Morse Code Audio over Mumble: alsa-loopback to interject a CW AUDIO bandpass filter for mumble input

[Chuck aa0hw]

snd-aloop

alsa-loopback cable

virtual audio cable

via a Gstreamer TEE SCRIPT to take a keyed oscillator at the mumble sound card input... filter it 1st... and then send it to two places...

1. the mumble USB sound card's output so you can monitor your own 'filtered' sidetone

2. the mumble USB sound card input so others can hear your 'filtered sidetone'

this setup uses a TEE ELEMENT in Gstreamer to create a Gstreamer Bandpass Audio Filter Script and send the final CW AUDIO filtered sidetone to TWO DESTINATIONs

- soundcard output for sidetone monitoring

- mumble input

NOTE: PAVUCONTROL must be used to select which ALSA-LOOPBACK to use via PAVULCONTROL's PLAYBACK TAB and RECORDING TAB on the PAVUCONTROL's GUI

Here is the Gstreamer script used in this video demo:

gst-launch-1.0 -v alsasrc device=hw:4 ! audio/x-raw, channels=1, format=S16LE, layout=interleaved, rate=48000 ! tee name=t t. ! queue ! audioconvert ! audiowsincband mode=band-pass lower-frequency=580 upper-frequency=820 length=384 window=3 low-latency=true ! audioconvert ! pulsesink buffer-time=10000 sync=false async=false t. ! queue ! audioconvert ! audiowsincband mode=band-pass lower-frequency=580 upper-frequency=820 length=384 window=3 low-latency=true ! audioconvert ! pulsesink buffer-time=10000 sync=false async=false NOTE: alsasrc device=hw:4 is Mumble's USB sound card's INPUT