Name

SDL_AudioSpec — Audio Specification Structure

STRUCTURE DEFINITION

typedef struct {
  int   freq;  
  Uint16   format;  
  Uint8   channels;  
  Uint8   silence;  
  Uint16   samples;  
  Uint32   size;  
  void (* callback)(void *userdata, Uint8 *stream, int len);  
  void * userdata;  
} SDL_AudioSpec;

STRUCTURE DATA

freq

Audio frequency in samples per second

format

Audio data format

channels

Number of channels: 1 mono, 2 stereo

silence

Audio buffer silence value (calculated)

samples

Audio buffer size in samples

size

Audio buffer size in bytes (calculated)

callback(..)

Callback function for filling the audio buffer

userdata

Pointer the user data which is passed to the callback function

DESCRIPTION

The SDL_AudioSpec structure is used to describe the format of some audio data. This structure is used by SDL_OpenAudio and SDL_LoadWAV. While all fields are used by SDL_OpenAudio only freq, format, samples and channels are used by SDL_LoadWAV. We will detail these common members here.

freq

The number of samples sent to the sound device every second. Common values are 11025, 22050 and 44100. The higher the better.

format

Specifies the size and type of each sample element

AUDIO_U8
AUDIO_S8
AUDIO_U16 or AUDIO_U16LSB
AUDIO_S16 or AUDIO_S16LSB
AUDIO_U16MSB
AUDIO_S16MSB
AUDIO_U16SYS
AUDIO_S16SYS
channels

The number of seperate sound channels. 1 is mono (single channel), 2 is stereo (dual channel).

samples

When used with SDL_OpenAudio this refers to the size of the audio buffer in samples. A sample a chunk of audio data of the size specified in format mulitplied by the number of channels. When the SDL_AudioSpec is used with SDL_LoadWAV samples is set to 4096.

SEE ALSO

SDL_OpenAudio(3), SDL_LoadWAV(3)

COPYRIGHT

This manual page is taken from the SDL library, licensed under GNU LGPL.