Plugin design

Audio Test Source

• based on code in sine (sinesrc)
• new properties
  • waveform = { silence, sine, saw, srq, noise }

now available in gstreamer cvs ;)

Simple Synth

Simple 1 osczillator synthesizer based on audiotestsrc. (gstsimsyn in gst-buzztard cvs)

properties

• note (trigger)
• volume
• length (note-length)
• filter
  • filter-type
  • cutoff
• envelope
  • attack-time
  • decay-time
  • sustain-level
  • release-time

algorithm

Note is the trigger param. It restarts the envelopes by setting the tone-time to 0.

envelope generator

The idea is that we build have a internal envelope object. The control-value property is managed by gstreamer-controller. When the envelope properties of the gstreamer-element change, they affect the control-points of the envelope object.

The gst-element needs to implement the tempo iface if we allow envelope-segment times to be specified as tick-times.

filter

Use a state variable filter. That would add three parameters

• filter-type = { low-pass, high-pass, band-pass, notch }
• cut-off frequency
• resonance

variants

Have a polyphonic version. Have a version with multiple osczillators.

Panorama

Stereo

• accept mono/stereo
  • mix stereo to mono first, or do balance for stereo input
    • pan moves data hard left right,
    • balance for stereo would balance the stereo image (ctrl -100: left unchanged, right->left, ctrl 0: left,right unchanged, ctrl 100: left->right, right unhanged)
• output stereo
• parameter : pan-lr

Quadro

• accept mono/stereo/multi-channel
  • mix multiple to mono before
• output quadro (mapping?)
• parameter : pan-lr, pan-fr