bardcast is a commandline application that can read audio playing on your system and stream it to a Discord voice chat. Currently, only Unix-like systems running PulseAudio are supported, although support for other OSes and sound servers may be added in the future.

The PulseAudio driver is not currently compatible with PipeWire's compatibility layer. For more information, please see issue #9. Native PipeWire support is being tracked in issue #4.

Building

bardcast needs the following libraries available on your system:

• libopus (via Songbird)
• Linux only
  • libpulse (if using the default pulse feature for PulseAudio support)
    • Debian/Ubuntu: libpulse-dev
    • Fedora: pulseaudio-libs-devel
    • openSUSE: libpulse-devel
    • Arch: libpulse

Once these dependencies are installed, simply run cargo build -r to create a release build of bardcast.

Each audio driver has its own feature flag; the most common servers are enabled by default, but can be disabled by passing --no-default-features to cargo and manually specifying the drivers you want.

The minimum supported Rust version for this project is 1.70.0. This will be updated on an as-needed basis.

Setup

Unlike most Discord bots, there is no quick link to add bardcast to your server -- because bardcast runs on your machine (rather than on a server), you must generate your own bot user and token to use it.

To create your own bot user, visit the Discord developer portal and create a new application. Disable the "Public Bot" option in the Bot settings (since you will have sole control over the bot), generate a token for the bot user (using the "Reset Token" button on the Bot page), and store it in a safe place. This token can be used with bardcast's -t command line option, or the token option in the discord section of a configuration file.

When generating an OAuth2 invite URL (Application settings > OAuth2 > URL Generator), ensure the following options are checked:

• Scopes
  • bot
• Bot permissions
  • General permissions
    • Read messages/view channels
  • Text permissions
    • Send messages
  • Voice permissions
    • Connect
    • Speak
    • Use Voice Activity

Visit the generated URL in a browser that is logged into your Discord account to invite the bot to any server where you have rights to invite bots.

Usage

bardcast needs, at a minimum, a bot token, a server ID, and a voice channel name in order to connect and start playing audio. The server ID can be found by enabling developer mode in Discord and using the "copy server ID" option in the context menu for the server, or by using the --list-servers option:

bardcast -t $BOT_TOKEN_HERE --list-servers

Note: Be careful not to leak your bot token into your shell history when using -t/--token -- use an environment variable or a commandline password manager like pass.

Once you have the server, specify the ID and name of the voice chat to connect to:

bardcast -t $BOT_TOKEN_HERE -s $SERVER_ID --voice-channel $VOICE_CHANNEL

bardcast also supports different intercept modes, which determine how system audio is captured and can be specified with -m. The default depends on the driver; some modes that focus on capturing individual applications may require that you specify a regular expression to match applications against with -E:

bardcast -t $BOT_TOKEN_HERE -s $SERVER_ID --voice-channel $VOICE_CHANNEL -m peek -E vlc

Most of bardcast's command line arguments can also be specified through an INI-format configuration file with -c:

bardcast -c $CONFIG_FILE

Fore more commandline options, see -h/--help.

Configuration file options

All configuration options will be overridden by their corresponding command line argument, if both are present.

Section: bardcast

General top-level application configuration.

Option	Type	Description
log-level	off, error, warn, info, debug, trace	Specifies the level of verbosity produced by the application. Defaults to info.
driver	pulse	The name of the sound driver to use. Some drivers may be unavailable, depending on your OS.
stream-timeout-ms	u64	The number of elapsed milliseconds between audio chunks before bardcast considers the stream stale and stops sending audio. Defaults to 250.
threads	usize	The number of worker threads to spin up for the application. This does not include the application main thread or threads spun up internally by libraries. Defaults to 2.

Section: discord

Configuration options for the discord client.

Option	Type	Description
token	String	The Discord API token to use.
server-id	u64	The numeric ID of the Discord server to connect to.
voice-channel	String	The name of the voice channel to connect to.
metadata-channel	String	The name of the text channel to post event messages to.

Section: pulse

Configuration options for the PulseAudio sound driver. This driver is only available on Unix systems when built with the pulse feature flag.

Option	Type	Description
intercept-limit	usize	A limit to the number of streams that bardcast intercepts concurrently. No limit will be applied if not set.
intercept-mode	capture, monitor	The audio intercept mode that the driver should use. Defaults to capture.
stream-regex	Regular expression	A regular expression that matches against applications that you want to intercept.
stream-properties	Comma-separated list	A list of PulseAudio property names to match stream-regex against.
server	String	The path to the PulseAudio server.
sink-name	String	The name of the audio sink to use with the monitor intercept mode.
sink-index	u32	The index of the audio sink to use with the monitor intercept mode. Overrides sink-name if both are set (unless sink-name is provided as a command line argument).
volume	0.0 to 1.0	Normalized volume level for the recording stream.
max-mainloop-interval-usec	u64	The maximum interval between mainloop iterations in microseconds. This can be tweaked if the application is becoming too laggy (decreasing the value) or using too much CPU (increasing the value), but ideally there should be no need to tweak this. Defaults to 20000us (20ms).