[gst-devel] volume plugin

[Baker, Steve]

I've just done a quick survey of media player volume slider behaviour and
here is the verdict:

Smooth volume changes:
-winamp
-real player
-windows media player

Jerky volume changes:
-Quicktime player for windows
-XMMS
-gst-player

By the sound of it I don't think the smooth players actually use a smoothing
algorithm, I think they just use small buffer sizes for the volume stage -
its hard to tell though.

The graphic EQ in winamp seems to use a huge buffer, but its sliders are
also very smooth.  When rhythmbox gets a graphic EQ it will probably need
smooth sliders because IIR filter coefficients could easily become unstable
if filter parameters change too quickly (presuming of course that an IIR
filter is used).

cheers

> -----Original Message-----
> From: Baker, Steve [mailto:SBaker at CHELLO.com]
> Sent: maandag 6 mei 2002 8:20
> To: 'gstreamer-devel at lists.sourceforge.net'
> Subject: RE: [gst-devel] volume plugin
> 
> 
> DParams are designed so that if you don't want to use them in 
> your app you
> don't have to.
> 
> Company committed a small fix to the volume plugin which was 
> preventing it
> from working in gst-player - this might fix the problem with rb.
> 
> The other change is that the muted property has been renamed 
> to "mute" (but
> jorn knows this because I told him ;)
> 
> So if volume is broken, its not because of dparams - its 
> because I broke it.
> Bug reports welcome.
> 
> Having said all that, now that volume used dparams we could 
> use dparams in
> gst-player and rb.  The only benefit to doing this would be 
> to allow smooth
> volume changing.  At the moment if you drag the volume slider 
> the volume
> will change jerkily and you will hear audible artifacts like 
> clicks. Using
> the smoothing dparam will make volume changes just gradual 
> enough to avoid
> artifacts.
> 
> Extra memory usage would be minimal since the gstcontrol 
> library is already
> loaded for volume.
> 
> So I would like some opinions. If anyone has serious 
> objections to having
> dparams in consumer apps I will pursue this no further.  
> Otherwise I was
> planning on adding dparams to gst-player as a demo.
> 
> cheers
> 
> > -----Original Message-----
> > From: Thomas Vander Stichele [mailto:thomas at urgent.rug.ac.be]
> > Sent: 05 May 2002 22:22
> > To: gstreamer-devel at lists.sourceforge.net
> > Subject: [gst-devel] volume plugin
> > 
> > 
> > Hi,
> > 
> > This is actually for steve but I'm too lazy so I throw it up 
> > for general 
> > discussion ;)
> > 
> > THe volume plugin has been changed to use dparams.  While I 
> > like dparams, 
> > jorn of rhythmbox asked me what's up with the plugin because 
> > obviously it 
> > doesn't work for them anymore.
> > 
> > So the question - should volume really have dparams ? How can 
> > they get the 
> > old functionality with the current dparams ? ...
> > 
> > Thomas

>