(This is the legacy documentation for stable SDL2, the current stable version; SDL3 is the current development version.)

SDL_AudioSpec

The calculated values in this structure are calculated by SDL_OpenAudio().

Header File

Defined in [SDL_audio.h](https://github.com/libsdl-org/SDL/blob/SDL2/include/SDL_audio.h), but apps should _only_ `#include "SDL.h"`!

Syntax

typedef struct SDL_AudioSpec
{
    int freq;                   /**< DSP frequency -- samples per second */
    SDL_AudioFormat format;     /**< Audio data format */
    Uint8 channels;             /**< Number of channels: 1 mono, 2 stereo */
    Uint8 silence;              /**< Audio buffer silence value (calculated) */
    Uint16 samples;             /**< Audio buffer size in sample FRAMES (total samples divided by channel count) */
    Uint16 padding;             /**< Necessary for some compile environments */
    Uint32 size;                /**< Audio buffer size in bytes (calculated) */
    SDL_AudioCallback callback; /**< Callback that feeds the audio device (NULL to use SDL_QueueAudio()). */
    void *userdata;             /**< Userdata passed to callback (ignored for NULL callbacks). */
} SDL_AudioSpec;

Remarks

For multi-channel audio, the default SDL channel mapping is: 2: FL FR (stereo) 3: FL FR LFE (2.1 surround) 4: FL FR BL BR (quad) 5: FL FR LFE BL BR (4.1 surround) 6: FL FR FC LFE SL SR (5.1 surround - last two can also be BL BR) 7: FL FR FC LFE BC SL SR (6.1 surround) 8: FL FR FC LFE BL BR SL SR (7.1 surround)

Code Examples

SDL_AudioSpec want, have;
SDL_AudioDeviceID dev;

SDL_memset(&want, 0, sizeof(want)); /* or SDL_zero(want) */
want.freq = 48000;
want.format = AUDIO_F32;
want.channels = 2;
want.samples = 4096;
want.callback = MyAudioCallback;  // you wrote this function elsewhere.
dev = SDL_OpenAudioDevice(NULL, 0, &want, &have, SDL_AUDIO_ALLOW_FORMAT_CHANGE);

Data Fields

int	freq	DSP frequency (samples per second); see Remarks for details
SDL_AudioFormat	format	audio data format; see Remarks for details
Uint8	channels	number of separate sound channels: see Remarks for details
Uint8	silence	audio buffer silence value (calculated)
Uint16	samples	audio buffer size in samples (power of 2); see Remarks for details
Uint32	size	audio buffer size in bytes (calculated)
SDL_AudioCallback	callback	the function to call when the audio device needs more data; see Remarks for details
void*	userdata	a pointer that is passed to callback (otherwise ignored by SDL)

CategoryAPI, CategoryAPIStruct, CategoryStruct, CategoryAudio

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