[OSC_dev] OSC / MIDI comparison papers

[Andy W. Schmeder]

On Jan 15, 2008, at 3:26 PM, cyrille henry wrote:

> /wii/ir/x....,f......
> where . is not a letter/number
> so i don't think it's "human readable"

The OSC address and typetag sections are null-terminated strings of  
printable ASCII characters -- therefore, human readable.  However the  
data section is binary, unlike e.g., XML which is entirely human  
readable.

MIDI is entirely a binary format -- it has no readable component  
anywhere.


> -The "Hardware Transport Independent" is in direct conflict with  
> "Data rate":
> osc is hardware transport independant, so we can use osc with a  
> 9,6Kb/s serial line.

MIDI has a defined hardware transport, OSC does not, so a direct  
comparison isn't really possible.  The limits are therefore given for  
the typical case which is MIDI cable vs ethernet.

The limits may not apply to MIDI when it is used in a pure software  
context or over alternative transports (e.g. RTP-MIDI and possibly  
some USB MIDI devices).


> -Curent OSC transport layer is not really microcontroller friendly.
> few dollars microcontroller can easilly deal with midi, but not  
> with curent osc implementation.
> a osc implementation on a microcontroler is lots more difficul than  
> midi.

More difficult perhaps, but in actuality, not by much.  There are  
several implementations of OSC on microcontrollers.

I would argue that such implementations are in fact easier to work  
with.  For what its worth, I've written one of those implementations  
myself (not released yet), so I should know.


> -where does the 20ms midi clock-sync accuracy theorical limit?

I can't remember... actually I think it may be wrong as a theoretical  
limit.

At the very least, that should read "clock precision" not "clock sync  
accuracy".

At a nominal rate of 120 BPM the MIDI beat clock has a precision of  
20msec.


> -this chart does not speak about the osc typetag : when  
> implementing a osc recever, why you have to test for float or int  
> if you wish to receive 0?

Zero is the same bit pattern in both floating point and integer.   
Perhaps don't understand your question...?


Thank you for the comments--
Andy.


---

Andy W. Schmeder
andy [at] cnmat.berkeley.edu
phone:	+1-510-643-9990 x.313

Programmer/Analyst II
Center for New Music and Audio Technologies
University of California at Berkeley
http://cnmat.berkeley.edu

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