LightStripAudioSync

LightStripAudioSync is a simple Windows tool that analyzes the audio stream of your default audio device. It automatically discovers compatible devices on your network and sends them audio-channel-dependent magnitudes, i.e., for displaying a peakmeter. An example config for making esphome devices compatible is shown in section Integrating with esphome. The auto-discovery process is explained in the section Device discovery.

LightStripAudioSync is based on FFTW3 and RtAudio.

Installation

1. Clone the repository via git clone https://github.com/itzFlubby/LightStripAudioSync.git

2. Clone the submodules via git submodule update --init --recursive

3. Download the precompiled FFTW DLLs from the FFTW website:

   • Copy fftw3.h, libfftw3-3.dll, and, libfftw3-3.def into the FFTW directory.
   • Generate the libfftw3-3.lib with MSVC lib.exe /def:libfftw3-3.def in the FFTW directory. Hint: The usual install path is C:\Program Files\Microsoft Visual Studio\XX\Community\VC\Tools\MSVC\XX.XX.XXXXX\bin\Hostx64\x64\lib.exe

4. Optional: configure for your use-case

   • Set frequency weights in AudioCapture.cpp
   • Set MAX_FREQUENCY and BINS_SIZE in AudioCapture.hpp

5. Run Cmake via build.bat

Hint: if cmake .. fails, check cmake -G and try building with a specific generator.

6. Run LightStripAudioSync.exe

Device discovery

The general protocol is defined as follows:

<STX><TYPE><LEN><DATA><ETX>

i.e.

Discover packet: 0x02 0x00 0x00 0x03
Register packet: 0x02 0x01 0x00 0x03
Data packet:     0x02 0x02 0x02 0x31 0x2f 0x03

For discovering devices, LightStripAudioSync.exe sends a discovery packet as a broadcast UDP packet every five seconds on port 3333. Compatible devices on your network must respond to the broadcast with a registration packet on the same port. LightStripAudioSync.exe will then start sending the device the magnitudes of the audio stream on your default audio device every ~30ms. <LEN> will be the number of channels of your default audio device, and <DATA> the respective magnitudes for each channel.

Integrating with esphome

Example config:

esphome:
  name: lightstripaudiosync
  friendly_name: "LightStripAudioSync"
  
  includes:
    - LightStripAudioSync/Packet.hpp

globals:
  - id: magnitudes
    type: uint8_t[2]
    restore_value: no
    initial_value: "{ 0, 0 }"

udp:
  - id: lightstrip_audiosync_listener
    port : 3333
    on_receive:
      then:
        - if:
            condition:
              lambda: |-
                Packet packet(reinterpret_cast<const char*>(data.data()), data.size());
                return packet.is_valid() && packet.is_discover();
            then:
              - udp.write:
                  id: lightstrip_audiosync_listener
                  data: !lambda |-
                    Packet packet(Packet::destination_t::broadcast, Packet::type_t::register_, 0, 0); 
                    return packet.to_raw();
                    
        - lambda: |-
            Packet packet(reinterpret_cast<const char*>(data.data()), data.size());
            if (packet.is_valid() && packet.is_data()) {
              if (packet.get_payload_size() == 2) {
                memcpy(id(magnitudes), packet.get_payload(), packet.get_payload_size());
              }
            }