mqplot is a recent merger of the two original SNDAN programs
and mqdistr. These are also included in this version of SNDAN, for
the sake of completion, but are not included in this documentation set.
Unlike the much more comprehensive display program for .an format files,
provides no transformation facilities. It will display individual tracks
using either 2D or 3D co-ordinate displays, with the ability to 'project'
the net amplitude and frequency profiles to the respective axis plane.
A track can thus appear as an object in a 3-dimensional space, casting
a virtual shadow in two directions.
mqplot file.mq minf maxf dur [plot-type] [3D_flag] [start_time] [minamp] [maxamp]
file.mqThe name of the input .mq format analysis file.minfThe minimum frequency to plot (Hz). Should normally be at or below the analysis frequency for the file (use showhdr to find this if necessary). Set it higher if you want to zoom in on a frequency range of special interest.maxfThe maximum frequency to plot (Hz). The upper limit is the Nyquist rate for the analysed soundfile. Unless the sound is known to have prominent high frequency components, setting an upper limit between 2000 to 6000 Hz will display all significant tracks clearly.dur
In interactive mode, both minf and maxf are requested together.
The duration to plot (seconds), relative to start-time (which defaults to 0).
plot-type[Top]Type "2" for a 2D plot (frequency/ time), or "3" for a 3D plot (amplitude/frequency/time)3D-flagType 1 to activate projection dots, 0 to deactivate.start-time
The projection dots are used to cast a virtual shadow from tracks to either the amplitude and/or the frequency axis. They are most effective when the plot itself is fairly sparse. In other cases they can be difficult to distinguish from tracks, and are then best left deactivated.Use this to set a non-zero start-time (seconds) for the time axis - for example, to zoom in on the decay segment of a sound.minampSets the amplitude threshold (range 0 to 32767) for the display of partial tracks. Setting a non-zero value excludes low-level components that may be attributable to noise, or artefacts of the analysis. It can also be used to highlight the regions of the brightest timbre in the sound.maxampSets the maximum amplitude to plot, and hence the scale of the vertical axis.
Note: this is a required parameter for the 3D plot option only. If not included in the command line (which would therefore require all other optional parameters to be entered), it is asked for interactively.
h : (help) lists available commands
q or x : (quit) (exit) exit the program
2 : draw a 2D plot ( time/ frequency)
3 : draw a 3D (perspective) plot ( time/ frequency/amplitude)
requires an updated maxamp value each time
A : change display angles (3D only)a : change amplitude axis (3D only)requests two parameters, alpha and beta. Values are in degrees. alpha sets the angle (relative to horizontal) of the time axis. beta sets the angle (relative to the horizontal) of the frequency axis. Although the original documentation stipulates that alpha plus beta must not exceed 90, it has been found that so long as neither exceeds 90, the program works correctly. Some experimentation is worthwhile here, as the relationship between the given values and the appearance of the resulting display is not always obvious.
d : choose projection trace dots (3D only)v or f : change frequency scaleActivates and deactivates projection against the amplitude and frequency axes. Each axis is queried in turn; take care to activate the one you want!n or b : change frame axisenter the new values for minf and maxf (Hz)T : change time axisThe new start frame, and the number of frames to display, are required. A value for the latter can be found by experiment, or, for an accurate range, refer to the frame duration given in the analysis file header - this is displayed when the program is launched.t : change amplitude threshold. Corresponds to maxamp.start time and duration (seconds) are required.
u : update displayrepeat the plot with the current settings, in case you missed it the first time.
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