hello all
i just ran into a similar problem. for the logic of some video players we used the end 'bang' of [pix_film] for triggering some other filmplayer. as soon, as the movie should be started again, we first set the frame number to 1 and then in zero logical time we started the according [gemhead] to start film playing / rendering of the gemchain. by doing this, [pix_film] sent the end bang, although we've set the frame number to 1 before. it took me some time to figure out, that this is probably related to what you're discussing here. after i added a delay between setting frame no to 1 and starting [gemhead], it worked well (no bogus end 'bang' from [pix_film]). don't know how this could be solved in an meaningful and understandable way. however, i think that having to use a [delay] is the worst imaginable case. in this particular case, we found a clean solution by setting the startframe number on filmend instead of filmstart.
a generic solution to achieve something like that within 'pseudo-zero' logical time would be good, i think. by 'pseud-zero' logical time i mean, that instead of waiting to the left bang of [t b b], one could wait on the 'ready' bang from the [pix_[film|image|etc]] object.
roman
On Thu, 2008-10-30 at 10:32 -0400, Hans-Christoph Steiner wrote:
I agree. I think for any indeterminate operation, like anything in a separate thread, there should be a bang when that operation is complete. That way you can guarantee that things are ready when you run a process. If you want to make sure that things will be there on time, then these threaded/indeterminate operations should run well in advance. Using guesswork and delays is not a real solution...
.hc
On Oct 30, 2008, at 4:25 AM, cyrille henry wrote:
helo,
i'm also having this kind of problem. specially when loading a picture in pix_image. i think the best would be the have a bang when things are ready...
C
B. Bogart a écrit :
Hey all,
I'm having more and more problems with sync in PD. By sync I mean that parts of my patches have processing delays that mess up timing. In general I've been using buffers and delays to keep things working.
This approach is not very scalable.
I find myself using the "timer" object all the time to see if there is a processing delay I have to worry about. That is in cases where there is a bang saying an operation is done.
Two examples I'm working on now (in Gem):
First there is a delay between sending a message and the pix_buffer to store, and then again for pix_buffer_read to read the pixels. The delay is long enough that trigger does not work, there needs to be a delay to make sure the image in the buffer is the right one. (sometimes as much as 200ms)
A second example is that I'm using pix_share and and second PD instance to offload some CPU usage. Making sure the image sent to that PD instance and the image received later in the chain is difficult.
I'm not writing for specific advice, hence the generalities, but wanted to start a discussion on the issue.
What is the long-term solution for PD to solve these issues? Should all objects that introduce a delay send a bang when they are complete? (for example pix_buffer? Of course an additional delay occurs when when the pix_buffer is written to memory and when it gets to the gfx card for display.
I'm banging my head over these issues a lot lately and wonder if there is a better approach.
Back to attempting kludging a solution. .b.
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