[gmpi] Re: New Reqs 3.8 - Events

  • From: Chris Grigg <gmpi-public@xxxxxxxxxxxxxx>
  • To: gmpi@xxxxxxxxxxxxx
  • Date: Fri, 19 Dec 2003 11:22:47 -0800

But if in order to produce the relative timestamps the host has to do the absolute-->relative conversion before feeding events to the plug anyway, where's the optimization? Plug + host performance is about the same either way, no?

-- Chris G.

> No matter what, you always send the absolute timestamp at the start of the
process routine; call that the 'now' value. 

small optimisation: The absolute timestamp is not always needed, often the
relative ones are all you need.  So in SynthEdit for example, to save CPU,
the absolute timestamp is not passed to the plugin. The plugin can ask the
host for it if needed though.

Best Regards,
Jeff


----- Original Message -----
From: "Tim Hockin" <thockin@xxxxxxxxxx>
To: <gmpi@xxxxxxxxxxxxx>
Sent: Friday, December 19, 2003 3:46 PM
Subject: [gmpi] Re: New Reqs 3.8 - Events


 On Thu, Dec 18, 2003 at 11:55:11PM -0500, Michael Gogins wrote:
 > Then I don't understand the distinction between absolute and relative
 > timestamps. It seems to me that what I have described is absolute
 > timestamps.

OK, let me explain it as I understand it:

 No matter what, you always send the absolute timestamp at the start of the
 process routine; call that the 'now' value.

 Absolute timestamps put a 64-bit value on each event which represents the
 absolute time of the event on the same timeline as 'now'.  An event which
is
due 5 samples into the buffer has a timestamp of (now + 5).

 Relative timestamps put a 32-bit value on each event which represents the
 offset of the event relative to 'now'.  An event which is due 5 sampled
into
the buffer has a timestamp of 5.

The difference is mostly a usage pattern.


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