1DSP(1) General Commands Manual DSP(1)
2
6 dsp - an audio processing program with an interactive mode
7
9 dsp [options] path ... [!] [:channel_selector] [@[~/]effects_file]
10 [effect [args ...]] ...
11
13 dsp is an audio processing program with an interactive mode.
14
16 Global options
17 -h Show help text.
18 -b frames
20 Set buffer size (must be given before the first input).
21 -R ratio
23 Set codec maximum buffer ratio (must be given before the first
24 input).
25 -i Force interactive mode.
27 -I Disable interactive mode.
29 -q Disable progress display.
31 -s Silent mode.
33 -v Verbose mode.
35 -d Force dithering.
37 -D Disable dithering.
39 -E Don't drain effects chain before rebuilding.
41 -p Plot effects chain instead of processing audio.
43 -V Enable verbose progress display.
45 -S Use `sequence' input combining mode.
47 Input/output options
49 -o Output.
50 -t type
52 Type.
53 -e encoding
55 Encoding.
56 -B/L/N Big/little/native endian.
58 -r frequency[k]
60 Sample rate.
61 -c channels
63 Number of channels.
64 -n Equivalent to
66 -t null null.
67
69 For a complete list of supported input/output types, run
70 $ dsp -h
71 Input combining modes
73 In concatenate mode (the default), the inputs are concatenated in the
74 order given and sent to the output. All inputs must have the same sam‐
75 ple rate and number of channels.
76 In sequence mode, the inputs are sent serially to the output like con‐
78 catenate mode, but the inputs do not need to have the same sample rate
79 or number of channels. The effects chain and/or output will be
80 rebuilt/reopened when required. Note that if the output is a file, the
81 file will be truncated if it is reopened. This mode is most useful when
82 the output is an audio device, but can also be used to concatenate
83 inputs with different sample rates and/or numbers of channels into a
84 single output file when used with the resample and/or remix effects.
85
87 Full effects list
88 lowpass_1 f0[k]
89 Single-pole lowpass filter.
90 highpass_1 f0[k]
92 Single-pole highpass filter.
93 lowpass f0[k] width[q|o|h|k]
95 Double-pole lowpass filter.
96 highpass f0[k] width[q|o|h|k]
98 Double-pole highpass filter.
99 bandpass_skirt f0[k] width[q|o|h|k]
101 Double-pole bandpass filter with constant skirt gain.
102 bandpass_peak f0[k] width[q|o|h|k]
104 Double-pole bandpass filter with constant peak gain.
105 notch f0[k] width[q|o|h|k]
107 Double-pole notch filter.
108 allpass f0[k] width[q|o|h|k]
110 Double-pole allpass filter.
111 eq f0[k] width[q|o|h|k] gain
113 Double-pole peaking filter.
114 lowshelf f0[k] width[q|s|d|o|h|k] gain
116 Double-pole lowshelf filter.
117 highshelf f0[k] width[q|s|d|o|h|k] gain
119 Double-pole highshelf filter.
120 linkwitz_transform fz[k] qz fp[k] qp
122 Linkwitz transform (see http://www.linkwitzlab.com/fil‐
123 ters.htm#9).
124 deemph Compact Disc de-emphasis filter.
126 biquad b0 b1 b2 a0 a1 a2
128 Biquad filter.
129 gain [channel] gain
131 Gain adjustment. Ignores the channel selector when the channel
132 argument is given.
133 mult [channel] multiplier
135 Multiplies each sample by multiplier. Ignores the channel selec‐
136 tor when the channel argument is given.
137 crossfeed f0[k] separation
139 Simple crossfeed for headphones. Very similar to
140 Linkwitz/Meier/CMoy/bs2b crossfeed.
141 remix channel_selector|. ...
143 Select and mix input channels into output channels. Each channel
144 selector specifies the input channels to be mixed to produce
145 each output channel. `.' selects no input channels. For exam‐
146 ple,
147 remix 0,1 2,3
148 mixes input channels 0 and 1 into output channel 0, and input
149 channels 2 and 3 into output channel 1.
150 remix -
151 mixes all input channels into a single output channel.
152 delay delay[s|m|S]
154 Delay line. The unit for the delay argument depends on the suf‐
155 fix used: `s' is seconds (the default), `m' is milliseconds, and
156 `S' is samples.
157 resample [bandwidth] fs[k]
159 Sinc resampler. Ignores the channel selector.
160 fir [~/]impulse_path
162 Non-partitioned 64-bit FFT convolution. Latency is equal to the
163 length of the impulse.
164 zita_convolver [min_part_len [max_part_len]] [~/]impulse_path
166 Partitioned 32-bit FFT convolution using the zita-convolver
167 library. Latency is equal to min_part_len (64 samples by
168 default). {min,max}_part_len must be powers of 2 between 64 and
169 8192.
170 noise level
172 Add TPDF noise. The level argument specifies the peak level of
173 the noise (dBFS).
174 compress thresh ratio attack release
176 Compress or expand the dynamic range. This effect peak-sensing
177 and input channels are linked. If the ratio is in (1,inf), the
178 dynamic range will be compressed. If the ratio is in (0,1), the
179 dynamic range will be expanded. Attack refers to decreases in
180 gain and release refers to increases in gain.
181 reverb [-w] [reverberance [hf_damping [room_scale [stereo_depth
183 [pre_delay [wet_gain]]]]]]
184 Add reverberation using the freeverb algorithm. Effect ported
185 from libSoX. reverberance, hf_damping, room_scale, and
186 stereo_depth are in percent. pre_delay is in seconds.
187 g2reverb [-w] [room_size [reverb_time [input_bandwidth [damping
189 [dry_level [reflection_level [tail_level]]]]]]]
190 Add reverberation using Fons Adriaensen's g2reverb algorithm.
191 ladspa_host module_path plugin_label [control ...]
193 Apply a LADSPA plugin. Supports any number of input/output ports
194 (with the exception of zero output ports). Plugins with zero
195 input ports will replace selected input channels with their out‐
196 put(s). If a plugin has one or zero input ports, it will be
197 instantiated multiple times to handle multi-channel input.
198 Controls which are not explicitly set or are set to `-' will use
200 default values (if available).
201 The `LADSPA_PATH' environment variable can be used to set the
203 search path for plugins.
204 stats [ref_level]
206 Display the DC offset, minimum, maximum, peak level (dBFS), RMS
207 level (dBFS), crest factor (dB), peak count, peak sample, number
208 of samples, and length (s) for each channel. If ref_level is
209 given, peak and RMS levels relative to ref_level will be shown
210 as well (dBr).
211 Exclamation mark
213 A `!' marks the effect that follows as `non-essential'. If an effect is
214 marked non-essential and it fails to initialize, it will be skipped.
215 Selector syntax
217 [[start][-[end]][,...]]
218 Example Description
220 ──────────────────────────────────────
221 <empty> all
222 - all
223 2- 2 to n
224 -4 0 through 4
225 1,3 1 and 3
226 1-4,7,9- 1 through 4, 7, and 9 to n
227 Width suffixes
229 Suffix Description
230 ─────────────────────────────────────────────────────
231 q Q-factor (default).
232 s Slope (shelving filters only).
233 d Slope in dB/octave (shelving filters only).
234 o Bandwidth in octaves.
235 h Bandwidth in Hz.
236 k Bandwidth in kHz.
237 Note: The `d' width suffix also changes the definition of f0 from cen‐
239 ter frequency to corner frequency (like Room EQ Wizard and the
240 Behringer DCX2496).
241 File paths
243 * On the command line, relative paths are relative to `$PWD'.
244 * Within an effects file, relative paths are relative to the
246 directory containing said effects file.
247 * The `~/' prefix will be expanded to the contents of `$HOME'.
249 Effects file syntax
251 * Arguments are delimited by whitespace.
252 * If the first non-whitespace character in a line is `#', the line
254 is ignored.
255 * The `\' character removes any special meaning of the next char‐
257 acter.
258 Example:
260 gain -10
261 # This is a comment
262 eq 1k 1.0 +10.0 eq 3k 3.0 -4.0
263 lowshelf 90 0.7 +4.0
264 Effects files inherit a copy of the current channel selector. In other
266 words, if an effects chain is this:
267 :2,4 @eq_file.txt eq 2k 1.0 -2.0
268 eq_file.txt will inherit the `2,4' selector, but any selector specified
269 within eq_file.txt will not affect the `eq 2k 1.0 -2.0' effect that
270 comes after it.
271
273 Read file.flac, apply a bass boost, and write to alsa device hw:2:
274 dsp file.flac -ot alsa -e s24_3 hw:2 lowshelf 60 0.5 +4.0
275 Plot amplitude vs frequency for a complex effects chain:
277 dsp -pn gain -1.5 lowshelf 60 0.7 +7.8 eq 50 2.0 -2.7 eq 100 2.0 -3.9
278 eq 242 1.0 -3.8 eq 628 2.0 +2.1 eq 700 1.5 -1.0
279 lowshelf 1420 0.68 -12.5 eq 2500 1.3 +3.0 eq 3000 8.0 -1.8
280 eq 3500 2.5 +1.4 eq 6000 1.1 -3.4 eq 9000 1.8 -5.6
281 highshelf 10000 0.7 -0.5 | gnuplot
282 Implement an LR4 crossover at 2.2KHz, where output channels 0 and 2 are
284 the left and right woofers, and channels 1 and 3 are the left and right
285 tweeters, respectively:
286 dsp stereo_file.flac -ot alsa -e s32 hw:3 remix 0 0 1 1 :0,2
287 lowpass 2.2k 0.707 lowpass 2.2k 0.707 :1,3 highpass 2.2k 0.707
288 highpass 2.2k 0.707 :
289 Apply effects from a file:
291 dsp file.flac @eq.txt
292
294 Configuration
295 ladspa_dsp looks for configuration files in the following directories:
296 * $XDG_CONFIG_HOME/ladspa_dsp
299 * $HOME/.config/ladspa_dsp (if $XDG_CONFIG_HOME is not set)
301 * /etc/ladspa_dsp
303 To override the default directories, set the `LADSPA_DSP_CONFIG_PATH'
305 environment variable to the desired path(s) (colon-separated).
306 Each file that is named either config or config_<name> (where <name> is
308 any string) is loaded as a separate plugin. The plugin label is either
309 ladspa_dsp (for config) or ladspa_dsp:<name> (for config_<name>).
310 Configuration files are a simple key-value format. Leading whitespace
312 is ignored. The valid keys are:
313 input_channels
315 Number of input channels. Default value is 1. May be left unset
316 unless you want individual control over each channel.
317 output_channels
319 Number of output channels. Default value is 1. Initialization
320 will fail if this value is set incorrectly.
321 LC_NUMERIC
323 Set `LC_NUMERIC' to the given value while building the effects
324 chain. If the decimal separator defined by your system locale is
325 something other than `.', you should set this to `C' (to use `.'
326 as the decimal separator) or an empty value (to use the decimal
327 separator defined by your locale).
328 effects_chain
330 String to build the effects chain. The format is the same as an
331 effects file, but only a single line is interpreted.
332 Example configuration:
334 # This is a comment
335 input_channels=1
336 output_channels=1
337 LC_NUMERIC=C
338 effects_chain=gain -3.0 lowshelf 100 1.0s +3.0 @/path/to/eq_file
339 Relative file paths in the effects_chain line are relative to the
341 directory in which the configuration file resides.
342 The loglevel can be set to `VERBOSE', `NORMAL', or `SILENT' through the
344 `LADSPA_DSP_LOGLEVEL' environment variable.
345 Note: The resample effect cannot be used with the LADSPA frontend.
347 Examples
349 See https://github.com/bmc0/dsp/blob/master/README.md for usage exam‐
350 ples.
351
353 No support for metadata.
354 Some effects do not support plotting.
356
358 This software is released under the ISC license, except for the reverb
359 effect, which is under the LGPLv2.1 license (copyright
360 robs@users.sourceforge.net), and the g2reverb effect, which is under
361 the GPLv2 license (copyright Fons Adriaensen <fons@linuxaudio.org>).
362 See the LICENSE files for more details.
363 dsp-1.6 DSP(1)