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Under consideration - OSC-support and how to ramp
Posted January 01, 2006 by Trond Lossius

Some notes on current discussions for further enhancements/changes to the core of Jamoma:

Alexander Refsum Jensenius has suggested that Jamoma syntax should align to Open Sound Control.

Based on experience from various projects last autumn, I’m feeling a need for some modifications and additions to how Jamoma is dealing with ramps. One of the problem is that ramps takes a lot of CPU. In one project I had to do changes instantaneously instead of by ramping simply because the ramps caused audio processing to stutter. Also when working on video/Jitter, it might make more sense to implement ramps in other ways that by the Max line object.

For this reason, if we can find a way of implementing it, I have suggested that we try to enhance the current implementation so that ramps can be performed in a number of different ways:

  • same way as line, timesteps should be setable
  • same way as bline. Number of bangs required should be setable
  • same way as my custom object
  • same way as qline
  • in the audio domain, same way as line~

If this is done in one or more custom externals, I believe that it could also be worthwhile to expand what kind of curves could be used for the ramp the same way as for my external that is attached.

One final addition that I forgot to mention at the jamoma-devel list is the ability to set what clock is used for ramping in Jamoma, so that it can be used for non-realtime rendering of video and audio.

Supposing that we are to implement open-sound-control syntax, here is a rough proposition for osc namespace for parameter/message subspace named param_name. I’m assuming that the parameter is of type msg_int or msg_float :

Change parameter:

/param_name [ int, float ] - instant change
/param_name [ list of two ints or floats ] - ramping to new value
/param_name [ list of multiple of 2 ints and floats ] - sequence of ramps, same way as for line~

Describing type:


Describing range:

/param_name/clip/range - [ list of two numbers ]
/param_name/clip/mode - [ none, low, high, both ]

Filter repetitions


Describing ramp:

/param_name/ramp/mode - [ none, signal, clock, nsteps (same as bline), systime (my approach), qelem ]
/param_name/ramp/curve - [ const, linear, cosine, tanh, exp_conv, exp_div, gauss, log(?) ]
/param_name/ramp/loop - [ boolean ]

/param_name/ramp [ stop, pause, resume ] - for controlling ramp

…we also need a syntax for setting timesteps for /mode clock and number of steps for /mode nsteps

Controlling the clock employed:



/param_name/doc [ string ]

Nothing is decided yet. It is all under consideration if and how to do it. I’ll try to add comments to this post as decisions are being made and new suggestions are raised.

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