[PD-dev] PD-cvs Digest, Vol 29, Issue 11

[Martin Peach]

IOhannes m zmoelnig wrote:
> pd-cvs-request at iem.at wrote:
>   
>> Message: 6
>> Date: Wed, 11 Jul 2007 17:34:40 +0000
>> From: Martin Peach <mrpeach at users.sourceforge.net>
>> Subject: [PD-cvs] externals/mrpeach/osc packOSC-help.pd, 1.6, 1.7
>> 	packOSC.c,	1.6, 1.7 unpackOSC.c, 1.3, 1.4 routeOSC-help.pd, 1.2, 1.3
>> To: pd-cvs at iem.at
>> Message-ID: <mailman.9.1184234402.17743.pd-cvs at iem.at>
>>
>> Update of /cvsroot/pure-data/externals/mrpeach/osc
>> In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv5352
>>
>> Modified Files:
>> 	packOSC-help.pd packOSC.c unpackOSC.c routeOSC-help.pd 
>> Log Message:
>> unpackOSC now simply outputs (through the right outlet) a delay in milliseconds when it 
>> receives a timetag, as the timetag itself is not useable inside pd.
>> The delay is zero when the timetag is in the past.
>> Help patches have been updated to match.
>> Also corrected a mistake in packOSC.c timetag calculation.
>>     
>
>
> cool feature, thanks martin.
>
> however, i have 2 remarks:
>
> the simple one:
> is it possible to set the "current" timetag within the [packOSC] and the
> [unpackOSC]? usually 2 osc-hosts should be synchronized via ntp, but who
> knows...
> otoh, this might be rather low priority...
>
>   
You can set the offset in packOSC so you can send a packet from the 
future as it were ;) I think that setting the actual time should be done 
outside of pd.

>
> the more complicated one:
>
> "0" for past events is (imho) not a very good choice.
> how should we distinguish between bundles that have just arrived "in
> time" (where the natural delay is "0"), bundles that are tagged
> "immediately", and bundles that arrived too late.
>
> one solution might be to use negative delays: delaying objects, such as
> [delay] and [pipe] just ignore negative values (so they behave the same
> as when fed with "0"), but the user has the option to determine whether
> the message arrived to late and can act accordingly (e.g. discard
> messages that should have happened yesterday)
>
>   
OK, I'll put in negative delays.

> i haven't looked at the code, but what happens when a bundle is to be
> processed "immediately": a delay of "0" is _not_ the same as no delay,
> as can be seen in:
>
> [bng]
> |
> [trigger bang bang bang]
> |           |          [print c]
> [print a]   |
>             [del 0]
>             |
>             [print b]
>
> which will result in "c, a, b"
>
>
> so if i am to honour the timetags (via [del] or whatever), my
> "immediate" messages will not be handled immediately (it sounds worse
> than it is: due to the nature of network traffic, we could always assume
> that the "immediate" bundle arrived a fraction of a second later...;
> nevertheless i think it might be very good if i could distinguish
> between the 3 "types" of timetags)
>
>   
That's a difficult problem. What's the difference between zero and zero? 
I mean how does one tag no delay as being different from a delay of zero 
without adding another outlet?
There's a problem with unpackOSC at the moment in that if no time tag is 
received there is no output on the second outlet, so you have to 
externally zero the delay line after every message.

Martin

> mfg.asdr
> IOhannes
>
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