26 AM, Carl Rohumaa wrote:

>
> I have a working "Draw Context" and can draw to any style of
> window. The problem is nothing comes from the matrix out of these.
> If I do exactly the same thing with jit.glue instead of using
> jit.gl.videoplane to composite, I can take the output directly into
> jit.qt.videoout and it works.
>
> So why do i not get any video from the matrix OUT of say a
> jit.pwindow, jit.matrix or jit.window (that is displaying my video)
> when using jit.gl.videoplane?
>
> When using jit.glue I can just connect another jit.pwindow to the
> output of another jit.pwindow and see my video and pass it on) but
> with jit.gl.videoplane I get nothing from my matrix out
>
> I used "@matrixout 1" and "@matrixout_enable 1" in the videoplane
> but to no avail. Not sure if these are right.

v a d e //

http://www.vade.info
abstrakt.vade.info


March 6, 2007 | 5:34 pm

wouldnt it work to set a jit.matrix as the render destination? (as shown in tutorial 31) that works for me.

hc


March 6, 2007 | 5:59 pm

Yes, this definitely works. matrixout doesn’t work because that’s for
geometry, not the rasterized 3D scene.

wes


March 7, 2007 | 11:18 am

I have a working "Draw Context" and can draw to any style of window. The problem is nothing comes from the matrix out of these. If I do exactly the same thing with jit.glue instead of using jit.gl.videoplane to composite, I can take the output directly into jit.qt.videoout and it works.

So why do i not get any video from the matrix OUT of say a jit.pwindow, jit.matrix or jit.window (that is displaying my video) when using jit.gl.videoplane?

When using jit.glue I can just connect another jit.pwindow to the output of another jit.pwindow and see my video and pass it on) but with jit.gl.videoplane I get nothing from my matrix out

I used "@matrixout 1" and "@matrixout_enable 1" in the videoplane but to no avail. Not sure if these are right.


March 7, 2007 | 6:29 pm

On Mar 7, 2007, at 11:18 AM, Carl Rohumaa wrote:

>
> I have a working "Draw Context" and can draw to any style of
> window. The problem is nothing comes from the matrix out of these.
> If I do exactly the same thing with jit.glue instead of using
> jit.gl.videoplane to composite, I can take the output directly into
> jit.qt.videoout and it works.

A "draw context" does not produce a video matrix. It is an asset on
the GPU. You need to copy back to RAM to use as a video matrix in
some other jitter object. There are several ways to accomplish this.
A few of them are outlined in the jit.gl.render-tomatrix.pat example
patch (also on the Jitter FAQ), and you can also perform a render to
texture -> jit.matrix, but it is a more advanced feature, and it
sounds like you need to spend a bit more time reading the tutorials,
checking out the provided examples, looking at Andrew Benson’s Jitter
recipes, and searching the mailing list archives before really
getting into the render to texture path.

Neither does a jit.gl.* object with matrix output enabled not produce
a video matrix. As mentioned previously on the list, it is a
*geometry*matrix. Please see the Geometry Under The Hood appendix,
and relevant OpenGL object tutorials in the Jitter manual.

All this being said, I would also like to point out that what you’re
trying to do is probably going to be *really* slow. Readback from the
graphics card is a costly operation no matter how you do it, and
jit.qt.videoout requires a lot of CPU to compress your raw pixels
into the DV format. You are much better off from a performance
perspective outputting via DVI, VGA, or built in s-video output
depending on your needs. Each of these three possibilities let you
send directly from the GPU out to a device (no readback cost, no DV
compression cost).

-Joshua


March 8, 2007 | 10:54 am

Had a go at rendering to a named jit.matrix to a window but could not get anything out of the window matrix out. Although the video shows in the attached window.

Really happy though that I was able to do a readback and do software rendering. This really is a breakthrough in my understanding. As josh said it WAS "really slow" so I am now re-thinking.

I am going back to using jit.glue to composite my four videos. Then I will try to implement non realtime jit.qt.record.

I will then have to spigot the audio out of four QT movs and mix it back to stereo.

I hope that when I get this far the audio and video sync!

Thanks to Vade Josh and Wes, you really "told" me! ;)


March 31, 2007 | 8:52 am

http://www.opengl.org/discussion_boards/ubb/ultimatebb.php?ubb=get_topic;f=3;t=015006#000000

interesting links in that discussion to a readback benchmark on different
cards and a link to an nvidia developer article on the matter.
http://graphics.stanford.edu/projects/gpubench/results/
http://developer.nvidia.com/object/fast_texture_transfers.html
it refers there on PBO mode of transfer. i am not familiar with.
also mentioned there is methods to split the texture into several parts to
make this process faster.
most of it is above my understanding.

On 3/8/07, Carl Rohumaa wrote:
>
>
> Had a go at rendering to a named jit.matrix to a window but could not get
> anything out of the window matrix out. Although the video shows in the
> attached window.
>
> Really happy though that I was able to do a readback and do software
> rendering. This really is a breakthrough in my understanding. As josh said
> it WAS "really slow" so I am now re-thinking.
>
> I am going back to using jit.glue to composite my four videos. Then I will
> try to implement non realtime jit.qt.record.
>
> I will then have to spigot the audio out of four QT movs and mix it back
> to stereo.
>
> I hope that when I get this far the audio and video sync!
>
> Thanks to Vade Josh and Wes, you really "told" me! ;)
>


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