Console-based Audio Visualizer for ALSA
thanks to anko for the gif, here is the recipe.
Demo video (old)
Table of Contents generated with DocToc
- C.A.V.A.
8/25/2015 - 0.3.4 - added setting of bar width, bar spacing and frequency bandwidth to config file.
8/9/2015 - 0.3.3 - autodetection of alsa loopback interface
7/16/2015 - 0.3.2 - added legacy ouput mode 'noncurses', for people experiencing issues with ncurses
7/15/2015 - 0.3.1 - added config file
7/12/2015 - 0.3.0 - Modular source code
5/23/2015 - 0.2.0 - Switched to ncurses
4/23/2015 - Fixed terminal window resizing, added smoothing
4/19/2015 - Added Monstercat style FFT easing (by CelestialWalrus).
9/22/2014 - Added support for mpd FIFO input.
C.A.V.A. is a bar spectrum analyzer for audio using ALSA for input. Its frequency range is limited to 50-10,000Hz. I know that the human ear can hear from 20 up to 20,000 Hz (and probably "sense" even higher frequencies), but the frequencies between 50-10,000Hz seem to me to be the most distinguishable. (I believe telephones used to be limited to as low as 8kHz.)
This program is not intended for scientific use.
This is my first published code. I am not a professional programmer so the source code is probably, by all conventions, a complete mess. Please excuse all the typos as I am both dyslexic and foreign.
Any tips or comments would be much appreciated.
- ALSA dev files
- FFTW
- ncursesw dev files (bundled in ncurses in arch)
This can be installed easily in all major distros:
Debian/Raspbian:
apt-get install libfftw3-dev libasound2-dev libncursesw5-dev
ArchLinux:
pacman -S base-devel fftw ncurses
openSUSE:
zypper install alsa-devel ncurses-devel fftw3-devel
make
You can use the following for compilation options, value in italic style is the default value:
Name | Value | Description |
---|---|---|
debug |
0 or 1 | Debugging message switch |
For example, turning on debugging messages:
make debug=1
Install cava
to default /usr/local
:
make install
Or you can change PREFIX
, for example:
make PREFIX=$HOME/.local install
make uninstall
Or:
make PREFIX=$HOME/.local uninstall
On openSUSE you need to add jubalh's home repository to install cava via zypper. For example for Tumbleweed do:
zypper ar -f http://download.opensuse.org/repositories/home:/jubalh/openSUSE_Tumbleweed/home:jubalh.repo
zypper in cava
If you use 13.2 or 13.1 just replace openSUSE_Tumbleweed with openSUSE_13.2, adjust it to your version.
If you want to capture audio straight fom the output (not just mic or line-in), you must create an ALSA loopback interface, then output the audio simultaneously to both the loopback and your normal interface.
To create a loopback interface simply run:
sudo modprobe snd_aloop
Hopefully your aplay -l
should now contain a loopback interface.
To make it presistent across boot add the line snd-aloop
to "/etc/modules". To keep it form beeing loaded as the first soundcard add the line options snd-aloop index=1
to "/etc/modprobe.d/alsa-base.conf", this will load it at '1' which is what cava uses as default. You can replace '1' with whatever makes most senes in your audio setup, but then cava must be specified to use that index. Simply pass the -d argument or alter the config file with the loopback interface index.
Playing the audio through your Loopback interface makes it possible for cava to to capture it, but there will be no sound in your speakers. :(
Not to worry! There are (at least) two ways of sending the audio output to the loopback and your actual audio interface at the same time:
First create the loopback device as explained in the section above.
To /etc/pulse/default.pa
, add the line load-module module-combine-sink
(in PulseAudio versions <1.0, the module was only called module-combine
). Then restart PulseAudio. For some reason, I had to turn off realtime scheduling for this to work on a Raspberry Pi (set realtime-scheduling = no
in /etc/pulse/daemon.conf
).
PulseAudio setup can also be done in paprefs (Debian: sudo apt-get install paprefs && paprefs
): In the far right tab check the box "Simultaneous Output".
An extra Output should appear in your sound options called "Simultaneous output to..." Note that when using this method if you turn down the volume on the Simultaneous output, this will effect the visualizer. To avoid this, select the actual output, turn down the volume, then select the Simultaneous output again.
First create the loopback device as explained in the section above.
Look at the inculded example file example_files/etc/asound.conf
. I was able to make this work on my laptop (an Asus UX31 running Elementary OS). I had no luck with the ALSA method on my Rasberry PI (Rasbian) with an USB DAC. The PulseAudio method however works perfectly on my PI.
Read more about the ALSA method here.
Add these lines in mpd:
audio_output {
type "fifo"
name "my_fifo"
path "/tmp/mpd.fifo"
format "44100:16:2"
}
Run cava with ./cava -i fifo
.
The path of the fifo can be specified with -p
.
I had some trouble with sync (the visualizer was ahead of the sound). Reducing the ALSA buffer in mpd fixed it:
audio_output {
type "alsa"
name "My ALSA"
buffer_time "50000" # (50ms); default is 500000 microseconds (0.5s)
}
To run via ssh to an external monitor, redirect output to /dev/console
:
~# ./cava [options] > /dev/console
exit with ctrl+z then run 'bg' to keep it running after you log out.
(You must be root to redirect to console. Simple sudo is not enough: Run sudo su
first.)
Since the graphics are simply based on characters, performance is dependent on the terminal font.
If you run this in a TTY the program will change the font to the included cava.psf
(actually a slightly modified "unifont").
In console fonts it seems that only 256 Unicode characters are supported, probably because they are bitmap fonts. I could not find a font with Unicode characters 2581-2587 (the 1/8 - 7/8 blocks used on the top of each bar to increase resolution).
So in cava.psf
, the characters 1-7 are actually replaced by Unicode characters 2581-2587. When cava exits, it changes the font back. If cava exits abnormally and you notice that 1-7 are replaced by partial blocks, just change the font with setfont
.
Actually, setfont
is supposed to return the default font, but this usually isn't set. I haven't found another way to get the current font. So cava sets the font to "Lat2-Fixed16" when interrupted. All major distros should have it. It will revert to your default font at reboot.
In terminal emulators like xterm
, the font settings is chosen in the software and cannot be changed by an application. So find your terminal settings and try out different fonts and settings. Also character spacing affects the look of the bar spectrum.
Cava also disables the terminal cursor, and turns it back on on exit, but in case it terminates unexpectedly, run setterm -cursor on
to get it back.e
Tip: Cava will look much nicer in small font sizes. Use a second terminal emulator for cava and set the font size to 1. Warning, can cause high CPU usage and latency if the terminal window is too large!
If you see latency issues (sound before image) in a terminal emulator, try increasing the font size. This will reduce the number of characters that have to be shown.
If your audio device has a huge buffer, you might experience that cava is actually faster then the audio you hear. This reduces the experience of the visualization. To fix this, you try decreasing the buffer settings in your audio playing software.
Usage : cava [options]
Visualize audio input in terminal.
Options:
-b 1..(console columns/2-1) or 200 number of bars in the spectrum (default 25 + fills up the console), program will automatically adjust if there are too many frequency bands)
-i 'input method' method used for listnening to audio, supports: 'alsa' and 'fifo'
-o 'output method' method used for outputting processed data, supports: 'ncurses', 'noncurses' and 'circle'
-d 'alsa device' name of alsa capture device (default 'hw:Loopback,1')
-p 'fifo path' path to fifo (default '/tmp/mpd.fifo')
-c foreground color suported colors: red, green, yellow, magenta, cyan, white, blue, black (default: cyan)
-C background color supported colors: same as above (default: no change)
-s sensitivity sensitivity percentage, 0% - no response, 50% - half, 100% - normal, etc...
-f framerate FPS limit, if you are experiencing high CPU usage, try redcing this (default: 60)
-m mode set mode (normal, scientific, waves)
-h print the usage
-v print version
Exit with ctrl+c.
If cava quits unexpectedly or is force killed, echo must be turned on manually with stty -echo
.
Key | Description |
---|---|
m | Swtich between smoothing modes |
up / down | increase/decrease sensitivity |
r | Reload configuration |
q or CTRL-C | Quit C.A.V.A. |
Configuration file is located in $XDG_CONFIG_HOME/cava/config
or $HOME/.config/cava/config
.
[general]
mode=normal
framerate=60
sensitivity=100
bars=0
bar_width = 3
bar_spacing = 1
lower_cutoff_freq = 300
higher_cutoff_freq = 15000
[input]
method=fifo
source=/tmp/mpd.fifo
[output]
method=ncurses
[color]
background=white
foreground=blue
[smoothing]
integral=0.7
monstercat=1
gravity=1
ignore=0
[eq]
; naming of keys doesn't matter
1=0.5
2=0.6
3=0.7
4=0.3
5=0.2
mode
defines smoothing mode, can benormal
,scientific
orwaves
. Default:normal
.framerate
is framerate (FPS). Default:60
. Accepts only non-negative values.sensitivity
is sensitivity %. Default:100
. Accepts only non-negative values.bars
defines the amount of bars.0
sets it to auto. Default:0
. Accepts only non-negative values.bar_width
width of bars in chrachters. Default3
.bar_spacing
space between bars in charachters. Default1
.lower_cutoff_freq
defines the lower cutof frequency for the far left bar. Default:50
.higher_cutoff_freq
defines the higher cutoff frequency for the far right bar. Default:10000
. Note: there is a minimum total bandwith of 43Mhz x number of bars. Cava will automaticly increase the higher cuttoff if a too low band is specified.
method
may bealsa
orfifo
.source
is the ALSA path or FIFO path.
method
may bencurses
,noncurses
orcircle
.
background
is the background color.foreground
is the foreground (bars) color.
integral
sets the multiplier for the integral smoothing calculations. Default:0.7
. Another example:0.5
. Accepts only non-negative values.monstercat
disables or enables the so-called "Monstercat smoothing". Default:1
. Accepts only0
or1
.gravity
sets the gravity multiplier. Default:1
. Accepts only non-negative values.ignore
zeroes bars with height lower than this setting's value. Default:0
. Accepts only non-negative values.
This one is tricky. You can have as much keys as you want. More keys = more precision.
How it works:
- Cava takes values from this section in the order of appearance (naming of the keys doesn't really matter) and puts them into an array.
- Visualization is divided into
x
sections (where x is the amount of values) and all bars in each of these sections are multiplied by the corresponding value from that array.
Examples:
[eq]
1=0
2=1
3=0
4=1
5=0
[eq]
1=2
2=2
3=1
4=1
5=0.5