1. About

butt (broadcast using this tool) is an easy to use, multi OS streaming tool.
It supports ShoutCast and IceCast and runs on Linux, MacOS and Windows.
The main purpose of butt is to stream live audio data from your computers Mic or Line input
to an Shoutcast or Icecast server. Recording is also possible.
It is NOT intended to be a server by itself or automatically broadcast audio files.

2. Install


Mount the butt-<version>.dmg by double clicking and
drop the butt file on the Applications folder.


Just run the butt-<version>-setup.exe and follow the installer pages.
The default installation path might be unusual, but this way it is possible to install
butt without administration rights.

Linux/MinGW (Windows):

Note: If you want to only install the butt-client, skip directly to the butt-client section below.
First of all the following libraries have to be installed on your system
fltk-1.3, portaudio19, libmp3lame, libvorbis, libogg, libflac,
libopus, libsamplerate, libfdk-aac,
libdbus-1, 'libcurl, libssl'
They are quite common and should be included in every popular linux distribution.

On Ubuntu you can install them with
sudo apt-get install libfltk1.3-dev portaudio19-dev libopus-dev libmp3lame-dev libvorbis-dev libogg-dev libflac-dev libfdk-aac-dev libdbus-1-dev libsamplerate0-dev libssl-dev libcurl4-openssl-dev

On openSUSE you can install them with
sudo zypper in fltk-devel portaudio-devel libmp3lame-devel libvorbis-devel libogg-devel flac-devel libfdk-aac-devel libopus-devel libopenssl-devel libopus-devel libsamplerate-devel dbus-1-devel curl-devel

On Distributions which don’t have libfdk-aac like debian you can compile without aac support with:
./configure --disable-aac

For compiling on Windows I recommend the msys2 x64 (www.msys2.org) environment.
They have all the needed packages in their pacman repository. Additionally you need to install the libwinpthread-git package.
Make sure that you select the x64 version of each package.

After installing the above libraries you can install butt from source as usual:

  • tar -xzf butt-<version>.tar.gz

  • cd butt-<version>

  • autoreconf -i (only on Windows/MSYS2)

  • ./configure

  • make

  • sudo make install

In case the included configure script or the make process fails on your system, try to create a new configure script by invoking: autoreconf -i and start with ./configure again.

3. butt-client

butt-client is a minimal binary which can be used to send commands to a running butt instance.
There are two ways to build butt-client:
1. Configure the build by adding --with-client to the configure command.
2. Configure it by adding --without-butt.
The first option builds both butt and butt-client and it requires all system dependencies.
The second option builds butt-client only and it requires none of the system dependencies.
This is the recommended option if you only need butt-client, especially if you are installing
it on a different machine. This is because the resulting binary is much smaller and it does
not link with any system dependencies, except the standard ones, which means that it is portable
as long as you copy it to another machine which shares the same operating system as the one you are building it on.

4. Quick start

When you start butt the first time, it will create a default configuration
file in in your home directory (~/.buttrc) on Linux and OS X or at
C:\Users\<username>\AppData\Roaming\buttrc on Windows.

In order to connect to a server, you need to add a new server in the config window.
Just open the settings window and click on [ADD].
Now fill in the input fields with the server credentials and click on the [ADD] at the lower right corner.
To connect to the server just press the play button in the main window and enjoy
your broadcast.

5. Install AAC libraries

  1. Download libfdk-aac-2.dll from here

  2. Go to the installation directory of butt by typing %LOCALAPPDATA%\butt into the file explorer

  3. Copy libfdk-aac-2.dll into the installation directory of butt

  4. Restart butt

  5. Enjoy AAC streaming

  1. Download and install butt_libfdkaac_macOS.pkg from here

  2. Restart butt

  3. Enjoy AAC streaming

Note: The installer will install libfdk-aac.2.dylib into /Library/Application Support/butt/


In case your Linux distribution ships butt without AAC support,
you need to install butt from source. Please refer to the Install section for more
information on that.

6. Configuration

The command line option -c <path_to_file> allows you to define a new standard configuration path.
This makes it possible to have multiple instances with different configurations
running. In case the file does not exists, butt will create a default file for you.
A tutorial on how to use the -c command line option to run multiple butt instances can be found here.

[Save]: Saves your current settings to the standard configuration
file or to the file that was passed to the -c option
[Export]: Saves your current settings to the given file
[Import]: Loads the selected file and applies the settings

If you use the -c command line option and import another configuration file
by using the import function, pressing [Save] will overwrite the file that was passed to the -c option.

In some cases the configuration file can become damaged and butt will not be able to start correctly. In that case you can hold down the shift key during butt startup to create a new configuration file.

7. Main Window

The dot matrix display shows you the current state of the butt software.
The states are: idle, streaming, recording.
When in streaming and/or recording state you can cycle through the information by clicking on the display.
You can choose between online duration, data sent, recording duration and data recorded

The [>] symbol shines yellow if butt is connected to a server.
The [O] symbol shines orange if the [start rec. when connected] checkbox is activated.
The [O] symbol shines red if butt is currently recording.

Additionally the play and record buttons change their color to yellow and red when butt is connected or recording.

Gain slider: The slider is only visible when to log window is visible as well.
With this slider you can attenuate and amplify the input signal between -24 dB and +24 dB, respectively.
Double clicking the slider resets the gain to 0 dB. Use this slider only to fine tune your input signal.
It does not change the operating systems input volume setting. Instead, the input signal is multiplied
by the given factor. Thus, adding too much gain will also add lots of noise.

VU meter: The vu meter shows the current streaming or recording volume in dBFS.

8. Audio Mixer

Click on [Mixer] to open the Audio Mixer. The mixer allows you to individually adjust the volume of your audio devices and have different volumes for streaming and recording. The Master Gain slider is coupled with the gain slider on the main window. The crossfader allows you to blend volumes between the primary and secondary audio device. Moving it from the center to one side lowers the volume of the other side.

9. Audio

The audio settings tab allows you to select your primary and secondary audio interface and the desired sample rate.
If you have a multi-channel audio device you may also select the desired input channels for the left and
right audio channel.

With the channel mode setting you tell butt if the audio stream shall be encoded to stereo or mono.
This brings us to 4 possible combinations.

Channel mode = Stereo and different channels are selected for Left and Right:

This is probably the most used combination.
Left and Right channels are encoded into a stereo stream.

Channel mode = Stereo and the same channel is selected for Left and Right:

The selected channel is used for Left and Right channel in a stereo stream.

Channel mode = Mono and different channels are selected for Left and Right:

Left and Right channels are averaged into a mono stream.

Channel mode = Mono and the same channel is selected for Left and Right:

The selected channel is used as mono channel in a mono stream.

The "Remember Device by" setting lets you choose if butt remembers the current device by its ID
or its name. As the ID may change when changing the number of connected audio devices on your computer
or when updating your operating system it is recommended to let butt remember the audio device by its name.

Clicking on [Update devices] will rescan the system for audio devices and update the Primary and Secondary
audio device list accordingly.

Within the Streaming and Recording section you can select invididual audio codecs and corresponding bitrate
for streaming and recording. Advanced users have the ability to change codec settings by clicking the gear symbol.

The Signal dection levels define at which level butt should treat the signal as present or absent.
These levels are used by the auto connect/disconnect or recording feature described below.

10. Streaming

To start streaming just click the play symbol.
butt will try to connect to the server until you press the stop button.
If the connection gets lost, butt will try to reconnect until the stop button is pressed

You can stream in 5 different audio codecs: mp3, aac+, ogg/vorbis, ogg/opus and ogg/FLAC.
In case opus is selected the sample rate is always resampled to 48 kHz.
Of course no resampling is needed if you select 48 kHz as sample rate.

Song name:

If you want to inform the listener about which song is currently playing you
can do that on the [Stream] tab.
You only need to type the song into the Song Name input field
and hit Enter or click [OK].

butt can also update the song automatically from a text file.
The first or the last line of the file must be the name of the song.
As soon as butt detects that the file has been changed, it updates the
name of the song on the server.

If you run butt on MacOS or Linux you can even transfer the current
song name from an audio player to butt.
Supported audio players:
Linux: Rhythmbox, Banshee, Clementine, Cantana, Spotify
MacOS: iTunes/Music, Vox, Spotify

As broadcasting with Icecast and Shoutcast is not realtime, the
listener receives the audio content with a few seconds delay.
This delay introduces an offset between the current song name and
the actual song that is playing. To prevent confusion on the listener
side you can add a delay to the automatic song update.

In case you want to add a prefix and/or a suffix to your song name
you can do that by entering the desired text into the corresponding
input field.

Stream infos:

In the [Main] settings window you can add stream infos.
This allows you to deliver more details about your stream.
For example the genre of your music, description of your station, web address etc.

Unfortunately, it is not possible to update stream infos during a broadcast.
You need to reconnect for updating the stream infos.

Automatic streaming:

If you activate the checkbox Start streaming after launch butt will
automatically connect to the server as soon as the application has been started.

butt can also connect and disconnect depending on the audio signal level:

To connect automatically if a signal is present for a certain amount of time
enter an integral number larger than 0 into the Start if signal is present for […​] seconds field.

To disconnect automatically if the signal is absent for a certain amount of time
enter an integral number larger than 0 into the Stop if signal is absent for […​] seconds field.

The default signal detection levels are set to -50.0 dB and can be independently changed
for the present and absent signal cases in the [Audio] tab.

11. Recording

butt is able to record and stream simultaneously in different bit rates.
For example you can stream with 96 kbit and record with 192 kbit.
Recording is possible in mp3, aac+, ogg/vorbis, ogg/opus, FLAC or wav.

To record your session you first need to select the destination folder and specify a file name
in the [Record] tab.
butt will replace specific date variables with the current time and date. For example rec_(%m_%d_%y).mp3 expands to rec_(03_28_2008).mp3.
Other possible time variables are %H (hours) %M (minutes) %S (seconds). Refer to the table below for more supported date variables.

With the %i variable you can add an index number to your file name.
This means with rec_%i.mp3 butt first tries to record to rec_0.mp3. In case that
file already exists, butt tries rec_1.mp3 …​

To manually start the recording simply press the record symbol.
To stop recording just click on the record symbol again.

Automatic recording:

If the start recording when connected checkbox is activated butt starts the
recording immediately after a connection with the server has been established.
Vice versa butt will stop the recording if the Stop recording when disconnected checkbox
is active.
Additionally you can tell butt to immediately start recording after the application has been
launched by checking the Start recording after launch box.

To start recording automatically if a signal is present for a certain amount of time
enter an integral number larger than 0 into the Start if signal is present for […​] seconds field.

To stop recording automatically if the signal is absent for a certain amount of time
enter an integral number larger than 0 into the Stop if signal is absent for […​] seconds field.

The default signal detection levels are set to -50.0 dB and can be independently changed
for the present and absent signal cases in the [Audio] tab.

You can also tell butt to split your recording into
separate files every n minutes. Just enter a number higher than 0
into the Split file every [..] minutes field.

Let’s assume your file name is rec_(%m_%d_%y)_%i.mp3 Then the first file is
expanded to rec\_(03_28_2008)_0-1.mp3, the second after n minutes to
rec_(03_28_2008)_0-2.mp3, the third to rec_(03_28_2008)_0-3.mp3, you got it.

If the sync to full hour checkbox is activated the automatic file splitting
is synchronized to the full hour. This means if the current time is 8:55 and file
splitting is set to 15 minutes, the second file starts at 9:00 and the third
at 9:15.
If you want to split the recording now, just click the [Split now] button.

Supported variables for file name expansion:

Variable Meaning


abbreviated weekday name (e.g. Fri)


full weekday name (e.g. Friday)


abbreviated month name (e.g. Oct)


full month name (e.g. October)


day of the month, as a number (1-31)


hour, 24 hour format (0-23)


hour, 12 hour format (1-12)


day of the year, as a number (1-366)


month as a number (1-12).


minute as a number (0-59)


AM or PM


second as a number (0-59)


week of the year, (0-53), where week 1 has the first Sunday


weekday as a decimal (0-6), where Sunday is 0


week of the year, (0-53), where week 1 has the first Monday


year in decimal, without the century (0-99)


year in decimal, with the century


time zone name

12. DSP

10-Band Equalizer:

The equalizer allows you to change the gain of certain frequency bands from -15 dB to 15 dB.
Note for professionals: The equalizer uses a Q of 2 on each frequency band.

Dynamic Range Compressor:

Dynamic range compression is used to reduce the difference between
loud and quiet parts of the signal, and thus provide a more consistent
experience for listeners. It is used by virtually all professional
radio stations.

The recommended procedure for configuring the compressor is as follows:

  1. Start playing the loudest audio source you intend to broadcast
    (typically music), and line it up with the master gain slider.

  2. Enable the compressor, and adjust the threshold and gain to suit.
    The attack and release times can generally be kept as they are, unless
    you have a particular reason to change them. You will notice that the
    overall signal level goes down, as it is being compressed.

  3. Adjust the makeup gain to bring the signal back to its original level.

  4. Now test with a quieter audio source (such as your voice), and see
    that the level of that is boosted in comparison. If the quieter source
    is still too quiet, reset the makeup gain to 0 and repeat from step 2
    onwards, until you have a satisfactory result.

This procedure can take some time to find the optimum settings, which
are determined by listening as much as by metering, but it generally
only needs to be done once - butt will save your settings, so once you
have values that work well for your content, you probably don’t need
to adjust them again.

As a rough guide, music should be compressed relatively subtly, with a
fairly high threshold and a ratio typically between 2 and 3. Pure
speech content can be compressed much more dramatically, with a low
threshold and a ratio of 5 or more; this will make the speech easier
for the listener to understand, and will also reduce the differences
between different speakers or by not keeping a very consistent
distance from the microphone.

For mixed speech and music broadcasting, it is recommended to set
butt’s compression as for music, and then have an additional
compressor (typically a hardware module) between the microphones and
the final mix.

To check if the signal power exceeds the threshold, the compressor usually
averages the signal power over time and compares it with the threshold.
This averaging process reduces the speed of the compressor. In case you need
a very fast responding compressor you can activate the Aggressive Mode option.
With this option enabled the compressor does not average the signal power
over time anymore.

13. Secure Connection over SSL/TLS (Icecast only)

To enable encryption for a certain server, you only have to activate the
Use SSL/TLS checkbox in the server settings. Please bear in mind that the
server must be configured with SSL/TLS support in order to make this working.
The connection will fail if you activate SSL/TLS for a server which does not
support encryption.
If the certficicate validation fails, butt will ask you if you want to trust
that certificate anyway. If you click on [TRUST] butt will establish the
connection and remembers the decision for that certificate and server.
By pressing the button [Revoke certificate trust] you can revoke that
If you want to specify your own file or folder with CA certificates,
you can enter the path to the file or folder in the [TLS] tab of the
settings window. Usually you should not need to enter any information there.

14. GUI settings

Within the [GUI] settings you can change certain settings to your personal


In case butt does not correctly detect your system language or you prefere a
different one you can select your preferred language here.
After changing the language a restart of butt is required.

Display Color:

Change the text and background color of the main display to your favorite color.

VU meter:

Select between gradient or solid colors for VU meter. For better visibility
the solid colors mode is recommended.
If the Always show tabs checkbox is unchecked the Streaming and Recording tabs
on the VU meter are only visible if you hover your mouse over the meter.

Attach settings window to main window:

If checked, the settings window will stick to the right side of the butt window.

Stay always on top:

If checked, butt will always be on top of other application windows.

Remember main window position:

If checked, butt will open on the previous position and screen.
In case the previous screen is not available butt will open on the default screen.
Additionally, this function also remembers the size of the log window.

Hide log window after start up:

If checked, butt will open with the log window hidden.

Change display mode every 5 seconds:

If checked, the display rotates automatically through the states
online duration, data sent, recording duration and data recorded.

Start minimized:

If checked, butt will start minimized to your Taskbar or Dock (macOS).

Disable gain control:

If checked, the gain control slider on the main window will be disabled.
This prevents users from accidentally changing the volume.

Show listeners:

If checked, butt retrieves the number of current listeners from
your server every 3 seconds.
If available the number of listeners are shown on the lower right corner at the display.

This feature only works with plain Icecast and Shoutcast servers.
It will probably not work if you use any streaming service provider.

15. The butt agent (Windows only)

Version 0.1.29 has introduced the little helper tool called butt agent.
The main purpose of the butt agent is to make it possible to minimize butt
into the windows system tray.
Minimizing to tray is not the only feature, though. You also have the
ability to let it display balloon notifications for connects/disconnects
and for song updates. If you want to start butt at windows start you can
also enable/disable this with the agent.
butt starts the agent automatically if the checkbox Minimize to tray
is enabled. If you want to use the balloon notifications you should activate
the Start agent at startup checkbox in the [Main] settings tab.
Once the agent has been started you will find it in the system tray.
From here you can manage the minimized butt instances and activate the
features mentioned above. A left click on the tray icon minimizes or raises
the last butt instance. A right click opens up a context menu with more
The butt agent closes itself if no more butt instance is running.

16. Command line control

butt can be controlled from command line.
If you want you can even control butt from a remote computer.
Please refer to the section below for more information on that.

17. Command line options

butt has several command line options which can be seperated into two modes.

Operating Mode:

These options change the behaviour of the instance you are about to start.

-c <path>:
This option allows you to select a different configuration path. It is useful if you
want to run several butt instances with different configurations. Just pass a different
configuration file with the -c option for every instance.

This option tells butt to accept control commands from your network or even the internet.

When using this option everyone in your network or even internet may
control your butt instance. Please use this option only if you have secured your network appropriately.

(uppercase U)
The command server will use UDP instead of TCP. If you pass the -U flag here you also need to pass it when sending control commands.

Use this option if you do not want to run a command server at all. This will also disable receiving commands from your local machine.

-p <port>:
With this option you can define the port of the command server. The default port is 1256. Use this option for example if you have several butt instances that you want to control from command line.

Control Mode:

With these options you can send control commands to a running butt instance.
Note that you can send these commands from either butt or butt-client binaries.

-s [name]:
(lowercase s)
This command tells butt to connect to the server name. If the name parameter is omitted, butt will connect to the currently selected server.

When receiving this command, butt will disconnect from the current server.

This command starts the recording engine.

Use this option to stop the recording.

In case a recording session is active this option splits the current file
like it would if you press the [Split now] button in the user interface.

Closes butt gracefully.

-u <song name>:
(lowercase u)
Sends a new song name to the server.

-M <threshold>:
Sends a new streaming signal threshold to update the server configuration.

-m <threshold>:
Sends a new streaming silence threshold to update the server configuration.

-O <threshold>:
Sends a new recording signal threshold to update the server configuration.

-o <threshold>:
Sends a new recording silence threshold to update the server configuration.

(uppercase S)
Requests a status information packet. The answer will be of the form:
connected: 1
connecting: 0
recording: 1
signal present: 1
signal absent: 0
stream seconds: 10
stream kBytes: 164
record seconds: 38
record kBytes: 3581
volume left: -6.2
volume right: -6.2
song: Stanley Clarke Trio - Under the Bridge
record path: /home/butt/recordings/recording_20220312.flac
listeners: 256

-a <address>:
Use this option to control a butt instance that is running on a remote computer.
In order to control a remote butt instance the butt instance must have been
started with the -A option. The parameter address can be either a IP address or a hostname.

-p <port>:
This should be set to the same port that has been given to the butt instance you want to control.
By default the command will be sent to port 1256.

(uppercase U)
Use this option to send commands via UDP instead of TCP.

18. Uninstall


Delete the butt.app from your Application folder and
remove the configuration file from /Users/<username>/.buttrc


Run the Uninstaller from the butt folder in your windows start menu.


Run sudo make uninstall from the source tree and
remove the configuration file from /home/<username>/.buttrc

19. Contact

butt at danielnoethen dot de

20. Donate

Paypal: paypal@danielnoethen.de
Patreon: Become a Patron
Apple Pay, Google Pay and more: Donorbox


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