ecasound

SIGNAL ANALYSIS

-ev

Analyze sample data to find out how much the signal can be amplified without clipping. The resulting percent value can be used as a parameter to -ea and -eas effects. Also prints a statistics table containing info about stereo-image and how different sample values are used.

-ezf

Find the optimal value for DC-adjusting. You can use the result as a parameter to -ezx effect.

GENERAL SIGNAL PROCESSING ALGORITHMS

-ea:amplify-%,max-clipped-samples

Amplifies signal by amplify-% percent. If number of consecutive clipped samples (resulting sample has the largest amplitude possible) reaches 'max-clipped-samples', a warning will be issued.

-eas:amplify-%

Otherwise like -ea, but doesn't warn about clipped samples.

-ec:rate,threshold

Compressor (a simple one). 'rate' is the compression rate in decibels ('rate'dB change in input signal causes 1dB change in output). 'threshold' varies between 0.0 (silence) and 1.0 (max amplitude).

-eca:peak-level-%, release_time, fastrate, rate

A more advanced compressor (original algorithm by John S. Dyson). If you give a value of 0 to any parameter, the default is used. 'peak-level-%' essentially specifies how hard the peak limiter is pushed. The default of 69% is good. 'release_time' is given in seconds. This compressor is very sophisticated, and actually the release time is complex. This is one of the dominant release time controls, but the actual release time is dependent on a lot of factors regarding the dynamics of the audio in. 'fastrate' is the compression ratio for the fast compressor. This is not really the compression ratio. Value of 1.0 is infinity to one, while the default 0.50 is 2:1. Another really good value is special cased in the code: 0.25 is somewhat less than 2:1, and sounds super smooth. 'rate' is the compression ratio for the entire compressor chain. The default is 1.0, and holds the volume very constant without many nasty side effects. However the dynamics in music are severely restricted, and a value of 0.5 might keep the music more intact.

-enm:threshold_level_%,th_time,attack,hold,release

Noise gate (mono-summed signal used to control the gate). When signal amplitude falls below 'threshold_level_%' percent (100% means maximum amplitude) the gate is activated. If the signal stays below the threshold for 'th_time' ms, it's faded out during the attack phase of 'attack' ms. If the signal raises above the 'threshold_level' and stays there over 'hold' ms the gate is released during 'release' ms.

-epp:right-%

Normal pan effect. Balance value of 0 means to pan signal fully left and 100 fully right. If the panned signal is a stereo signal, left and right channels aren't mixed together. Use the -f option to force conversion to mono before panning.

-ezx:left-dc-fix-value,right-dc-fix-value

Adjusts the signal DC by 'dc-fix-value'. Use -ezf to find the optimal value.

TIME-BASED EFFECTS

-etd:delay_time,surround-mode,number_of_delays,mix-%

Delay effect. 'delay time' is the delay time in milliseconds. 'surround-mode' is a integer with following meanings: 0 = normal, 1 = surround, 2 = stereo-spread. 'number_of_delays' should be obvious. Beware that large number of delays and huge delay times need a lot of CPU power. 'mix-%' determines how much effected (wet) signal is mixed to the original.

-etr:delay-time,surround-mode,feedback-%

Reverb effect. 'delay time' is the delay time in milliseconds. If 'surround-mode' is 'surround', reverbed signal moves around the stereo image. 'feedback-%' determines how much effected (wet) signal is fed back to the reverb.

-etf:delay_time

Fake-stereo effect. The input signal is summed to mono. The original signal goes to the left channels while a delayd version (with delay of 'delay time' milliseconds) is goes to the right. With a delay time of 1-40 milliseconds this adds a stereo-feel to mono-signals.

FILTER EFFECTS

-ef1:center_freq, width

Resonant bandpass filter. 'center_freq' is the center frequency. Width is specified in Hz.

-ef3:cutoff_freq, reso, gain

Resonant lowpass filter. 'cutoffr_freq' is the filter cutoff frequency. 'reso' means resonance. Usually the best values for resonance are between 1.0 and 2.0, but you can use even bigger values. 'gain' is the overall gain-factor. It's a simple multiplier (1.0 is the normal level). With high resonance values it often is useful to reduce the gain value.

-efb:center_freq,width

Bandpass filter. 'center_freq' is the center frequency. Width is specified in Hz.

-efh:cutoff_freq

Highpass filter. Only frequencies above 'cutoff_freq' are passed through.

-efi:delay_in_samples,radius

Inverse comb filter. Allows the spikes of the comb to pass through. The comb consists of 'delay_in_samples/2' spikes. The maximum value for 'radius' is 1.0. The closer it is to the maximum value, the deeper the dips of the comb.

-efl:cutoff_freq

Lowpass filter. Only frequencies below 'cutoff_freq' are passed through.

-efr:center_freq,width

Bandreject filter. 'center_freq' is the center frequency. Width is specified in Hz.

-efs:center_freq,width

Resonator. 'center_freq' is the center frequency. Width is specified in Hz. Basicly just another resonating bandpass filter.

GATE SETUP

-gc:start-time,len

Time crop gate. Initially gate is closed. After 'start-time' seconds has elapse, gate opens and remains open for 'len' seconds.

-ge:othreshold%, cthold%,volume_mode

Threshold gate. Initially gate is closed. It is opened when volume goes over 'othreshold' percent. After this, if volume drops below 'cthold' percent, gate is closed and won't be opened again. If 'value_mode' is 'rms', average RMS volume is used. Otherwise peak average is used.

CONTROL ENVELOPE SETUP

Controllers can be used to dynamically change effect parameters during processing. All controllers are attached to the active (=the last effect/chainop you specified) effect. The first three parameters are ommon for all controllers. 'fx_param' specifies the parameter to be controlled. Value '1' means the first parameter, '2' the second and so on. 'low_range' and 'high_range' set the value range. You really should see example.html for some more info.

-kos:fx_param,low_range,high_range,freq,i_phase

Sine oscillator with frequency of 'freq' Hz and initial phase of 'i_phase' times pi.

-kf:fx_param,low_range,high_range,genosc_number

Generic oscillator. 'genosc_number' is the number of the oscillator preset to be loaded. The location for the preset file is taken from ./ecasoundrc (see ecasoundrc(5).

-km:fx_param,low_range,high_range,controller,channel

MIDI continuous controller (control change messages). Messages on the MIDI-channel 'channel' that are coming from controller number 'controller' are used as the controller source. The MIDI-device is specified in ./ecasoundrc (see ecasoundrc(5). Defaults to /dev/midi.

INTERACTIVE MODE

The interactive mode of ecasound is launched with the -c option. In this mode, ecasound reacts to the following commands:

'quit', 'q'

Quits ecasound.

'exec'

Ecasound starts the processing engine. Normally you don't need to use this.

'end'

Ecasound exits the processing engine, but doesn't exit the interactive mode. Normally you don't need to use this.

'start', 't'

Processing is started (play).

'stop', 's'

Stops processing.

'debug debug-level'

Set debug level.

'rewind time-in-seconds', 'rw time-in-seconds'

Rewind the current position by 'time-in-seconds' seconds.

'forward time-in-seconds', 'fw time-in-seconds'

The current position is forwarded by 'time-in-seconds' seconds.

'setpos time-in-seconds'

Sets the current position to 'time-in-seconds' seconds from the beginning.

'status','st','u'

General status info.

'cstatus','cs','a'

Status info about the effect chains.

'estatus', 'es','x'

Status info about effects and controller envelopes.

'fstatus', 'fs','l'

Status info about open files and devices.

'sfx'

Enable/disable the sound effects section.

'chain chainname', 'c chainname'

Enable/disable the the chain 'chainname'.

'loop'

Start/stop looping.

'loop_start seconds_from_start'

Set the start point for looping.

loop_end seconds_from_start'

Set the end point for looping.

'load file_name'

Load a chainsetup from file 'file_name' and set it active.

'save file_name'

Save the active chainsetup to file 'file_name'.

'help', 'h'

Help!

FILES

~/.ecasoundrc The default ecasound resource file. See ecasoundrc(5) man page.

*.ews Ecasound Wave Stats. These files are used to cache waveform data.

SEE ALSO

qtecasound (1), ecatools (1), ecasoundrc(5), "HTML docs in the Documentation subdirectory"

BUGS

Lots of... ;) See the file BUGS. If ecasound behaves weirdly, try to increase the debug level to see what's going on.

AUTHOR

Kai Vehmanen, <kaiv@wakkanet.fi>