voctocore/lib/audiomix.py



#!/usr/bin/python3
import logging
from gi.repository import Gst
from enum import Enum

from lib.config import Config

class AudioMix(object):
    log = logging.getLogger('AudioMix')

    mixingPipeline = None

    caps = None
    names = []

    selectedSource = 0

    def __init__(self):
        self.caps = Config.get('mix', 'audiocaps')

        self.names = Config.getlist('mix', 'sources')
        self.log.info('Configuring Mixer for %u Sources', len(self.names))

        pipeline = """
            audiomixer name=mix !
            {caps} !
            queue !
            tee name=tee

            tee. ! queue ! interaudiosink channel=audio_mix_out
        """.format(
            caps=self.caps
        )

        if Config.getboolean('previews', 'enabled'):
            pipeline += """
                tee. ! queue ! interaudiosink channel=audio_mix_preview
            """

        for idx, name in enumerate(self.names):
            pipeline += """
                interaudiosrc channel=audio_{name}_mixer !
                {caps} !
                mix.
            """.format(
                name=name,
                caps=self.caps
            )

        self.log.debug('Creating Mixing-Pipeline:\n%s', pipeline)
        self.mixingPipeline = Gst.parse_launch(pipeline)

        self.log.debug('Initializing Mixer-State')
        self.updateMixerState()

        self.log.debug('Launching Mixing-Pipeline')
        self.mixingPipeline.set_state(Gst.State.PLAYING)

    def updateMixerState(self):
        self.log.info('Updating Mixer-State')

        for idx, name in enumerate(self.names):
            volume = int(idx == self.selectedSource)

            self.log.debug('Setting Mixerpad %u to volume=%0.2f', idx, volume)
            mixerpad = self.mixingPipeline.get_by_name('mix').get_static_pad('sink_%u' % idx)
            mixerpad.set_property('volume', volume)

    def setAudioSource(self, source):
        self.selectedSource = source
        self.updateMixerState()