[LAU] Open Sound Control: Is it still a thing?
ritsch at iem.at
Mon May 3 21:39:15 CEST 2021
Am Montag, 3. Mai 2021, 11:48:07 CEST schrieb Fons Adriaensen:
> On Sun, May 02, 2021 at 09:37:40PM +0200, Winfried Ritsch wrote:
> > Please disagree if you can reference:
> > - OSC 1.0 ist not only UPD
> In theory this is true, but if you use any transport that does not
> provide message boundaries, you need close integration of the data
> receiving code and the actual parsing of the OSC message. This is
> because you don't know where in a stream of bytes for a message
> ends until you have at least parsed the path and the format string.
> So you can't just 'wait for a message' without interpreting it and
> then only when it is complete pass it to a decoder.
> If the transport is just a stream of bytes, you *could* wait
> until no more data is received for some time and assume that the
> message is then complete, and pass it to a decoder. This will of
> course introduce delay, and it could easily fail.
> Now UDP is the only common transport that *does* provide message
> boundaries, so probably that's why it is said that you need UDP.
On the other side, with the type tags, you know when a message is complete if
you wait for number of bytes or the the type ends(, if no bytes got lost...)
The problem of UDP: UDP applications must be willing to accept some packet
loss or this has to be handled by the protocol implemented with OSC. and/or it
should be a "stateless" protocol.
So if package loss is a problem, think of a mute action TCP/IP is more easy to
handle, since we know when a connection is lost.
So maybe its better to do stream parsing and a stream protocol than UDP and
some handshake or failsave protocol, but of course this depends on the use
case, so on a sound system critical mixer I prefer TCP/IP.
> > - OSC was not a intended to replace MIDI,
> > - OSC predecessor was ZIPI not MIDI
> True, sort of.
- ao.Univ.Prof. DI Winfried Ritsch
- ritsch at iem.at - http://iem.at/ritsch
- Institut fuer Elektronische Musik und Akustik
- University of Music and Dramatic Art Graz
- Tel. ++43-316-389-3510 (3170) Fax ++43-316-389-3171
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