Phonon VolumeFaderEffect not working with VLC backend

[David Jarvie]

On Sunday, 1 May 2022 00:23:30 BST Harald Sitter wrote:
> Unfortunately VolumeFaderEffect is presently not supported by VLC

Is it possible to determine programmatically whether the current backend 
supports VolumeFaderEffect? I looked at the output from 
BackendCapabilities::availableAudioEffects(), and for GStreamer it returns 
names and descriptions:

"equalizer-10bands",  desc: "Direct Form 10 band IIR equalizer"
"KEqualizer",  desc: "Compatibility effect. Do not use in new software!"
"audiopanorama",  desc: "Positions audio streams in the stereo panorama"
"audioamplify",  desc: "Amplifies an audio stream by a given factor"
"audiodynamic",  desc: "Compressor and Expander"

None of these is (to me) obviously related to VolumeFaderEffect. For VLC, only 
the first one is returned, "equalizer-10bands".

-- 
David Jarvie.
KDE developer, KAlarm author.