.TH "SDL_AudioSpec" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" 

.SH "NAME"

SDL_AudioSpec \- Audio Specification Structure

.SH "STRUCTURE DEFINITION"

.PP

.nf

\f(CWtypedef 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;\fR

.fi

.PP

.SH "STRUCTURE DATA"

.TP 20

\fBfreq\fR

Audio frequency in samples per second

.TP 20

\fBformat\fR

Audio data format

.TP 20

\fBchannels\fR

Number of channels: 1 mono, 2 stereo

.TP 20

\fBsilence\fR

Audio buffer silence value (calculated)

.TP 20

\fBsamples\fR

Audio buffer size in samples

.TP 20

\fBsize\fR

Audio buffer size in bytes (calculated)

.TP 20

\fBcallback(\&.\&.)\fR

Callback function for filling the audio buffer

.TP 20

\fBuserdata\fR

Pointer the user data which is passed to the callback function

.SH "DESCRIPTION"

.PP

The \fBSDL_AudioSpec\fR structure is used to describe the format of some audio data\&. This structure is used by \fI\fBSDL_OpenAudio\fP\fR and \fI\fBSDL_LoadWAV\fP\fR\&. While all fields are used by \fBSDL_OpenAudio\fP only \fBfreq\fR, \fBformat\fR, \fBsamples\fR and \fBchannels\fR are used by \fBSDL_LoadWAV\fP\&. We will detail these common members here\&.

.TP 20

\fBfreq\fR

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

.TP 20

\fBformat\fR

Specifies the size and type of each sample element 

.IP "\fBAUDIO_U8\fP" 10Unsigned 8-bit samples

.IP "\fBAUDIO_S8\fP" 10Signed 8-bit samples

.IP "\fBAUDIO_U16\fP or \fBAUDIO_U16LSB\fP" 10Unsigned 16-bit little-endian samples

.IP "\fBAUDIO_S16\fP or \fBAUDIO_S16LSB\fP" 10Signed 16-bit little-endian samples

.IP "\fBAUDIO_U16MSB\fP" 10Unsigned 16-bit big-endian samples

.IP "\fBAUDIO_S16MSB\fP" 10Signed 16-bit big-endian samples

.IP "\fBAUDIO_U16SYS\fP" 10Either \fBAUDIO_U16LSB\fP or \fBAUDIO_U16MSB\fP depending on you systems endianness

.IP "\fBAUDIO_S16SYS\fP" 10Either \fBAUDIO_S16LSB\fP or \fBAUDIO_S16MSB\fP depending on you systems endianness

.TP 20

\fBchannels\fR

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

.TP 20

\fBsamples\fR

When used with \fI\fBSDL_OpenAudio\fP\fR this refers to the size of the audio buffer in samples\&. A sample a chunk of audio data of the size specified in \fBformat\fR mulitplied by the number of channels\&. When the \fBSDL_AudioSpec\fR is used with \fI\fBSDL_LoadWAV\fP\fR \fBsamples\fR is set to 4096\&.

.SH "SEE ALSO"

.PP

\fI\fBSDL_OpenAudio\fP\fR, \fI\fBSDL_LoadWAV\fP\fR

...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58