[LAD] audio/midi app development

[Ralf Mardorf]

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 <james at 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?