Closed for Company Meetings: Between September 18 (5pm PDT) and September 22 (12pm PDT), Support and Sales requests will be delayed. Only time-sensitive issues will be addressed during that time. Thanks for your patience.
actually I just discovered another object that helps with this: jit.gl.asyncread
this acutally gives you a matrix, while the above gives you a texture. for your case the above code should be better, since your captured texture stays on the GFX card and is beeing passed directly to syphon, which is using a kind of shared GFX-Texture (I think) instead of passing it to CPU (matrix) and then to GPU (texture again) and Syphon.