Jack Henderson

I have an issue running a Jitter patch on a PC, which is incredibly simple and works fine on a mac. There must be something I'm doing wrong, but I always assumed Jitter was interoperable between systems. I've tested the PC itself, and it seems to be working well otherwise.

Here is a patch showing my problem. A jit.grab @output_texture 1 object opens a webcam succesfully on both devices (I have included a jit.pwindow to check), but on the PC it doesn't render to jit.world. This seems really simple but I can't for the life of me work out why this is happening. My gl engine is 2.

I'm generally finding Jitter extremely unreliable, with loads of glitches and errors - patches working stably for several days then not a few days later without any changes (accross several different machines and Os's too). I'm sure it's something I'm doing, but I didn't used to have these sorts of problems with it, especially as I'm running extremely simple patches, by and large.

I know PCs address webcams differently - you can't share them between apps - but the fact it is opening in Max fine and can be viewed in jit.pwindow would suggest this isn't the problem.

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I know PCs address webcams differently - you can't share them between apps - but the fact it is opening in Max fine  and can be viewed in jit.pwindow would suggest this isn't the problem.

Hi,
I have an issue running a Jitter patch on a PC, which is incredibly simple and works fine on a mac. There must be something I'm doing wr

simple-jitter-patch-works-on-mac-but-not-pc

I've found another example of a discrepancy between Mac and Windows.

When I use a webcam feed into a jit.matrix, and then send the jit.matrix the message 'exportimage filename jpg' on a Mac it creates a jpg with the last frame fed to the matrix (as per helpfile, and as you'd expect), but on a PC the JPEG is blank (a black image of the matrixes dimensions).

Judging from the fact it works on the mac, and that it's implementing a very simple and well documented function from jit.matrix, can anybody think why it doesn't work on a PC? I'm copying the exact max patch between computers, so I'm very puzzled by this.

EDIT: To clarify, on the PC the webcam is definitely feeding into max, and even being output by the matrix (i.e. a jit.pwindow shows the image is coming out of the matrix), so it seems like something is happening with the 'exportimage' which is different between the OSes.

EDIT 2: Look like the conversion from webcam to texture and back was making the alpha channel set everything black. I would definitely say this still must be some sort of bug due to the fact it behaves differently on mac and PC (although would be interesting to see if this is every PC, or just the ones in front of me).

I believe both of these issues are the same bug, which is that jit.grab on windows outputs a zero value alpha plane when output_texture is enabled. this was fixed a while back for matrix output, but I guess not for texture output unfortunately. I will ticket and get this fixed up. Thanks much for the report!

in the meantime, and easy workaround that is efficient and cross-platform is a simple jit.gl.pix object to pack in a full valued alpha plane:

I believe both of these issues are the same bug, which is that jit.grab on windows outputs a zero value alpha plane when output_texture is enabled.  this was fixed a while back for matrix output, but I guess not for texture output unfortunately. I will ticket and get this fixed up. Thanks much for the report!

Ah yes - that makes sense. I had already used a workaround using jit.gen, but this is much more efficient. Thanks!

Simple Jitter patch works on Mac but not PC