I was trying today to send image data from a maxpatch with one of the auvi-objects.
I had no problem getting the syphon stream via simple-client, but no luck within max using the jit.gl.syphonclient object or within VPT. I can select the syphon source, but no image comes through.
I have tried to add a gl-texture between the auvi object and the syphon server, but that didn´t make a difference.
I had some unexpected behaviour when I sent the syphon source to a mixer (v.001) object, with a qt source as the A source, and the syphon stream as B source. With the mix level at 50% I then saw the qt movie mixed with the syphon source (which so far had been invisible), but the closer I got to full mix for source B, the image faded to black. Is there some alpha weirdness going on?
Its been a while since I played with AUVI, but I recall those objects having serious alpha issues when using them with GL.
It is possible the matrix you are sending to jit.gl.syphonserver having a alpha plane full of 0, rather than 255. Try manually forcing the alpha to “1” on the AUVI objects, and see if that solves your issue.