Tone

Tone (float "length", float "frequency", int "samplerate", int "channels", string "type", float "level")

This will generate sound (a waveform) at a given frequency for a given length of time in seconds. Type can be "Silence", "Sine" (default), "Noise", "Square", "Triangle" or "Sawtooth". level is the amplitude of the waveform (which is maximal if level=1.0).

Defaults are Tone(10.0, 440, 48000, 2, "sine", 1.0).

Tone(frequency=2, samplerate= 48000, channels= 2, type= "sine", level=0.4)

In the figure above, a sinus is generated (on a grey clip with framerate 24 fps). The period of the waveform (in frames) is the framerate divided by frequency (or fps/freq, which is 24/2=12 frames in our example). The part of the graph which is light-green represents all samples of the frame under consideration (which is frame 1 here). The number of samples in a particular frame is given by the samplerate divided by the framerate (which is 48000/24 = 2000 samples in our example). (Note that the bars are made with Histogram and the graph with the AudioGraph plugin.)

More generally, the waveform above is described by

g(n,s) = level * sin(2*pi*(frequency*n/framerate + s*frequency/samplerate))

with "n" the frame and "s" the sample under consideration (note that s runs from 0 to samplerate/framerate - 1).

In the example above, this reduces to

g(n,s) = 0.4 * sin(2*pi*(2*n/24 + s*2/48000))

with "n" the frame and "s" the sample under consideration (note that s runs from 0 to 1999).

Changes:

$Date: 2007/07/13 00:53:01 $