tskir/bluetooth-sync

bluetooth-sync

Configure

python3 -m pip install --user audio-offset-finder

• To get the microphone: pacmd list-sources | egrep '^\s+name: .*alsa_input'.
• To get the output: pacmd list-sinks | egrep '^\s+name: .*alsa_output'.
• To get the port: look into pacmd list-sinks for your output.

Run

# Desktop for testing
export MICROPHONE=alsa_input.usb-046d_0825_07B43310-02.mono-fallback
export OUTPUT=alsa_output.pci-0000_08_00.1.hdmi-stereo-extra2
export PORT=hdmi-output-2

# Laptop + projector
export MICROPHONE=alsa_input.pci-0000_00_1f.3.analog-stereo
export OUTPUT=bluez_sink.00_22_6C_0A_18_E2.a2dp_sink
export PORT=speaker-output
export CARD=bluez_card.00_22_6C_0A_18_E2

###########

# Desktop + projector
export MICROPHONE=alsa_input.usb-046d_0825_07B43310-02.mono-fallback
export OUTPUT=bluez_sink.00_22_6C_0A_18_E2.a2dp_sink
export PORT=speaker-output
export CARD=bluez_card.00_22_6C_0A_18_E2

export MONITOR="${OUTPUT}.monitor"
while true; do
  rm -f /tmp/microphone.wav /tmp/monitor.wav
  sleep 2
  timeout 10 parecord --channels=1 -d $MONITOR /tmp/monitor.wav &
  sleep 3
  timeout 24 parecord --channels=1 -d $MICROPHONE /tmp/microphone.wav
  wait
  export CURRENT_LATENCY_USEC=$(pacmd list-sinks | grep "${PORT}:" | cut -d '(' -f2 | cut -d ' ' -f5)
  export REQUIRED_LATENCY_USEC=$(python3 -c "from audio_offset_finder.audio_offset_finder import find_offset_between_files; print(int(find_offset_between_files('/tmp/microphone.wav', '/tmp/monitor.wav')['time_offset']*1000000+3000000))")
  echo "Current latency is ${CURRENT_LATENCY_USEC}. Required latency is ${REQUIRED_LATENCY_USEC}."
  if ((REQUIRED_LATENCY_USEC >= 0 && REQUIRED_LATENCY_USEC <= 1000000)); then
    pacmd set-port-latency-offset ${CARD} ${PORT} ${REQUIRED_LATENCY_USEC}  
  else
    echo "Required latency out of range: ${REQUIRED_LATENCY_USEC}"
  fi
done