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;| 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 |
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 +
|
| 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. |