[gmpi] Re: Topic 6: Time representation
- From: Martijn Sipkema <m.j.w.sipkema@xxxxxxxxxxxxxxxxxx>
- To: gmpi@xxxxxxxxxxxxx
- Date: Tue, 29 Apr 2003 15:22:37 +0100
> Is time represented as samples or "ticks" or both/neither? How are
> discontinuities in the timeline expressed?
I'd suggest using samples for time representation, but this will probably
not work for MIDI processing plugins, i.e. plugins not handling audio.
> My stake in the ground is that we need a way to represent time either in
> musical units or absolute units. The units should be chosen in such a way
> to avoid rounding errors when converting from one to the other, and should
> also support at least 24 hours of time range.
Is musical time really needed apart from using MIDI clock messages to do
tempo based effects? You'd also need to enable the plugin to access the
tempo map for absolute musical time to be useful (or at least the time of
the last tempo change and the tempo).
> By way of example, SONAR uses a representation where a 64-bit structure
can
> represent either a floating point absolute time, or an integer musical
time
> in units of 960*(2^16) PPQN. (The choice of PPQN makes conversions to a
> user editable 960 PPQN efficient.) Conversions are done via a host
supplied
> time converter interface.
Why use a floating point value for absolute time and not use a signed 64 bit
integer (with nanosecond resolution)?
--ms
----------------------------------------------------------------------
Generalized Music Plugin Interface (GMPI) public discussion list
Participation in this list is contingent upon your abiding by the
following rules: Please stay on topic. You are responsible for your own
words. Please respect your fellow subscribers. Please do not
redistribute anyone else's words without their permission.
Archive: //www.freelists.org/archives/gmpi
Email gmpi-request@xxxxxxxxxxxxx w/ subject "unsubscribe" to unsubscribe
Other related posts:
