andrea agostini

Maybe a trivial question, but I'm really clueless (and I don't want to go by trial and error!)

How do I convert from os ticks, as returned from systime_ticks, to ms? And would this allow me for sub-ms precision?

Right now I am more interested in the OSX answer, but also knowing about Win would not be bad...

Hi.
Maybe a trivial question, but I'm really clueless (and I don't want to go by trial and error!)
How do I convert from os ticks, as returned from systime_ticks, to ms? And would this allow me for sub-ms precision?
Right now I am more interested in the OSX answer, but also knowing about Win would not be bad...
Thank you!
aa


systime_ticks

... eventually, I have found out by trial and error - I was expecting some weird value, but it looks like we have 60 ticks per second on OSX, and - alas - no sub-ms precision.

If you are interested in rolling your own function, there is an example of getting potentially higher resolution here:

https://github.com/jamoma/JamomaFoundation/blob/master/library/includes/TTBase.h#L305

The time unit "tick" is defined in the Mac OS documentation. I could give you the chapter & verse from the original 

 from 1984, but you probably want something more recent;-) It's not changed since System 1.0.

BTW, not only is the tick not sub-ms, it's not even guaranteed to be absolutely accurate. It's not meant as anything like a sequencer clock, it is just an easy way to get timing for handling user interface events. For example, when a button is triggered by a keyboard shortcut, the button is supposed to invert for 8 ticks (eg, very roughly 1/8 second) as optical feedback. The amount of time that differentiates between a double-click and two separate mouse clicks is also defined in "ticks". IMS, on the original Mac hardware the tick counter was incremented by the vertical refresh of the built-in screen or something similar.

For sub-millisecond accuracy, you can use floating point with Max clock objects, but there are limits to the precision. For greater accuracy you will probably need to program directly to the OS APIs. It looks like Jamoma provides a wrapper function for this, but I don't know all the details.

The time unit "tick" is defined in the Mac OS documentation. I could give you the chapter & verse from the original Inside Macintosh from 1984, but you probably want something more recent;-) It's not changed since System 1.0.

For sub-millisecond accuracy, you can use floating point with Max clock objects, but there are limits to the precision. For greater accuracy you will probably need to program directly to the OS APIs. It looks like Jamoma provides a wrapper function for this, but I don't know all the details.


Very interesting info! I can't use Max's clock_fdelay and similar, because I am working in a new thread.

Looks like your example does what I need...

@Peter:
Very interesting info! I can't use Max's clock_fdelay and similar, because I am working in a new thread.

@Tim:
Looks like your example does what I need...