| ActiveTcl User Guide |

### NAME

Snack_GetSampleRate, Snack_SetSampleRate, Snack_GetSampleEncoding, Snack_SetSampleEncoding, Snack_GetNumChannels, Snack_SetNumChannels, Snack_GetBytesPerSample, Snack_SetBytesPerSample, Snack_GetSoundFilename, Snack_SetHeaderSize - macros to set/get properties of Snack sound objects

### SYNOPSIS

#include <snack.h>
Snack_GetSampleRate(sound)
Snack_SetSampleRate(sound, frequency)
Snack_GetSampleEncoding(sound)
Snack_SetSampleEncoding(sound, format)
Snack_GetNumChannels(sound)
Snack_SetNumChannels(sound, numChannels)
Snack_GetBytesPerSample(sound)
Snack_SetBytesPerSample(sound, size)
Snack_SetHeaderSize(sound, size)
Snack_GetSoundFilename(sound)

### ARGUMENTS

Sound *sound (in)
A pointer to a sound object to query or modify
int frequency (in)
A positive integer specifying the sample rate of the sound.
int format (in)
An integer used to specify sample encoding format. Use one of these definitions LIN16, MULAW, ALAW, LIN8OFFSET, LIN8, LIN24, LIN32, SNACK_FLOAT, or SNACK_DOUBLE
int numChannels (in)
A positive integer specifying the number of separate channels of a sound
int size (in)
A size specification measured in bytes

### DESCRIPTION

The following functions are implemented as macros. Snack_GetLength returns the length of a sound in number of frames, for mono sounds this is equal to the number of samples. Snack_SetLength is used to specify the length of the sound. No storage is allocated/freed as a result of this, the function Snack_ResizeSoundStorage must be used to the perform actual storage management. Snack_GetFrequency and Snack_SetFrequency control the sampling frequency of a Snack sound object. Most audio devices only allow certain specific values for playback and recording. Common values are 8000, 11025, 16000, 22050, 32000, 44100, and 48000. Snack_GetNumChannels and Snack_SetNumChannels handle the number of channels of the sound, either a positive integer or MONO/STEREO/QUAD. Snack_GetSampleFormat and Snack_SetSampleFormat control the sample encoding format. Use the constants LIN16, MULAW, ALAW, LIN8OFFSET, LIN8, LIN24, LIN32, SNACK_FLOAT, or SNACK_DOUBLE. Snack_GetBytesPerSample and Snack_SetBytesPerSample should be used in conjunction with the previous pair. For LIN16 the number of bytes per sample is 2. No checks are performed for any arguments to these functions. Snack_GetSoundFilename is used to retrieve a pointer to the filename string which is or last was associated with the sound object. Snack_SetHeaderSize is used, in code that defines new sound file formats, to specify how large (in bytes) the header of the sound file is.