The ToMono command takes multi-channel audio data and produces a single-channel monophonic audio object.

The ToStereo command takes single channel monophonic audio data and produces two-channel stereo audio (with corresponding samples in both channels having the same values). This is useful if a monophonic recording is to be combined in some way with a stereo recording.

The optional optNumChannels parameter of ToStereo can be used to specify that more than two channels are to be created. The number of channels must be a multiple of the number of input channels, and each input channel is repeated an appropriate number of times in the output.

The audArray parameter specifies the data to convert, and must be a dense, rectangular, one or two dimensional Array, Vector, or Matrix with datatype=float[8].

If either command is passed audio data that is already of the correct type, the audio data is returned. Otherwise, a new object of the appropriate type is created.

$\mathrm{audiofile}≔\mathrm{cat}\left(\mathrm{kernelopts}\left(\mathrm{datadir}\right)\,''/audio/stereo.wav''\right)\:$

$\mathrm{with}\left(\mathrm{AudioTools}\right)\:$

$\mathrm{aud}≔\mathrm{Read}\left(\mathrm{audiofile}\right)$

$\mathrm{aud}≔\left[\begin{array}{cc}''Sample\; Rate''& 22050\\ ''File\; Format''& \mathrm{PCM}\\ ''File\; Bit\; Depth''& 8\\ ''Channels''& 2\\ ''Samples/Channel''& 19962\\ ''Duration''& 0.90531s\end{array}\right]$

$\mathrm{aud}\left[2000\right]$

$\left[\begin{array}{cc}\mathrm{-0.312500000000000}& 0.771653543307087\end{array}\right]$

$\mathrm{mono}≔\mathrm{ToMono}\left(\mathrm{aud}\right)$

$\mathrm{mono}≔\left[\begin{array}{cc}''Sample\; Rate''& 22050\\ ''File\; Format''& \mathrm{PCM}\\ ''File\; Bit\; Depth''& 8\\ ''Channels''& 1\\ ''Samples/Channel''& 19962\\ ''Duration''& 0.90531s\end{array}\right]$

$\mathrm{mono}\left[2000\right]$

$0.229576771653543$

$\mathrm{stereo\_mono}≔\mathrm{ToStereo}\left(\mathrm{mono}\right)$

$\mathrm{stereo\_mono}≔\left[\begin{array}{cc}''Sample\; Rate''& 22050\\ ''File\; Format''& \mathrm{PCM}\\ ''File\; Bit\; Depth''& 8\\ ''Channels''& 2\\ ''Samples/Channel''& 19962\\ ''Duration''& 0.90531s\end{array}\right]$

$\mathrm{stereo\_mono}\left[2000\right]$

$\left[\begin{array}{cc}0.229576771653543& 0.229576771653543\end{array}\right]$

$\mathrm{quad\_stereo}≔\mathrm{ToStereo}\left(\mathrm{aud}\,4\right)$

$\mathrm{quad\_stereo}≔\left[\begin{array}{cc}''Sample\; Rate''& 22050\\ ''File\; Format''& \mathrm{PCM}\\ ''File\; Bit\; Depth''& 8\\ ''Channels''& 4\\ ''Samples/Channel''& 19962\\ ''Duration''& 0.90531s\end{array}\right]$

$\mathrm{quad\_stereo}\left[2000\right]$

$\left[\begin{array}{cccc}\mathrm{-0.312500000000000}& \mathrm{-0.312500000000000}& 0.771653543307087& 0.771653543307087\end{array}\right]$