Changing Video Coordinates

Apr 10, 2012 at 5:41am

Changing Video Coordinates

Okay, Im not sure if this is in the correct place so please correct me if I am wrong as I am knew to this. I do have some Max MSP knowledge but I am stumped.

I am looking to take the silhouette of a person, the video of a silhouette anyway and move the movie through a space. I can’t seem to figure out a way to move the video based on an x coordinate. I managed to do so with a picture but I need to control the video speed based on the change in x. and change the x coordinates of the video based on the x coordinate I give to the patch. Let me know if you need any more information as this is somewhat hard to explain. Any and all help would be amazing! Thanks in advance!

#62870
Apr 10, 2012 at 5:58am

I am confused by your request. You seem to be asking two things:

1. How to move part of a video (a silouette) around the window
2. How to also change the rate of that video based on its x-coordinate.

First, the easiest way to move videos about the window is to use jit.gl.videoplane.

Second, the x-position (in this case a gl coordinate, not a pixel-position) can simply be scaled and fed into the rate of the jit.qt.movie, or you can be controling which frame is being shown using the frame $1 command to the jit.qt.movie.

#226967
Apr 10, 2012 at 6:17am

Thanks for the quick response!

Basically I have a looping video. The silhouette which is suposed to represent a shadow. In the pictures attached I managed to move just a still image through the space attached to the x coordinate. The x coordinate will be associated with a person moving through a given space and I am attaching my own shadow to their feet. So when the person stops. or the X coordinate stops I want the video to stop. But when the person is moving I want the video to be playing or looping.

1. How to move part of a video (a silhouette) around the window

somewhat. It is only the silhouette in the movie. so If I can find a way to move the entire movie move that would work.

2. How to also change the rate of that video based on its x-coordinate.

Yes the faster the x-coordinate is changing the faster the movie is playing. And if the x coordinate is not moving or stopped the video will loop slowly or stop.

Thanks again! I will look into jit.gl.videoplane and see if this helps!

[attachment=190657,3679] [attachment=190657,3680]

Attachments:
  1. ScreenShot20120409at11.07.38PM.png
#226968
Apr 10, 2012 at 7:09am

Ok the Jit.gl.videoplane seems to be working perfectly. The only question I still have is if there is any way that I can make the change in x change the framerate on a video. Basically if the x coordinate is 15 in one frame and 13 in the next compared to 15 in one fram and 8 in the next. The one with the change of 7 will make the movie loop faster than the change of 2 where it should go slower. Thanks again!

#226969
Apr 10, 2012 at 4:10pm

You want to scale your rate of change in X to your video’s playback rate. If you are dealing with isolated changes in X, this patcher will work for you:

– Pasted Max Patch, click to expand. –

If, however, you have a stream of X values and you need to calculate their rate of change, you need a different strategy.

#226970
Apr 10, 2012 at 10:54pm

Ya I will be streaming the coordinates in from a program pulling the x coordinates from a kinect.

#226971
Apr 11, 2012 at 12:47am

Aha. Here are two suggestions:

For the silouette, take a look at the last patch on this page:
http://cycling74.com/forums/topic.php?id=38963
Use [pak position 0. 0. 0.] to position the mesh in the window.

For the speed of the video, try a variation of this:

– Pasted Max Patch, click to expand. –
#226972

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