How To Create A Virtual Audio Cable For Zoom In Linux Using Python And PulseAudio

Creating a virtual audio cable in Linux using Python involves manipulating the PulseAudio sound server to route audio between applications. Here’s a step-by-step tutorial on how to achieve this:

Step 1: Install Dependencies Make sure you have Python installed on your Linux system. Additionally, you’ll need to install the pyaudio and pulsectl Python packages. You can install them using the following command:

pip install pyaudio pulsectl

Step 2: Import Required Modules Create a new Python file and import the necessary modules:

import pyaudio
import pulsectl

Step 3: Create a PulseAudio Context Create a PulseAudio context object to interact with the sound server:

pa = pulsectl.Pulse('virtual-audio-cable')

Replace 'virtual-audio-cable' with a suitable name for your virtual audio cable.

Step 4: Find Source and Sink Devices Use the PulseAudio context to find the source and sink devices you want to use for audio routing. You can list all available devices using the following code snippet:

for source in pa.source_list():
    print(f"Source: {source.name}")
    
for sink in pa.sink_list():
    print(f"Sink: {sink.name}")

Identify the names of the source and sink devices you want to use and take note of them.

Step 5: Create a New Output Create a new output in PulseAudio using the selected source and sink devices:

source_name = 'YOUR_SOURCE_DEVICE_NAME'
sink_name = 'YOUR_SINK_DEVICE_NAME'

source = next(s for s in pa.source_list() if s.name == source_name)
sink = next(s for s in pa.sink_list() if s.name == sink_name)

pa.source_output_new(source, sink, stream_name='virtual-audio-output')

Replace 'YOUR_SOURCE_DEVICE_NAME' and 'YOUR_SINK_DEVICE_NAME' with the names of your chosen source and sink devices.

Step 6: Start Audio Stream Start the audio stream between the source and sink devices:

pa.event_listen()

Step 7: Cleanup and Termination To clean up and terminate the virtual audio cable, make sure to remove the created source output and close the PulseAudio context:

pa.source_output_remove(pa.source_output_list()[0].index)
pa.disconnect()

Expand this basic implementation to add features like volume control and dynamic routing

To add volume control and dynamic routing to the virtual audio cable implementation in Linux using Python, you can follow these steps:

Step 1: Import Additional Modules Import the necessary modules for volume control and dynamic routing:

import time
import sys

Step 2: Add Volume Control To implement volume control, you can use the pulsectl.PulseVolumeInfo object to get and set the volume level. Add the following code after creating the PulseAudio context:

volume_scale = 65536.0  # Adjust this value based on your system's volume scale

def get_volume():
    volume_info = pa.volume_get_all_chans(sink)
    return max(volume_info.values()) / volume_scale

def set_volume(volume):
    volume_value = int(volume * volume_scale)
    pa.volume_set_all_chans(sink, volume_value)

Step 3: Implement Dynamic Routing To enable dynamic routing, you’ll need to monitor changes in the available source and sink devices. Modify the pa.event_listen() line to include a loop that continuously checks for changes and updates the virtual audio cable accordingly:

while True:
    pa.event_listen()

    # Check if source or sink devices have changed
    source_changed = any(source.name == source_name for source in pa.source_list())
    sink_changed = any(sink.name == sink_name for sink in pa.sink_list())

    if source_changed or sink_changed:
        # Remove existing source output
        if pa.source_output_list():
            pa.source_output_remove(pa.source_output_list()[0].index)

        # Find new source and sink devices
        source = next(s for s in pa.source_list() if s.name == source_name)
        sink = next(s for s in pa.sink_list() if s.name == sink_name)

        # Create a new source output
        pa.source_output_new(source, sink, stream_name='virtual-audio-output')

    time.sleep(1)

Step 4: Test the Volume Control and Dynamic Routing You can now test the volume control and dynamic routing capabilities. Run the script, and you’ll have a virtual audio cable that dynamically adjusts itself when source or sink devices change. To control the volume, call set_volume() with a value between 0 and 1, and use get_volume() to retrieve the current volume level.

Remember to replace 'YOUR_SOURCE_DEVICE_NAME' and 'YOUR_SINK_DEVICE_NAME' with the names of your desired source and sink devices.

This expanded implementation allows you to adjust the volume and automatically reroute the audio stream based on changes in the available devices. You can further customize and extend the code to suit your specific requirements or add additional features as needed.

Connect the virtual audio cable to zoom

To connect the virtual audio cable you created to Zoom, follow these steps:

Step 1: Open Zoom Audio Settings Launch Zoom and navigate to the audio settings. You can access the audio settings by clicking on the arrow next to the microphone icon in the bottom left corner of the Zoom window and selecting “Audio Settings.”

Step 2: Select the Virtual Audio Cable as the Microphone In the audio settings, under the “Microphone” section, select the virtual audio cable as the input device. The virtual audio cable should be listed as an available input device, typically with the name you specified during the virtual audio cable creation.

Step 3: Test the Audio To ensure that the virtual audio cable is correctly connected to Zoom, you can test the audio. Speak into your microphone or play some audio, and you should see the microphone level indicator moving in the Zoom audio settings.

Step 4: Adjust the Volume If necessary, adjust the volume of the virtual audio cable in the PulseAudio context using the set_volume() function we implemented earlier. You can set the volume to an appropriate level based on your requirements.

Step 5: Start or Join a Zoom Meeting Once the virtual audio cable is connected and the volume is adjusted, you can start or join a Zoom meeting as usual. The audio from the selected source device will be routed through the virtual audio cable and transmitted to Zoom.

That’s it! You have successfully connected the virtual audio cable to Zoom. Now, any audio coming from the selected source device will be captured by the virtual audio cable and used as the microphone input in Zoom.