Ralf Mardorf wrote:
Arnold Krille wrote:
On Tuesday 15 June 2010 17:55:56 Paul Davis wrote:
On Tue, Jun 15, 2010 at 11:27 AM, James Morris <ja...@jwm-art.net>
wrote:
Incidentally, if I want the GUI to update very close to real time, say
a grid of blocks flashing on and off as notes come and go, any
thoughts? Would a GTK GUI update fast enough?
key insight: your display monitor only redraws between 60 and 90 times
per second. attempting to redraw anything more frequently than this is
simply wasting CPU cycles and making your life more difficult. put
more bluntly: it doesn't matter if you have notes turning on and off
1000 times per second - you and your users not working on a display
device that can possibly show this.
Unless you make your lights "slowly" go on an off with transitions,
there isn't even a need to be faster then 25 or 30 updates per
second. The slowest part here is the human eye. And the requirement
for >60Hz refresh rate for pictures comes from the good old days of
CRT screens.
Arnold
Because I'm doing graphical art work some times I still prefer old
faithful CTR screens, currently the refresh rate of my monitor is at
89.9 Hz. But to be honest, the MIDI-thru-box I build in the 80ies and
I'm still using it today, has a LED and the light is 'slowly' ... we
aren't birds ... humans are fine with less than 30 frames/second for
films and I guess nobody, excepted of some autistic people, are/is
able to count how often a light is turning of and on within e.g. 30
frames/second, but we notice any refresh rate under 75 Hz.
Regarding to updates for real-time GUIs it might be not important to
display a virtual LED showing each MIDI event, but I can confirm that
an ATARI ST + blitter (a coprocessor) has a more real-time near GUI
for MIDI events, than Linux on my 2.1 GHz dual-core AMD. I'm not sure
if it's needed. I also did use Atari STs without a blitter and the
GUIs are less real-time than my Linux machine.
But this reminds me to my trouble using Linux MIDI with external
equipment. There is jitter, that by theory isn't audible, but de facto
it's audible, at least for chamber music like jazz.
Indeed IMO there should be more real-time for MIDI real-time on Linux.
The same old 2 cents,
Ralf
PS: Why not programming for savant syndrome musical gifted and 'fast'
watching people too?
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