Image Pixel and Quicktime export

snerg's picture


I'm using the "Image Pixel" patch to read the RGB values from a image/movie and process them, this is working fine in Quartz Composer 3.0 (63).

I exported the composition to Quicktime in QC3 and import it in Final Cut Express to render (it doesn't run faster then 6 fps realtime).

However in Final Cut Express the "Image Pixel" patch doesn't seem to work at all, the composition looks all bad because the "Image Pixel" output is not working (it returns all white pixels). So now I can't render my work :(

Any help would be welcome!


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cwright's picture

The Image Pixel patch is declared "unsafe", so it doesn't load in safe-mode protected environments. When QC exports a MOV, it doesn't actually render, it just puts the qtz in a .mov, and then has the .mov player render it. This doesn't always work properly though, as you've probably noticed.

We're developing an application (Quartz Crystal) that properly renders qtz's to movs, but it's still fairly experimental. If you can, can you send the composition to the e-mail address at the bottom of each page (, and I'll try it through Quartz Crystal to see if it works. If so, I can send you an alpha version of the app for further use.

snerg's picture
Hi, Thanks for the quick


Thanks for the quick reply!

I didn't know about "unsafe patches", I just found the option "Indicate unsafe patches" in the Editor menu of QC3, which will probably prove useful.

This is a very simple example patch to illustrate the problem:

I'd love to hear if it renders in Quartz Crystal!


cwright's picture

Here's the rendered version of that composition. looks like it worked. I'm in the middle of running around at the moment, but I'll try to fire off a test version shortly.

image pixel test.mov221.7 KB

snerg's picture
It seems to be working

It seems to be working :)

The output of the test-file isn't very interesting, so I took some screenshots to show you what I'm working on.

It would be great to render my work to video, I'm looking forward to it.


psonice's picture

oooh, sounds good! Will it support audio?

Either way I'll be glad to remove the plugin that allows unsafe patches :)

If you want it testing, I have some mamoth compositions with really nasty timing stuff that's a real headache to capture :)

cwright's picture
no audio :(

There are a bunch of limitations to off-line rendering. There's no good way to get audio into or out of QC reliably (without creating some custom patches designed for offline audio). There's also no good way to handle input (mouse, keyboard, live video)... but for places where that's not a concern, the output is amazing :)

psonice's picture
It works!

Proof: :)

I can think of ways to handle both audio and input, but neither are particularly nice.

For input: do a 'test run' where the composition just plays, and input/video is enabled. Record the keyboard, mouse, and any video input, then feed it back into QC for recording. I can see a few issues with that, but it might be possible...

Audio: if your experience is anything like mine, the audio plays realtime while the composition doesn't. I think this is easier to handle. You need to capture the audio first (getting the path from the .qtz file is fairly easy). Then actually disable (or mute) audio output from quartz, and play back one frame worth of audio data for each frame rendered - depending on how QC captures audio, it might need looping until the frame has finished rendering. Again, it 'might' be possible... :)

Anyway, big thanks once again for all the work on this and all the rest!

snerg's picture
I also did a little

I also did a little render...

It sure is working, thanks a lot!


psonice's picture

Cool, we're working on similar stuff. I'm using the texture to displace a grid though, instead of using cubes. It might not look like it, but the smoke attempt I posted uses the same method, but wrapped around a sphere. Here's a more recognisable one:

(guess I should point out that the texture and displacement map are shamelessly stolen (for convenient test purposes only!) from this demo: - which is awesome, not that you'd expect less from mfx :)

toneburst's picture
Cool. I did something like

Cool. I did something like that a while back. Dunno if you used the same method as me, but it's a nice effect. You can also try cylinders or cones instead of cubes, which looks quite cool too.


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