A quick and dirty script to transfer all PulseAudio streams between two sinks.

pulseaudio-switch.py

#!/usr/bin/env python

from argparse import ArgumentParser 

import json, os, re, subprocess

def main():
    parser = ArgumentParser()
    
    args = parser.parse_args()

    sinks = get_sinks()
    current_sink = None
    
    speaker_sink = None
    headphones_sink = None

    for sink in sinks:
        if sink.state == "RUNNING":
            current_sink = sink

        if sink.name == "alsa_output.pci-0000_00_1b.0.analog-stereo":
            speaker_sink = sink
        elif sink.name == "alsa_output.usb-Corsair_Vengeance_2000-00-V2000.iec958-stereo":
            headphones_sink = sink

    if current_sink == headphones_sink:
        # switch to headphones
        print "Redirecting audio to speakers."
        
        subprocess.call(["notify-send", "-i", "audio-card", 
            "Transferring audio playback to speakers.",
            "Audio playback has been transferred to the analog output speaker " +
            "system."])
        
        for stream in get_streams():
            move_stream(stream, speaker_sink)    
    else:
        # switch to the main speaker output
        print "Redirecting audio to headphones."
        
        subprocess.call(["notify-send", "-i", "audio-card",
            "Transferring audio playback to headphones.",
            "Audio playback has been transferred to the Corsair Vengeance 2000 " +
            "headset."])

        for stream in get_streams():
            move_stream(stream, headphones_sink)

def get_sinks():
    output = subprocess.check_output(["pactl", "list", "short", "sinks"])
    result = []

    for line in output.split("\n"):
        if re.match(r'\w', line):
            fields = re.split(r'\s+', line)
            result.append(PulseAudioSink(*fields))

    return result

def get_streams():
    output = subprocess.check_output(["pactl", "list", "short", "sink-inputs"])
    result = []
    
    for line in output.split("\n"):
        if re.match(r'\w', line):
            fields = re.split(r'\s+', line)
            result.append(PulseAudioStream(*fields))

    return result

def move_stream(stream, sink):
    return_code = subprocess.call(["pactl", "move-sink-input", str(stream.id),  str(sink.id)])
    if return_code != 0:
        raise Exception("Unable to transfer the stream: {}".format(return_code))

class PulseAudioSink:
    id = None
    name = None
    driver = None
    audio_format = None
    audio_channels = None
    audio_sample_rate = None
    state = None

    def __init__(self, id = None, name = None,
            driver = None, audio_format = None,
            audio_channels = None, audio_sample_rate = None,
            state = None):
        self.id = int(id)
        self.name = name
        self.driver = driver
        self.audio_format = audio_format
        self.audio_channels = re.match(r'(^\d+)ch', audio_channels).group(1)
        self.audio_sample_rate = re.match(r'(\d+)Hz', audio_sample_rate).group(1)
        self.state = state

class PulseAudioStream:
    id = None
    sink_id = None
    client_id = None
    driver = None
    audio_format = None
    audio_channels = None
    audio_sample_rate = None

    def __init__(self, id = None, sink_id = None,
            client_id = None, driver = None, audio_format = None,
            audio_channels = None, audio_sample_rate = None):
        self.id = id
        self.sink_id = sink_id
        self.client_id = client_id
        self.driver = driver
        self.audio_format = audio_format
        self.audio_channels = audio_channels
        self.audio_sample_rate = audio_sample_rate
    

if __name__ == "__main__":
    main()