Thanks for the quick responses. This makes a lot more sense now.
Items don't get popped, they merely shuffle through. Clearly much
more useful that way, and exactly the delay line I was looking for.
Thanks again--
Greg
On Oct 26, 2008, at 4:05 PM, Alex Drinkwater wrote:
On 26 Oct 2008, at 22:53, Greg Best wrote:
Hello--
I can't find any documentation on how a queue works, exactly... It
takes a sequence of inputs, and outputs a structure. The patch
creator blurb says this is a FILO queue (which makes it more of a
stack than a queue?).
First question: when I access items from the structure at different
depths (indexes), am I popping off all of the items that I access,
or just the most recent? If difference the first and second
members of the structure, have I reduced the queue length by 1 or 2?
Reading items from the Queue has no effect on the length of the
Queue structure.
Second question: is there a FIFO available, as opposed to the FILO
queue? I'm not finding one...
No. But you can access the items in the Queue in reverse order.
Third question: aside from just wanting to know how these patches
work, I'm looking for away of comparing time separated frames from
a video input. In the simplest case, I'd like to be able to
subtract a video frame from the preceding frame (or a the frame
that occurred 5 frames earlier).
Very easy.
Connect your image to the Queue.
Connect two Structure Index Member patches to the Queue's outport.
Set the index for the first Structure Index Member patch to 0 and
the 2nd to 1.
The output of the first Structure Index Member patch will be the
newest image, and the 2nd will be the previous frame.
Use one of the Compositing patches to combine the 2 images.
Incidentally, you can use Queues for other kinds of data, too.
They're also very cool for control values.
Hope this helps,
a|x
http://machinedontcare.wordpress.com
Thanks--
Greg
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Quartzcomposer-dev mailing list ([email protected]
)
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/quartzcomposer-dev/the_voder%40yahoo.co.uk
This email sent to [EMAIL PROTECTED]
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Quartzcomposer-dev mailing list ([email protected]
)
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/quartzcomposer-dev/greglists%40me.com
This email sent to [EMAIL PROTECTED]
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Quartzcomposer-dev mailing list ([email protected])
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/quartzcomposer-dev/archive%40mail-archive.com
This email sent to [EMAIL PROTECTED]
