Cycling 74 » Topic: Record Geometry as a File http://cycling74.com/forums/topic/record-geometry-as-a-file/feed Wed, 19 Jun 2013 13:30:29 +0000 http://bbpress.org/?v=2.2.4 http://cycling74.com/forums/topic/record-geometry-as-a-file/#post-63092 <![CDATA[Record Geometry as a File]]> http://cycling74.com/forums/topic/record-geometry-as-a-file/#post-63092 Thu, 19 Apr 2012 16:04:55 +0000 lembert.dome I would like to record a stream of geometry matrix frames as a file. In essence, this is just the same as recording video, but does not work with jit.qt.record and jit.qt.movie. Does anyone have an idea how to do this?

It is possible to save individual frames as .jxf files, but the jit.qt objects presumeably treat the matrix stream as video and change the data.

Here is a patch to demonstrate the problem:

– Pasted Max Patch, click to expand. –
]]> http://cycling74.com/forums/topic/record-geometry-as-a-file/#post-227664 <![CDATA[Re: Record Geometry as a File]]> http://cycling74.com/forums/topic/record-geometry-as-a-file/#post-227664 Thu, 19 Apr 2012 23:56:26 +0000 lembert.dome I tried a few more things, but without real success. Here is the same patch with some additions:

– Pasted Max Patch, click to expand. –

Ah. Here is the solution. Use jit.matrixset. That is fine for shorter clips, but it would not work for a longer video (such as recording the depth-matrix of a Kinect camera.) It makes sense; jit.qt.record is an interaction with Quicktime, which is for video.

Here is the patch:

– Pasted Max Patch, click to expand. –
]]> http://cycling74.com/forums/topic/record-geometry-as-a-file/#post-227665 <![CDATA[Re: Record Geometry as a File]]> http://cycling74.com/forums/topic/record-geometry-as-a-file/#post-227665 Fri, 20 Apr 2012 19:05:44 +0000 Andrew Benson I have a (really nerdy) solution for this. The barrier with jit.qt.record is that the matrix has to be a 4-plane char matrix for it to work right. We want 3 plane float32, what do we do? We use jit.coerce to treat each plane of the matrix as a 4-plane char one. Since char is 8-bits per plane, and float32 is well 32-bits per plane we keep the same bits but just represent them differently. To jam it all back together, we can just use jit.glue and voila we have something jit.qt.record can deal with natively. To read back in, you can use jit.qt.movie and just do the whole thing in reverse.

For another example of this, check Recipe 15: GestureRecord http://cycling74.com/2006/02/14/jitter-recipes-book-2/

and here’s the patch:

– Pasted Max Patch, click to expand. –
]]> http://cycling74.com/forums/topic/record-geometry-as-a-file/#post-227666 <![CDATA[Re: Record Geometry as a File]]> http://cycling74.com/forums/topic/record-geometry-as-a-file/#post-227666 Fri, 20 Apr 2012 19:56:18 +0000 Jesse This is very cool! Works on playback with some slight modification to your patch Andrew.

So if one wanted to record Kinect data (as lembert has indicated) the resulting QT file would be 1920×480 RAW? If I’m calculating correctly that’s ~3.6MB/sec, which is quite doable writing to a single disk.

Great solution!

]]> http://cycling74.com/forums/topic/record-geometry-as-a-file/#post-227667 <![CDATA[Re: Record Geometry as a File]]> http://cycling74.com/forums/topic/record-geometry-as-a-file/#post-227667 Fri, 20 Apr 2012 22:21:10 +0000 lembert.dome Thank you Andrew!
That is precisely the sort of insight I was hoping for. I tried your patch briefly with a Kinect. It works but introduces some strange artefacts. I may have recorded the data incorrectly. I’ll figure them out and repost.

@Jesse:
You would not have to record the reformatted matrix for the shatter patch; just the initial Kinect data with the dimensions of 640×480 (or less).

Yes, this is a very useful patch for me.

]]>