[QLab] slowing down video file with Quartz

[Sander Loonen]

Hello all,

I have put up a small challenge for myself, and I was wondering if anyone could help me out.
For an upcoming production, I need to playback a video file which is simple enough, but then I need to slow it down a bit while playing back.
when the video designer told me this, I said fine. And thought I just make a quick quartz composition to do this.

this was quick enough, I have midi control over the speed of my quartz composition, and it all works.
then I published the input port of the patch, changed the name into "Image" and tried it through Qlab.
I hear the Audio play of the movie file but nothing on the screen. (I dont need the audio for the show, so I am not worried about that quality)
when I try to play the video through the video.qtz file included with Qlab it all works fine (I double checked with a blur filter just to be sure)

Is there anything I am missing, I really thought that all it took was to change the published name of the movie importer node to "Image"

I hope someone can help me, 'cause I dont want to be programming this really simple setup in Catalyst.

thanks

Sander
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[luckydave]

On Jun 7, 2011, at 4:35 PM, Sander Loonen wrote:

> then I published the input port of the patch, changed the name into "Image" and tried it through Qlab.

...

> when I try to play the video through the video.qtz file included with Qlab it all works fine (I double checked with a blur filter just to be sure)
>
> Is there anything I am missing, I really thought that all it took was to change the published name of the movie importer node to "Image"

The movie importer patch takes a file's location as its input. QLab passes frames of a movie file to Quartz as actual images. You need an Image input that matches what's coming in. The easiest thing to do would be to publish the input that the movie importer is connected to. Movie importer outputs an image, so it's connecting to an image as well. Publish that input, and QLab will pass frames to it.

I don't know if your speed control will work that way, though. QLab passes along one frame at a time, with its timestamp, so it's played at the right moment. So, it's not really a stream of video that you can slow down or speed up. I haven't tried it, but I think the solution I posted on the Wiki for using non-firewire cameras in Quartz might work for you. All Quartz needs from QLab is a constantly changing time. The image you send from your video cue could be discarded, and the Movie Importer patch in Quartz would load the actual video. So, you'd need a unique Quartz file for each cue, with file locations in each movie importer. It would be hell to move the show to another computer, but I think this would work. Here's the wiki reference:

http://wiki.figure53.com/QLab+Hints+and+Tips#x-Use Quartz Composer to access non-DV cameras (USB etc.)

(If that doesn't all act like a link, it's in the Hints and Tips section of the wiki.)

Thanks,
luckydave
luck...@figure53.com

[Sander Loonen]

Hi Lucky Dave,

thanks for the super fast response!
I have tried this, and the original camera patch, both to no avail.

however, it can very, very well be my computer.
the genius at the bar told me today (after a bit of testing that I need to have my logic board replaced.
so tomorrow when I get a loaner mac mini I will try on that.

it would make sense to me to use a separate quartz file for this slowing down effect and disregard the video (image stream) out of Qlab, but just use that as a trigger to keep quartz running.

I will let you know what my findings tomorrow will be

ciao

sander