Live broadcasting

This page explains how to broadcast live audio through BotWave, meaning audio streamed in real time rather than from a pre-recorded file.

Note

This page assumes you're already familiar with the basics. If not, start with Main/Basic Usage.

How it works

Live broadcasting in BotWave uses an ALSA loopback card. It is a virtual audio device on your system that acts as a bridge. You send audio into it from any application, and BotWave picks it up and transmits it over FM. Think of it like a virtual cable between your audio source and the radio transmitter.

Important

You need the ALSA loopback card installed for live broadcasting to work. If you skipped it during installation, you can enable it by re-running the installer with the --alsa flag:

curl -sSL https://botwave.dpip.lol/install | sudo bash -s -- client --alsa

Then verify it's available by running aplay -l — you should see two BotWave cards listed.

Starting a Live Broadcast

Once your ALSA card is set up, starting a live broadcast is straightforward. In your BotWave prompt, type live:

Local Client:

botwave> live [frequency] [ps] [rt] [pi]

Server:

botwave> live <targets> [frequency] [ps] [rt] [pi]

Parameter	Description
targets	(server only) Client ID, hostname, or all
frequency	FM frequency in MHz (default: 90.0)
ps	Station name shown on RDS radios (default: BotWave)
rt	Station description (default: Broadcasting)
pi	Program Identifier code (default: FFFF)

Example:

botwave> live 88.5 MyRadio "Live Show"

Once the command runs, BotWave is listening on the ALSA loopback card. Now you just need to send audio to it.

Sending Audio to BotWave

The ALSA card expects audio in this format: 48000 Hz, 2 channels, S16_LE. Any source that can output in this format will work.

Playing a local file

This is useful for streaming files to clients without storing them on their filesystem first:

aplay -D plughw:BotWave,0 yourfile.wav

Using a microphone

1. Find your microphone's card name:

   arecord -l

2. Pipe its audio into BotWave:

   arecord -D plughw:YOUR_CARD,0 -f S16_LE -c 2 -r 48000 | aplay -D plughw:BotWave,0

   Replace YOUR_CARD with your microphone's card name or number from the previous step.

Streaming from Another Device

This section covers how to stream audio from a separate computer to the Pi running BotWave. Both machines need FFmpeg installed.

From a Linux or Mac computer

On the Pi, start listening for incoming audio:

ffmpeg -f s16le -ac 2 -ar 48000 -i udp://0.0.0.0:5004 -f alsa plughw:BotWave,0

On your Linux or Mac computer, send audio from your system output. First find your output device:

# Linux (PulseAudio)
pactl list short sources

# Mac
ffmpeg -list_devices true -f avfoundation -i dummy

Then stream it:

# Linux (PulseAudio) - replace with your source name
ffmpeg -f pulse -i your_monitor_source -ac 2 -ar 48000 -f s16le udp://PI_HOST:5004

# Mac - replace with your device index
ffmpeg -f avfoundation -i ":DEVICE_INDEX" -ac 2 -ar 48000 -f s16le udp://PI_HOST:5004

Replace PI_HOST with your Pi's IP address.

From a Windows computer

This uses VoiceMeeter to capture your system audio and FFmpeg to stream it.

Windows setup

1. Install VoiceMeeter
2. Open VoiceMeeter and in the VIRTUAL INPUT section:
   • Disable the >A button
   • Enable the >B button
3. Set your system audio output to VoiceMeeter Input (VB-Audio Voicemeeter VAIO)
4. Verify FFmpeg can see it:

   ffmpeg -list_devices true -f dshow -i dummy

   You should see Voicemeeter Out B1 (VB-Audio Voicemeeter VAIO) in the list.

Pi setup

On the Pi, start listening:

ffmpeg -f s16le -ac 2 -ar 48000 -i udp://0.0.0.0:5004 -f alsa plughw:BotWave,0

Stream from Windows

ffmpeg -f dshow -i audio="Voicemeeter Out B1 (VB-Audio Voicemeeter VAIO)" -ac 2 -ar 48000 -f s16le udp://PI_HOST:5004

Replace PI_HOST with your Pi's IP address.

Expect around 5 seconds of latency depending on your network. The transmission speed should stabilize around 1x after a few seconds. If it doesn't, restart both FFmpeg commands.

Troubleshooting

The live command fails or nothing transmits:

• Run aplay -l and confirm a BotWave card is listed. If not, re-run the installer with --alsa.

Audio is silent or cuts out:

• Make sure your source is outputting at 48000 Hz, 2 channels, S16_LE. Mismatched formats are the most common cause of silence.

FFmpeg stream is too fast or too slow:

• Restart both FFmpeg commands (Pi side first, then computer side). This usually stabilizes within a few seconds.

Still stuck? Check the FAQ or open an issue here.