[gst-devel] proposal for implementing dynamic parameters

Steve Baker sbaker at chello.com
Thu May 10 16:42:39 CEST 2001

> On Tue, May 08, 2001 at 08:42:23PM +0200, Steve Baker wrote:
> > I have written a wiki page which outlines my thoughts on how we can
> > implement dynamic parameters in GStreamer.
> > 
> > Feel free to check it out and make any comments:
> > http://gstreamer.net/wiki/GstDynamicParams
> This functionality is important to implement, and I really hope there
> is time to do it before 0.2.0 is out :)

It would be nice but I don't think we should aim to get this in 0.2.0.
Mainly because it hasn't even been started yet, but also because 0.2.0
should probably just be a solidification of current features.

> However, I have one question. How do you, as an 
> applications-developer,
> send this control-data? Are you supposed to provide GStreamer with an
> array of control-data to send along at specified intervals, or are
> signals used? Signals introduce some overhead, so they might not be
> the optimal sollution. I didn't read anything about this, ir was I
> reading too fast?

Neither really.  Applications will deal with a relatively high-level API and
will build control data by setting attributes on instances of dparams, and
setting control points which will eventually be interpolated into control
data in the plugins.

A simplified application sequence might be
- get instances of dparams from plugin instance
- set interpolators on each dparam to create desired behaviour
- user sets control points (probably x y values) to build the time-response
- run the pipeline

and hey presto!

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