# Tone

From Avisynth wiki

This will generate sound (a waveform) at a given frequency for a given length of time in seconds.

Tone( [ float *length*, float *frequency*, int *samplerate*, int *channels*, string *type*, float *level* ] )

*float*length =*10.0*

- Length of time in seconds.

*float*frequency =*440*

- Tone frequency.

*int*samplerate =*48000*

- Audio sample rate.

*int*channels =*2*

- Number of audio channels.

*string*type =*"Sine"*

- "Silence", "Sine", "Noise", "Square", "Triangle" or "Sawtooth".

*float*level =*1.0*

The audio sample type is **32-bit float**. Use ConvertAudio if this is not what you want.

#### Discussion

- In the figure above, a sinus is generated (on a gray 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).

- More generally, the waveform above is described by
*g*(*n,s*) =*level*(2**·**sin**·***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).

- Note that the bars are made with Histogram and the graph with the AudioGraph plugin.

#### Examples

*We Wish You a Merry Christmas*, in harmony (author hanzfrunz)

#### Changes

v2.56 | Added Level. |

v2.54 | Initial Release. |