dsp is an audio processing program with an interactive mode.
- GNU Make
- pkg-config
- fftw3: For
resample
,fir
,fir_p
, andhilbert
effects. - zita-convolver: For the
zita_convolver
effect. - libsndfile: For sndfile input/output support (recommended).
- ffmpeg (libavcodec, libavformat, and libavutil): For ffmpeg input support.
- alsa-lib: For alsa input/output support.
- libao: For ao output support.
- libmad: For mp3 input support.
- libpulse-simple: For PulseAudio input/ouput support.
- LADSPA: For the LADSPA frontend and the
ladspa_host
effect. - libltdl (libtool): For the
ladspa_host
effect.
$ make
Run ./configure [options]
manually if you want to build with non-default
options. Run ./configure --help
to see all available options.
# make install
dsp [options] path ... [!] [:channel_selector]
[@[~/]effects_file] [effect [args ...]] ...
Flag | Description |
---|---|
-h |
Show help text. |
-b frames |
Set buffer size (must be given before the first input). |
-R ratio |
Set codec maximum buffer ratio (must be given before the first input). |
-i |
Force interactive mode. |
-I |
Disable interactive mode. |
-q |
Disable progress display. |
-s |
Silent mode. |
-v |
Verbose mode. |
-d |
Force dithering. |
-D |
Disable dithering. |
-E |
Don't drain effects chain before rebuilding. |
-p |
Plot effects chain instead of processing audio. |
-V |
Enable verbose progress display. |
-S |
Use "sequence" input combining mode. |
Flag | Description |
---|---|
-o |
Output. |
-t type |
Type. |
-e encoding |
Encoding. |
-B/L/N |
Big/little/native endian. |
-r frequency[k] |
Sample rate. |
-c channels |
Number of channels. |
-n |
Equivalent to -t null null . |
Type | Modes | Encodings |
---|---|---|
null | rw | sample_t |
sgen | r | sample_t |
sndfile | r | autodetected |
wav | rw | s16 u8 s24 s32 float double mu-law a-law ima_adpcm ms_adpcm gsm6.10 g721_32 |
aiff | rw | s16 s8 u8 s24 s32 float double mu-law a-law ima_adpcm gsm6.10 dwvw_12 dwvw_16 dwvw_24 |
au | rw | s16 s8 s24 s32 float double mu-law a-law g721_32 g723_24 g723_40 |
raw | rw | s16 s8 u8 s24 s32 float double mu-law a-law gsm6.10 vox_adpcm dwvw_12 dwvw_16 dwvw_24 |
paf | rw | s16 s8 s24 |
svx | rw | s16 s8 |
nist | rw | s16 s8 s24 s32 mu-law a-law |
voc | rw | s16 u8 mu-law a-law |
ircam | rw | s16 s32 float mu-law a-law |
w64 | rw | s16 u8 s24 s32 float double mu-law a-law ima_adpcm ms_adpcm gsm6.10 |
mat4 | rw | s16 s32 float double |
mat5 | rw | s16 u8 s32 float double |
pvf | rw | s16 s8 s32 |
xi | rw | dpcm_8 dpcm_16 |
htk | rw | s16 |
sds | rw | s16 s8 s24 |
avr | rw | s16 s8 u8 |
wavex | rw | s16 u8 s24 s32 float double mu-law a-law |
sd2 | rw | s16 s8 s24 |
flac | rw | s16 s8 s24 |
caf | rw | s16 s8 s24 s32 float double mu-law a-law |
wve | rw | a-law |
ogg | rw | vorbis |
mpc2k | rw | s16 |
rf64 | rw | s16 u8 s24 s32 float double mu-law a-law |
ffmpeg | r | autodetected |
alsa | rw | s16 u8 s8 s24 s24_3 s32 float double |
ao | w | s16 u8 s32 |
mp3 | r | mad_f |
pcm | rw | s16 u8 s8 s24 s32 float double |
pulse | rw | s16 u8 s24 s24_3 s32 float |
In concatenate mode (the default), the inputs are concatenated in the order given and sent to the output. All inputs must have the same sample rate and number of channels.
In sequence mode, the inputs are sent serially to the output like concatenate
mode, but the inputs do not need to have the same sample rate or number of
channels. The effects chain and/or output will be rebuilt/reopened when
required. Note that if the output is a file, the file will be truncated if it
is reopened. This mode is most useful when the output is an audio device, but
can also be used to concatenate inputs with different sample rates and/or
numbers of channels into a single output file when used with the resample
and/or remix
effects.
The sgen
input type is a basic (for now, at least) signal generator that can
generate impulses and exponential sine sweeps. The syntax for the path
argument is as follows:
[type[@channel_selector][:arg[=value]...]][/type...][+len[s|m|S]]
type
may be sine
for sine sweeps or tones, or delta
for a delta function
(impulse). sine
accepts the following arguments:
freq=f0[k][-f1[k]]
Frequency. Iflen
is set andf1
is given, an exponential sine sweep is generated.
The arguments for delta
are:
offset=time[s|m|S]
Offset in seconds, miliseconds or samples.
Example:
$ dsp -t sgen -c 2 sine@0:freq=500-1k/sine@1:freq=300-800+2 gain -10
-
lowpass_1 f0[k]
First-order lowpass filter. -
highpass_1 f0[k]
First-order highpass filter. -
allpass_1 f0[k]
First-order allpass filter. -
lowshelf_1 f0[k] gain
First-order lowshelf filter. -
highshelf_1 f0[k] gain
First-order highshelf filter. -
lowpass_1p f0[k]
Single pole lowpass (EWMA) filter. -
lowpass f0[k] width[q|o|h|k]
Second-order lowpass filter. -
highpass f0[k] width[q|o|h|k]
Second-order highpass filter. -
bandpass_skirt f0[k] width[q|o|h|k]
Second-order bandpass filter with constant skirt gain. -
bandpass_peak f0[k] width[q|o|h|k]
Second-order bandpass filter with constant peak gain. -
notch f0[k] width[q|o|h|k]
Second-order notch filter. -
allpass f0[k] width[q|o|h|k]
Second-order allpass filter. -
eq f0[k] width[q|o|h|k] gain
Second-order peaking filter. -
lowshelf f0[k] width[q|s|d|o|h|k] gain
Second-order lowshelf filter. -
highshelf f0[k] width[q|s|d|o|h|k] gain
Second-order highshelf filter. -
linkwitz_transform fz[k] qz fp[k] qp
Linkwitz transform (see http://www.linkwitzlab.com/filters.htm#9). -
deemph
Compact Disc de-emphasis filter. -
biquad b0 b1 b2 a0 a1 a2
Biquad filter. -
gain [channel] gain
Gain adjustment. Ignores the channel selector when thechannel
argument is given. -
mult [channel] multiplier
Multiplies each sample bymultiplier
. Ignores the channel selector when thechannel
argument is given. -
add [channel] value
Applies a DC shift. Ignores the channel selector when thechannel
argument is given. -
crossfeed f0[k] separation
Simple crossfeed for headphones. Very similar to Linkwitz/Meier/CMoy/bs2b crossfeed. -
matrix4 [[options] surround_level]
2-to-4 channel (2 front and 2 surround) active matrix upmixer designed for plain (i.e. unencoded) stereo material. The matrix coefficients and the main ideas behind the steering behavior come from David Griesinger's published works on matrix surround.The intended speaker configuration is fronts at ±30° and surrounds between ±60° and ±120°. The surround speakers must be calibrated correctly in level and frequency response for best results. No frequency contouring or delay is done internally, so it is highly recommended to apply
delay
andlowpass_1
effects to the surround outputs:matrix4 -6 :2,3 delay 15m lowpass_1 6k :
The settings shown above (-6dB surround level, 15ms delay, and 6kHz rolloff) are a good starting point, but may be adjusted to taste. The default
surround_level
is -6dB.The front outputs replace the original input channels and the surround outputs are appended to the end of the channel list.
Options are given as a comma-separated list. Recognized options are:
no_dir_boost
Disable directional boost of front channels.show_status
Show a status line (slightly broken currently, but still useful for debugging).signal
Toggle the effect wheneffect.signal()
is called.
-
remix channel_selector|. ...
Select and mix input channels into output channels. Each channel selector specifies the input channels to be mixed to produce each output channel..
selects no input channels. For example,remix 0,1 2,3
mixes input channels 0 and 1 into output channel 0, and input channels 2 and 3 into output channel 1.remix -
mixes all input channels into a single output channel. -
st2ms
Convert stereo to mid/side. -
ms2st
Convert mid/side to stereo. -
delay delay[s|m|S]
Delay line. The unit for the delay argument depends on the suffix used:s
is seconds (the default),m
is milliseconds, andS
is samples. -
resample [bandwidth] fs[k]
Sinc resampler. Ignores the channel selector. -
fir [file:][~/]filter_path|coefs:list[/list...]
Non-partitioned 64-bit direct/FFT convolution. Latency is zero for filters up to 16 samples. For longer filters, the latency is equal to thefft_len
reported in verbose mode. Eachlist
is a comma-separated list of coefficients for one filter channel. Missing values are filled with zeros. -
fir_p [max_part_len] [file:][~/]filter_path|coefs:list[/list...]
Zero-latency non-uniform partitioned 64-bit direct/FFT convolution. Runs slower than thezita_convolver
effect, but useful if you need higher precision and/or zero latency.max_part_len
must be a power of 2. Eachlist
is a comma-separated list of coefficients for one filter channel. Missing values are filled with zeros. -
zita_convolver [min_part_len [max_part_len]] [~/]filter_path
Partitioned 32-bit FFT convolution using the zita-convolver library. Latency is equal tomin_part_len
(64 samples by default).{min,max}_part_len
must be powers of 2 between 64 and 8192. -
hilbert [-p] taps
Simple FIR approximation of a Hilbert transform. The number of taps must be odd. Bandwidth is controlled by the number of taps. If-p
is given, thefir_p
convolution engine is used instead of the defaultfir
engine. -
decorrelate [-m] [stages]
Allpass decorrelator as described in "Frequency-Dependent Schroeder Allpass Filters" by Sebastian J. Schlecht (doi:10.3390/app10010187). If-m
is given, the same filter parameters are used for all input channels. The default number of stages is 5, which results in an average group delay of about 8.5ms at high frequencies. -
noise level
Add TPDF noise. Thelevel
argument specifies the peak level of the noise (dBFS). -
ladspa_host module_path plugin_label [control ...]
Apply a LADSPA plugin. Supports any number of input/output ports (with the exception of zero output ports). Plugins with zero input ports will replace selected input channels with their output(s). If a plugin has one or zero input ports, it will be instantiated multiple times to handle multi-channel input.Controls which are not explicitly set or are set to
-
will use default values (if available).The
LADSPA_PATH
environment variable can be used to set the search path for plugins. -
stats [ref_level]
Display the DC offset, minimum, maximum, peak level (dBFS), RMS level (dBFS), crest factor (dB), peak count, peak sample, number of samples, and length (s) for each channel. Ifref_level
is given, peak and RMS levels relative toref_level
will be shown as well (dBr).
A !
marks the effect that follows as "non-essential". If an effect is marked
non-essential and it fails to initialize, it will be skipped.
[[start][-[end]][,...]]
Example | Description |
---|---|
<empty> |
all |
- |
all |
2- |
2 to n |
-4 |
0 through 4 |
1,3 |
1 and 3 |
1-4,7,9- |
1 through 4, 7, and 9 to n |
Suffix | Description |
---|---|
q |
Q-factor (default). |
s |
Slope (shelving filters only). |
d |
Slope in dB/octave (shelving filters only). Also changes the definition of f0 from center frequency to corner frequency (like Room EQ Wizard and the Behringer DCX2496). |
o |
Bandwidth in octaves. |
h |
Bandwidth in Hz. |
k |
Bandwidth in kHz. |
- On the command line, relative paths are relative to
$PWD
. - Within an effects file, relative paths are relative to the directory containing said effects file.
- The
~/
prefix will be expanded to the contents of$HOME
.
- Arguments are delimited by whitespace.
- If the first non-whitespace character in a line is
#
, the line is ignored. - The
\
character removes any special meaning of the next character.
Example:
gain -10
# This is a comment
eq 1k 1.0 +10.0 eq 3k 3.0 -4.0
lowshelf 90 0.7 +4.0
Effects files inherit a copy of the current channel selector. In other words, if an effects chain is this:
:2,4 @eq_file.txt eq 2k 1.0 -2.0
eq_file.txt
will inherit the 2,4
selector, but any selector specified
within eq_file.txt
will not affect the eq 2k 1.0 -2.0
effect that comes
after it.
Read file.flac
, apply a bass boost, and write to alsa device hw:2
:
dsp file.flac -ot alsa -e s24_3 hw:2 lowshelf 60 0.5 +4.0
Plot amplitude vs frequency for a complex effects chain:
dsp -pn gain -1.5 lowshelf 60 0.7 +7.8 eq 50 2.0 -2.7 eq 100 2.0 -3.9
eq 242 1.0 -3.8 eq 628 2.0 +2.1 eq 700 1.5 -1.0
lowshelf 1420 0.68 -12.5 eq 2500 1.3 +3.0 eq 3000 8.0 -1.8
eq 3500 2.5 +1.4 eq 6000 1.1 -3.4 eq 9000 1.8 -5.6
highshelf 10000 0.7 -0.5 | gnuplot
Implement an LR4 crossover at 2.2KHz, where output channels 0 and 2 are the left and right woofers, and channels 1 and 3 are the left and right tweeters, respectively:
dsp stereo_file.flac -ot alsa -e s32 hw:3 remix 0 0 1 1 :0,2
lowpass 2.2k 0.707 lowpass 2.2k 0.707 :1,3 highpass 2.2k 0.707
highpass 2.2k 0.707 :
Apply effects from a file:
dsp file.flac @eq.txt
ladspa_dsp
looks for configuration files in the following directories:
$XDG_CONFIG_HOME/ladspa_dsp
$HOME/.config/ladspa_dsp
(if$XDG_CONFIG_HOME
is not set)/etc/ladspa_dsp
To override the default directories, set the LADSPA_DSP_CONFIG_PATH
environment variable to the desired path(s) (colon-separated).
Each file that is named either config
or config_<name>
(where <name>
is
any string) is loaded as a separate plugin. The plugin label is either
ladspa_dsp
(for config
) or ladspa_dsp:<name>
(for config_<name>
).
Configuration files are a simple key-value format. Leading whitespace is ignored. The valid keys are:
input_channels
Number of input channels. Default value is1
. May be left unset unless you want individual control over each channel.output_channels
Number of output channels. Default value is1
. Initialization will fail if this value is set incorrectly.LC_NUMERIC
SetLC_NUMERIC
to the given value while building the effects chain. If the decimal separator defined by your system locale is something other than.
, you should set this toC
(to use.
as the decimal separator) or an empty value (to use the decimal separator defined by your locale).effects_chain
String to build the effects chain. The format is the same as an effects file, but only a single line is interpreted.
Example configuration:
# This is a comment
input_channels=1
output_channels=1
LC_NUMERIC=C
effects_chain=gain -3.0 lowshelf 100 1.0s +3.0 @/path/to/eq_file
Relative file paths in the effects_chain
line are relative to the
directory in which the configuration file resides.
The loglevel can be set to VERBOSE
, NORMAL
, or SILENT
through the
LADSPA_DSP_LOGLEVEL
environment variable.
Put this in ~/.asoundrc
:
pcm.dsp {
type plug
slave {
format FLOAT
rate unchanged
channels unchanged
pcm {
type ladspa
path "/usr/lib/ladspa"
playback_plugins [{
label "ladspa_dsp"
}]
slave.pcm {
type plug
slave {
pcm "<hw_device>"
rate unchanged
channels unchanged
}
}
}
}
}
Replace <hw_device>
with the preferred output device (hw:0
, for example).
If you need individual control over each channel, you need to set the number of (output) channels:
pcm.dsp {
type plug
slave {
format FLOAT
rate unchanged
pcm {
type ladspa
channels <channels>
path "/usr/lib/ladspa"
playback_plugins [{
label "ladspa_dsp"
}]
slave.pcm {
type plug
slave {
pcm "<hw_device>"
rate unchanged
channels unchanged
}
}
}
}
}
To make dsp
the default device, append this to ~/.asoundrc
:
pcm.!default {
type copy
slave.pcm "dsp"
}
Usage example: Route pulseaudio audio through ladspa_dsp (tested with Ubuntu 18.04; contributed by shaffenmeister)
- Prepare .asoundrc as stated above.
- Determine pulseaudio master sink using
pacmd list sinks
. Use attributename
of the pulseaudio sink you plan to use (e.g.alsa_output.pci-0000_00_14.2.analog-stereo
). - Execute
analyseplugin <path to LADSPA plugin>/ladspa_dsp.so
to determine plugin name and label. - Run
pacmd load-module module-ladspa-sink sink_name=ladspa_out sink_master=<master_sink> plugin=<plugin name> label=<plugin label>
. - Select new LADSPA sink as system sink (Ubuntu 18.04 Desktop:
Settings > Sound > Output > LADSPA_Plugin
<plugin label>
on<master sink>
).
Example:
pacmd list sinks
analyseplugin /usr/local/lib/ladspa/ladspa_dsp.so
pacmd load-module module-ladspa-sink sink_name=ladspa_out sink_master=alsa_output.pci-0000_00_14.2.analog-stereo plugin=ladspa_dsp label=ladspa_dsp
To load the LADSPA module at system startup for all users include settings in /etc/pulse/default.pa
:
.ifexists module-ladspa-sink.so
.nofail
load-module module-ladspa-sink sink_name=ladspa_out sink_master=<master_sink> plugin=<plugin name> label=<plugin label>
.fail
.endif
To load the LADSPA module at user login include settings in
~/.config/pulse/default.pa
:
#!/usr/bin/pulseaudio -nF
.include /etc/pulse/default.pa
.ifexists module-ladspa-sink.so
.nofail
load-module module-ladspa-sink sink_name=ladspa_out sink_master=<master_sink> plugin=<plugin name> label=<plugin label>
.fail
.endif
Note: The resample effect cannot be used with the LADSPA frontend.
- No support for metadata.
- Some effects do not support plotting.
This software is released under the ISC license.