pulse_record.py

import pulsectl  # pip install pulsectl==18.12.5
import time


#                      (other apps) -----------------------+
#                                                          |
#                                                          v
# microphone --> call --> pr-out -- mon --> loopback --> speakers
#          |                        |
#          |                        v
#          |                 loopback
#          |                 |
#          v                 v
#          loopback -> pr-rec -- mon --> recorder


def main():
    with pulsectl.Pulse('pulse-record') as pulse:
        cleanup = []

        try:
            # Locate default source/sink
            mic = pulse.server_info().default_source_name
            mic, = [source
                    for source in pulse.source_list()
                    if source.name == mic]
            speakers = pulse.server_info().default_sink_name
            speakers, = [sink
                         for sink in pulse.sink_list()
                         if sink.name == speakers]

            # Build node for call output
            output_mod = pulse.module_load('module-null-sink', args='sink_properties=device.description=pr-out')
            cleanup.append(output_mod)
            time.sleep(0.5)
            output, = [sink
                       for sink in pulse.sink_list()
                       if sink.owner_module == output_mod]
            output_monitor, = [source
                               for source in pulse.source_list()
                               if source.name == output.monitor_source_name]

            # Build node for call output + mic, for recording
            record_mod = pulse.module_load('module-null-sink', args='sink_properties=device.description=pr-rec')
            cleanup.append(record_mod)
            time.sleep(0.5)
            record, =  [sink
                        for sink in pulse.sink_list()
                        if sink.owner_module == record_mod]
            record_monitor, = [source
                              for source in pulse.source_list()
                              if source.name == record.monitor_source_name]

            # Send call output to speakers
            lb = pulse.module_load(
                'module-loopback',
                'source=%s sink=%s latency_msec=1' % (output_monitor.name, speakers.name),
            )
            cleanup.append(lb)

            # Restore defaults
            pulse.sink_default_set(speakers)
            pulse.source_default_set(mic)

            # Send mic and call output to recording node
            lb = pulse.module_load(
                'module-loopback',
                'source=%s sink=%s latency_msec=1' % (mic.name, record.name),
            )
            cleanup.append(lb)
            lb = pulse.module_load(
                'module-loopback',
                'source=%s sink=%s latency_msec=1' % (output_monitor.name, record.name),
            )
            cleanup.append(lb)

            print("Devices created")

            # Now we wait for call to show up, to connect it to 'output'
            # Also wait for audacity, to connect it to 'record_monitor'
            audacity_found = False
            calls = set()

            while True:
                if not audacity_found:
                    # Find audacity, route from 'record_monitor', set audacity_found
                    for rec in pulse.source_output_list():
                        app = rec.proplist.get('application.name')
                        if app and 'audacity' in app:
                            print("Audacity found, wiring it up: %s" % app)
                            pulse.source_output_move(rec.index, record_monitor.index)
                            audacity_found = True

                # Find calls, route to 'output'
                for out in pulse.sink_input_list():
                    if out.index in calls:
                        continue
                    app = out.proplist.get('application.name')
                    if app in (
                            'WEBRTC VoiceEngine',  # Zoom
                            'Chrome', 'Chromium', 'Google Chrome',
                            'Skype',
                    ):
                        print("Call identified, recording: %s" % app)
                        pulse.sink_input_move(out.index, output.index)
                        calls.add(out.index)

                # Remove terminated calls from list
                calls.intersection_update(
                    out.index
                    for out in pulse.sink_input_list()
                )

                time.sleep(2)
        except KeyboardInterrupt:
            pass
        finally:
            print("Cleaning up")
            for mod in reversed(cleanup):
                pulse.module_unload(mod)


if __name__ == '__main__':
    main()