Open Sound Control. OSC is a packet-based protocol for communication between devices. The protocol lies part way between XML and binary formatted protocols. It is self describing and fairly efficient.

Each OSC message has three distinct sections:

address type-tag data

The address is a URI-like string describing the data location - for example "/led/state". The type-tag is a string, beginning with a comma that encodes the data to follow - for example ",i". What follows are 4 byte big endian integers, 4 byte floating point numbers, strings or blobs as specified in the type tag. All strings and blobs - including the address and type-tag are all padded to 4 byte boundaries.

Tools like MC Helper convert text to properly formed OSC messages, permitting the user to type:

"/led/state 1"

which gets translated into the OSC message

             "/led/state" ",i" 1

which in numerical form would look like the following:

0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19
'/'	'l'	'e'	'd'	'/'	's'	't'	'a'	't'	'e'	0	0	','	'i'	0	0	0	0	0	1

An incoming OSC messages is subjected to the reverse process.

More than one message may be bundeld up into one packet using some additional codes.

For more information check the OSC tutorial.