Hallo, martin.peach@sympatico.ca hat gesagt: // martin.peach@sympatico.ca wrote:
Frank Barknecht wrote: I think, it's comport's fault: [metro] generates clock-delayed messages. These are like messages tagged with a time-stamp referring to Pd's internal clock. However an object needs to actually use the time-stamps and "look at the clock" to see what time it is. Objects like [vline~] or [delay] do this, but comport doesn't.
(Actually I may be wrong here: Maybe comport doesn't need to do anything about this, as it's not a dsp-object. But read on.)
Well that's interesting! How does one access these timestamps? I thought a bang has no associated info.
Well, there are no "real" timestamps attached to a bang-message. But Pd has a clock running (actually many, sync'd to the main scheduler clock), and objects that want to know the current time a message arrives, need to look at the clock.
vsnapshot~ for example (d_ctl.c) seems to do it like this: In its dsp-perform routine, which is called every sample block, it stores the current time with "x->x_time = clock_getlogicaltime();" Then in the bang-routine, vsnapshot~ uses "int indx = clock_gettimesince(x->x_time) * x->x_sampspermsec;" to calculate the correct index into the incoming sample block from the difference between the time stored previously and the current time. This is what I meant with "looking at the clock".
Objects like [delay] or [metro] produce these clock-delayed messages. They register their clocks with Pd's main scheduler using clock_new(...) and then order the scheduler to generate the clock-delayed messages like the metro-bangs using clock_delay(). The actual output of [delay], [metro] etc. then is initiated by the scheduler which calls the registered clock methods: delay_tick(), metro_tick(),...
However I must admit, I'm not sure how this relates to comport and if comport should also register its port-writing-method with a clock and let the scheduler "tick" the clock and initiate the writing and if that could get rid of the jitter you mentioned.
At least "normal" objects like [float] don't do any funky clock-stuff and still don't disturb the correct timing of clock-delayed messages.
Ciao
Frank Barknecht _ ______footils.org_ __goto10.org__