Hallo, Peter Plessas hat gesagt: // Peter Plessas wrote:
i have a question regarding timing in Pd:
I understand that messages to tilde objects just get passed to the DSP tree within DSP blocks.
How about the reverse?
Found out that snapshot~ is returning the last sample of the last block during which it got banged. This is fine, since it is the sample value most closely to the output of the result.
Now when i use the following setup:
[bang~] | | [t b b] | | | | [timer]
i get a minimum logical time of 1.45 msec (aquivalent to 64samples at 44.1 kHz) even when i use a blocksize of [block~ 32].
I think, bang~ should bang after each block, so with [block~ 32] it should bang every 32 samples. But it seems to have a lower limit of 64 samples. Don't know why.
In general, Pd has like to times: One is the time realm of clock-delayed messages, i.e. everything that originates in a clock objects like metro, delay, pipe, qlist, etc. Clock delayed messages have sub-sample accuracy. This is achieved by "tagging" each normal message with a time tag, similar to the old time tagged triggers in t3_lib. The tags for clocks are invisible, though.
To convert dsp signals to clock-delayed messages you must use [vsnapshot~], but [snapshot~]. It will give you the value of a sample even when bang'ed somewhere in the middle of a block.
Note that you cannot use this value to modify other samples during the same block! Because when the message comes out of [vsnapshot~], this block has already been calculated. So you can only start to use the value to modify the next block's content.
Ciao
Frank