SDL  2.0
SDL_audio.h File Reference
#include "SDL_stdinc.h"
#include "SDL_error.h"
#include "SDL_endian.h"
#include "SDL_mutex.h"
#include "SDL_thread.h"
#include "SDL_rwops.h"
#include "begin_code.h"
#include "close_code.h"
+ Include dependency graph for SDL_audio.h:
+ This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Data Structures

struct  SDL_AudioSpec
 
struct  SDL_AudioCVT
 

Macros

#define SDL_AUDIOCVT_PACKED
 
#define SDL_LoadWAV(file, spec, audio_buf, audio_len)   SDL_LoadWAV_RW(SDL_RWFromFile(file, "rb"),1, spec,audio_buf,audio_len)
 
#define SDL_MIX_MAXVOLUME   128
 
Audio flags
#define SDL_AUDIO_MASK_BITSIZE   (0xFF)
 
#define SDL_AUDIO_MASK_DATATYPE   (1<<8)
 
#define SDL_AUDIO_MASK_ENDIAN   (1<<12)
 
#define SDL_AUDIO_MASK_SIGNED   (1<<15)
 
#define SDL_AUDIO_BITSIZE(x)   (x & SDL_AUDIO_MASK_BITSIZE)
 
#define SDL_AUDIO_ISFLOAT(x)   (x & SDL_AUDIO_MASK_DATATYPE)
 
#define SDL_AUDIO_ISBIGENDIAN(x)   (x & SDL_AUDIO_MASK_ENDIAN)
 
#define SDL_AUDIO_ISSIGNED(x)   (x & SDL_AUDIO_MASK_SIGNED)
 
#define SDL_AUDIO_ISINT(x)   (!SDL_AUDIO_ISFLOAT(x))
 
#define SDL_AUDIO_ISLITTLEENDIAN(x)   (!SDL_AUDIO_ISBIGENDIAN(x))
 
#define SDL_AUDIO_ISUNSIGNED(x)   (!SDL_AUDIO_ISSIGNED(x))
 
Audio format flags

Defaults to LSB byte order.

#define AUDIO_U8   0x0008
 
#define AUDIO_S8   0x8008
 
#define AUDIO_U16LSB   0x0010
 
#define AUDIO_S16LSB   0x8010
 
#define AUDIO_U16MSB   0x1010
 
#define AUDIO_S16MSB   0x9010
 
#define AUDIO_U16   AUDIO_U16LSB
 
#define AUDIO_S16   AUDIO_S16LSB
 
int32 support
#define AUDIO_S32LSB   0x8020
 
#define AUDIO_S32MSB   0x9020
 
#define AUDIO_S32   AUDIO_S32LSB
 
float32 support
#define AUDIO_F32LSB   0x8120
 
#define AUDIO_F32MSB   0x9120
 
#define AUDIO_F32   AUDIO_F32LSB
 
Native audio byte ordering
#define AUDIO_U16SYS   AUDIO_U16LSB
 
#define AUDIO_S16SYS   AUDIO_S16LSB
 
#define AUDIO_S32SYS   AUDIO_S32LSB
 
#define AUDIO_F32SYS   AUDIO_F32LSB
 
Allow change flags

Which audio format changes are allowed when opening a device.

#define SDL_AUDIO_ALLOW_FREQUENCY_CHANGE   0x00000001
 
#define SDL_AUDIO_ALLOW_FORMAT_CHANGE   0x00000002
 
#define SDL_AUDIO_ALLOW_CHANNELS_CHANGE   0x00000004
 
#define SDL_AUDIO_ALLOW_ANY_CHANGE   (SDL_AUDIO_ALLOW_FREQUENCY_CHANGE|SDL_AUDIO_ALLOW_FORMAT_CHANGE|SDL_AUDIO_ALLOW_CHANNELS_CHANGE)
 

Typedefs

typedef Uint16 SDL_AudioFormat
 Audio format flags. More...
 
typedef void(* SDL_AudioCallback) (void *userdata, Uint8 *stream, int len)
 
typedef void(* SDL_AudioFilter) (struct SDL_AudioCVT *cvt, SDL_AudioFormat format)
 
typedef Uint32 SDL_AudioDeviceID
 

Functions

const char * SDL_GetCurrentAudioDriver (void)
 
int SDL_OpenAudio (SDL_AudioSpec *desired, SDL_AudioSpec *obtained)
 
int SDL_GetNumAudioDevices (int iscapture)
 
const char * SDL_GetAudioDeviceName (int index, int iscapture)
 
SDL_AudioDeviceID SDL_OpenAudioDevice (const char *device, int iscapture, const SDL_AudioSpec *desired, SDL_AudioSpec *obtained, int allowed_changes)
 
SDL_AudioSpecSDL_LoadWAV_RW (SDL_RWops *src, int freesrc, SDL_AudioSpec *spec, Uint8 **audio_buf, Uint32 *audio_len)
 
void SDL_FreeWAV (Uint8 *audio_buf)
 
int SDL_BuildAudioCVT (SDL_AudioCVT *cvt, SDL_AudioFormat src_format, Uint8 src_channels, int src_rate, SDL_AudioFormat dst_format, Uint8 dst_channels, int dst_rate)
 
int SDL_ConvertAudio (SDL_AudioCVT *cvt)
 
void SDL_MixAudio (Uint8 *dst, const Uint8 *src, Uint32 len, int volume)
 
void SDL_MixAudioFormat (Uint8 *dst, const Uint8 *src, SDL_AudioFormat format, Uint32 len, int volume)
 
int SDL_QueueAudio (SDL_AudioDeviceID dev, const void *data, Uint32 len)
 
Uint32 SDL_GetQueuedAudioSize (SDL_AudioDeviceID dev)
 
void SDL_ClearQueuedAudio (SDL_AudioDeviceID dev)
 
void SDL_CloseAudio (void)
 
void SDL_CloseAudioDevice (SDL_AudioDeviceID dev)
 
Driver discovery functions

These functions return the list of built in audio drivers, in the order that they are normally initialized by default.

int SDL_GetNumAudioDrivers (void)
 
const char * SDL_GetAudioDriver (int index)
 
Initialization and cleanup

These functions are used internally, and should not be used unless you have a specific need to specify the audio driver you want to use. You should normally use SDL_Init() or SDL_InitSubSystem().

int SDL_AudioInit (const char *driver_name)
 
void SDL_AudioQuit (void)
 
Pause audio functions

These functions pause and unpause the audio callback processing. They should be called with a parameter of 0 after opening the audio device to start playing sound. This is so you can safely initialize data for your callback function after opening the audio device. Silence will be written to the audio device during the pause.

void SDL_PauseAudio (int pause_on)
 
void SDL_PauseAudioDevice (SDL_AudioDeviceID dev, int pause_on)
 
Audio lock functions

The lock manipulated by these functions protects the callback function. During a SDL_LockAudio()/SDL_UnlockAudio() pair, you can be guaranteed that the callback function is not running. Do not call these from the callback function or you will cause deadlock.

void SDL_LockAudio (void)
 
void SDL_LockAudioDevice (SDL_AudioDeviceID dev)
 
void SDL_UnlockAudio (void)
 
void SDL_UnlockAudioDevice (SDL_AudioDeviceID dev)
 

Audio state

Get the current audio state.

enum  SDL_AudioStatus {
  SDL_AUDIO_STOPPED = 0,
  SDL_AUDIO_PLAYING,
  SDL_AUDIO_PAUSED
}
 
SDL_AudioStatus SDL_GetAudioStatus (void)
 
SDL_AudioStatus SDL_GetAudioDeviceStatus (SDL_AudioDeviceID dev)
 

Detailed Description

Access to the raw audio mixing buffer for the SDL library.

Definition in file SDL_audio.h.

Macro Definition Documentation

#define AUDIO_F32   AUDIO_F32LSB
#define AUDIO_F32SYS   AUDIO_F32LSB

Definition at line 125 of file SDL_audio.h.

Referenced by audio_initOpenCloseQuitAudio(), and audio_pauseUnpauseAudio().

#define AUDIO_S32   AUDIO_S32LSB
#define AUDIO_S32SYS   AUDIO_S32LSB

Definition at line 124 of file SDL_audio.h.

#define AUDIO_U16   AUDIO_U16LSB
#define AUDIO_U16SYS   AUDIO_U16LSB

Definition at line 122 of file SDL_audio.h.

#define SDL_AUDIO_ALLOW_CHANNELS_CHANGE   0x00000004

Definition at line 142 of file SDL_audio.h.

Referenced by open_audio_device().

#define SDL_AUDIO_ALLOW_FORMAT_CHANGE   0x00000002

Definition at line 141 of file SDL_audio.h.

Referenced by open_audio_device().

#define SDL_AUDIO_ALLOW_FREQUENCY_CHANGE   0x00000001

Definition at line 140 of file SDL_audio.h.

Referenced by open_audio_device().

#define SDL_AUDIO_ISBIGENDIAN (   x)    (x & SDL_AUDIO_MASK_ENDIAN)

Definition at line 77 of file SDL_audio.h.

Referenced by SDL_ConvertMono(), SDL_ConvertSurround(), and SDL_ConvertSurround_4().

#define SDL_AUDIO_ISFLOAT (   x)    (x & SDL_AUDIO_MASK_DATATYPE)

Definition at line 76 of file SDL_audio.h.

#define SDL_AUDIO_ISINT (   x)    (!SDL_AUDIO_ISFLOAT(x))

Definition at line 79 of file SDL_audio.h.

#define SDL_AUDIO_ISLITTLEENDIAN (   x)    (!SDL_AUDIO_ISBIGENDIAN(x))

Definition at line 80 of file SDL_audio.h.

#define SDL_AUDIO_ISSIGNED (   x)    (x & SDL_AUDIO_MASK_SIGNED)

Definition at line 78 of file SDL_audio.h.

Referenced by SDL_BuildAudioCVT().

#define SDL_AUDIO_ISUNSIGNED (   x)    (!SDL_AUDIO_ISSIGNED(x))

Definition at line 81 of file SDL_audio.h.

#define SDL_AUDIO_MASK_BITSIZE   (0xFF)

Definition at line 71 of file SDL_audio.h.

Referenced by SDL_ConvertMono(), SDL_ConvertSurround(), and SDL_ConvertSurround_4().

#define SDL_AUDIO_MASK_DATATYPE   (1<<8)

Definition at line 72 of file SDL_audio.h.

Referenced by SDL_ConvertMono(), SDL_ConvertSurround(), and SDL_ConvertSurround_4().

#define SDL_AUDIO_MASK_ENDIAN   (1<<12)

Definition at line 73 of file SDL_audio.h.

#define SDL_AUDIO_MASK_SIGNED   (1<<15)

Definition at line 74 of file SDL_audio.h.

Referenced by SDL_ConvertMono(), SDL_ConvertSurround(), and SDL_ConvertSurround_4().

#define SDL_AUDIOCVT_PACKED

A structure to hold a set of audio conversion filters and buffers.

Definition at line 197 of file SDL_audio.h.

#define SDL_LoadWAV (   file,
  spec,
  audio_buf,
  audio_len 
)    SDL_LoadWAV_RW(SDL_RWFromFile(file, "rb"),1, spec,audio_buf,audio_len)

Loads a WAV from a file. Compatibility convenience function.

Definition at line 424 of file SDL_audio.h.

Referenced by main().

#define SDL_MIX_MAXVOLUME   128

Definition at line 461 of file SDL_audio.h.

Referenced by SDL_MixAudioFormat().

Typedef Documentation

typedef void( * SDL_AudioCallback) (void *userdata, Uint8 *stream, int len)

This function is called when the audio device needs more data.

Parameters
userdataAn application-specific parameter saved in the SDL_AudioSpec structure
streamA pointer to the audio data buffer.
lenThe length of that buffer in bytes.

Once the callback returns, the buffer will no longer be valid. Stereo samples are stored in a LRLRLR ordering.

You can choose to avoid callbacks and use SDL_QueueAudio() instead, if you like. Just open your audio device with a NULL callback.

Definition at line 162 of file SDL_audio.h.

SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char const char SDL_SCANF_FORMAT_STRING const char return SDL_ThreadFunction const char void return Uint32 return Uint32 SDL_AssertionHandler void SDL_SpinLock SDL_atomic_t int int return SDL_atomic_t return void void void return void return int return SDL_AudioSpec SDL_AudioSpec return int int return return int SDL_RWops int SDL_AudioSpec Uint8 Uint32 return SDL_AudioCVT SDL_AudioFormat Uint8 int SDL_AudioFormat Uint8 int return Uint8 const Uint8 Uint32 int const char return return return return return return return return Uint32 return Uint32 SDL_Event return SDL_Event int return SDL_EventFilter void SDL_EventFilter void SDL_EventFilter void int return const char const char return SDL_JoystickGUID return int return int return SDL_GameController return int return const char return SDL_GameController SDL_GameControllerAxis return const char return SDL_GameController SDL_GameControllerButton return SDL_GameController SDL_RWops return SDL_TouchID SDL_RWops return int return int return return SDL_Joystick return SDL_Haptic SDL_Haptic return SDL_Haptic return SDL_Haptic SDL_HapticEffect return SDL_Haptic int Uint32 return SDL_Haptic int SDL_Haptic int return SDL_Haptic return SDL_Haptic return SDL_Haptic return SDL_Haptic return const char const char return const char SDL_HintCallback void int return SDL_Joystick return SDL_Joystick return const char return SDL_Joystick return SDL_Joystick return SDL_Joystick return int return SDL_Joystick int return SDL_Joystick int return return return SDL_Scancode return SDL_Scancode return SDL_Keycode return return const char return void int SDL_LogPriority SDL_LogOutputFunction void Uint32 const char const char SDL_Window return int int return SDL_Window int int return SDL_Surface int int return SDL_Cursor return int return SDL_mutex return SDL_mutex return Uint32 return SDL_sem return SDL_sem Uint32 return SDL_sem return SDL_cond SDL_cond return SDL_cond SDL_mutex Uint32 return Uint32 int Uint32 Uint32 Uint32 Uint32 return Uint32 return int return SDL_Palette const SDL_Color int int return const SDL_PixelFormat Uint8 Uint8 Uint8 return Uint32 const SDL_PixelFormat Uint8 Uint8 Uint8 float Uint16 int int return const SDL_Rect const SDL_Rect SDL_Rect return const SDL_Point int const SDL_Rect SDL_Rect return return int int Uint32 SDL_Window SDL_Renderer return SDL_Surface return SDL_Renderer SDL_RendererInfo return SDL_Renderer Uint32 int int int return SDL_Texture Uint32 int int int return SDL_Texture Uint8 Uint8 Uint8 return SDL_Texture Uint8 return SDL_Texture SDL_BlendMode return SDL_Texture const SDL_Rect const Uint8 int const Uint8 int const Uint8 int return SDL_Texture SDL_Renderer SDL_Texture return SDL_Renderer int int return SDL_Renderer const SDL_Rect return SDL_Renderer const SDL_Rect return SDL_Renderer float float return SDL_Renderer Uint8 Uint8 Uint8 Uint8 return SDL_Renderer SDL_BlendMode return SDL_Renderer return SDL_Renderer const SDL_Point int return SDL_Renderer const SDL_Point int return SDL_Renderer const SDL_Rect int return SDL_Renderer const SDL_Rect int return SDL_Renderer SDL_Texture const SDL_Rect const SDL_Rect const double const SDL_Point const SDL_RendererFlip return SDL_Renderer SDL_Renderer SDL_Texture return void int return return SDL_RWops return SDL_RWops return SDL_RWops return SDL_RWops return SDL_RWops Uint16 return SDL_RWops Uint32 return SDL_RWops Uint64 return const char unsigned int unsigned int unsigned int unsigned int Uint32 return SDL_Window SDL_Surface SDL_WindowShapeMode return size_t return void size_t return const char return void size_t size_t int(*) SDL_DYNAPI_PROC int return int return int size_t return size_t return const wchar_t return const wchar_t size_t return const char size_t return const char size_t return char return char return const char int return int char int return long char int return Sint64 char int return const char return const char char int return const char char int return const char char return const char const char size_t return const char const char size_t return double return double return double return double return double return double return double int return float return const char const char return SDL_iconv_t const char size_t char size_t return Uint32 int int int Uint32 Uint32 Uint32 Uint32 return SDL_Surface SDL_Surface return SDL_RWops int return SDL_Surface int return SDL_Surface Uint32 return SDL_Surface Uint8 Uint8 Uint8 return SDL_Surface Uint8 return SDL_Surface SDL_BlendMode return SDL_Surface SDL_Rect SDL_Surface Uint32 Uint32 return SDL_Surface const SDL_Rect Uint32 return SDL_Surface const SDL_Rect SDL_Surface SDL_Rect return SDL_Surface const SDL_Rect SDL_Surface const SDL_Rect return SDL_Surface SDL_Rect SDL_Surface SDL_Rect return SDL_Thread return SDL_Thread return SDL_Thread int return SDL_TLSID const void void(*) return return Uint32 SDL_TimerID return int return SDL_TouchID int return return return const char return return int return int return int SDL_DisplayMode return int const SDL_DisplayMode SDL_DisplayMode return SDL_Window const SDL_DisplayMode return SDL_Window return const void return Uint32 return SDL_Window const char SDL_Window SDL_Surface SDL_Window const char return SDL_Window int int SDL_Window int int SDL_Window int int SDL_Window int int SDL_Window SDL_Window SDL_Window SDL_Window Uint32 return SDL_Window return SDL_Window SDL_bool SDL_Window float return SDL_Window const Uint16 const Uint16 const Uint16 return SDL_Window const char return SDL_GLattr int return SDL_Window return return SDL_Window int int return SDL_GLContext SDL_RWops int return return void return int int return double return SDL_bool return int int return SDL_AudioDeviceID const void Uint32 return SDL_AudioDeviceID(SDL_Window *, SDL_GetGrabbedWindow,(void),(), return) SDL_DYNAPI_PROC(int

SDL Audio Device IDs.

A successful call to SDL_OpenAudio() is always device id 1, and legacy SDL audio APIs assume you want this device ID. SDL_OpenAudioDevice() calls always returns devices >= 2 on success. The legacy calls are good both for backwards compatibility and when you don't care about multiple, specific, or capture devices.

Definition at line 303 of file SDL_audio.h.

typedef void( * SDL_AudioFilter) (struct SDL_AudioCVT *cvt, SDL_AudioFormat format)

Definition at line 183 of file SDL_audio.h.

Audio format flags.

These are what the 16 bits in SDL_AudioFormat currently mean... (Unspecified bits are always zero).

++-----------------------sample is signed if set
||
||       ++-----------sample is bigendian if set
||       ||
||       ||          ++---sample is float if set
||       ||          ||
||       ||          || +---sample bit size---+
||       ||          || |                     |
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

There are macros in SDL 2.0 and later to query these bits.

Definition at line 64 of file SDL_audio.h.

Enumeration Type Documentation

Enumerator
SDL_AUDIO_STOPPED 
SDL_AUDIO_PLAYING 
SDL_AUDIO_PAUSED 

Definition at line 368 of file SDL_audio.h.

Function Documentation

int SDL_AudioInit ( const char *  driver_name)

Definition at line 711 of file SDL_audio.c.

References AudioBootStrap::demand_only, SDL_AudioDriver::desc, AudioBootStrap::desc, SDL_AudioDriverImpl::DetectDevices, SDL_AudioDriver::detectionLock, finalize_audio_entry_points(), i, SDL_AudioDriver::impl, AudioBootStrap::init, SDL_AudioDriver::name, AudioBootStrap::name, NULL, SDL_AudioQuit(), SDL_CreateMutex, SDL_getenv, SDL_INIT_AUDIO, SDL_SetError, SDL_strlen, SDL_strncasecmp, SDL_WasInit, and SDL_zero.

712 {
713  int i = 0;
714  int initialized = 0;
715  int tried_to_init = 0;
716 
718  SDL_AudioQuit(); /* shutdown driver if already running. */
719  }
720 
723 
724  /* Select the proper audio driver */
725  if (driver_name == NULL) {
726  driver_name = SDL_getenv("SDL_AUDIODRIVER");
727  }
728 
729  for (i = 0; (!initialized) && (bootstrap[i]); ++i) {
730  /* make sure we should even try this driver before doing so... */
731  const AudioBootStrap *backend = bootstrap[i];
732  if ((driver_name && (SDL_strncasecmp(backend->name, driver_name, SDL_strlen(driver_name)) != 0)) ||
733  (!driver_name && backend->demand_only)) {
734  continue;
735  }
736 
737  tried_to_init = 1;
739  current_audio.name = backend->name;
740  current_audio.desc = backend->desc;
741  initialized = backend->init(&current_audio.impl);
742  }
743 
744  if (!initialized) {
745  /* specific drivers will set the error message if they fail... */
746  if (!tried_to_init) {
747  if (driver_name) {
748  SDL_SetError("Audio target '%s' not available", driver_name);
749  } else {
750  SDL_SetError("No available audio device");
751  }
752  }
753 
755  return -1; /* No driver was available, so fail. */
756  }
757 
759 
761 
762  /* Make sure we have a list of devices available at startup. */
764 
765  return 0;
766 }
static SDL_AudioDevice * open_devices[16]
Definition: SDL_audio.c:34
const char * name
Definition: SDL_sysaudio.h:114
void(* DetectDevices)(void)
Definition: SDL_sysaudio.h:71
const char * name
Definition: SDL_sysaudio.h:191
#define SDL_CreateMutex
static SDL_AudioDriver current_audio
Definition: SDL_audio.c:33
#define SDL_strncasecmp
static void finalize_audio_entry_points(void)
Definition: SDL_audio.c:262
SDL_mutex * detectionLock
Definition: SDL_sysaudio.h:123
const char * desc
Definition: SDL_sysaudio.h:118
void SDL_AudioQuit(void)
Definition: SDL_audio.c:1345
#define SDL_zero(x)
Definition: SDL_stdinc.h:355
#define SDL_getenv
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display Drawable _Xconst char unsigned int unsigned int return Display Pixmap Pixmap XColor XColor unsigned int unsigned int return Display _Xconst char char int char return Display Visual unsigned int int int char unsigned int unsigned int in i)
Definition: SDL_x11sym.h:42
static const AudioBootStrap *const bootstrap[]
Definition: SDL_audio.c:76
#define NULL
Definition: begin_code.h:143
#define SDL_SetError
#define SDL_INIT_AUDIO
Definition: SDL.h:76
SDL_AudioDriverImpl impl
Definition: SDL_sysaudio.h:120
#define SDL_strlen
int(* init)(SDL_AudioDriverImpl *impl)
Definition: SDL_sysaudio.h:193
const char * desc
Definition: SDL_sysaudio.h:192
#define SDL_WasInit
void SDL_AudioQuit ( void  )

Definition at line 1345 of file SDL_audio.c.

References SDL_AudioDriverImpl::Deinitialize, SDL_AudioDriver::detectionLock, free_device_list(), i, SDL_AudioDriver::impl, SDL_AudioDriver::inputDeviceCount, SDL_AudioDriver::inputDevices, SDL_AudioDriver::name, NULL, SDL_AudioDriver::outputDeviceCount, SDL_AudioDriver::outputDevices, SDL_arraysize, SDL_CloseAudioDevice(), SDL_DestroyMutex, and SDL_zero.

Referenced by SDL_AudioInit().

1346 {
1348 
1349  if (!current_audio.name) { /* not initialized?! */
1350  return;
1351  }
1352 
1353  for (i = 0; i < SDL_arraysize(open_devices); i++) {
1354  if (open_devices[i] != NULL) {
1355  SDL_CloseAudioDevice(i+1);
1356  }
1357  }
1358 
1361 
1362  /* Free the driver data */
1364 
1366 
1369 }
static SDL_AudioDevice * open_devices[16]
Definition: SDL_audio.c:34
const char * name
Definition: SDL_sysaudio.h:114
static SDL_AudioDriver current_audio
Definition: SDL_audio.c:33
SDL_mutex * detectionLock
Definition: SDL_sysaudio.h:123
void(* Deinitialize)(void)
Definition: SDL_sysaudio.h:83
#define SDL_zero(x)
Definition: SDL_stdinc.h:355
SDL_AudioDeviceItem * outputDevices
Definition: SDL_sysaudio.h:128
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display Drawable _Xconst char unsigned int unsigned int return Display Pixmap Pixmap XColor XColor unsigned int unsigned int return Display _Xconst char char int char return Display Visual unsigned int int int char unsigned int unsigned int in i)
Definition: SDL_x11sym.h:42
#define NULL
Definition: begin_code.h:143
static void free_device_list(SDL_AudioDeviceItem **devices, int *devCount)
Definition: SDL_audio.c:330
#define SDL_DestroyMutex
Uint32 SDL_AudioDeviceID
Definition: SDL_audio.h:303
SDL_AudioDriverImpl impl
Definition: SDL_sysaudio.h:120
#define SDL_arraysize(array)
Definition: SDL_stdinc.h:93
void SDL_CloseAudioDevice(SDL_AudioDeviceID devid)
Definition: SDL_audio.c:1329
SDL_AudioDeviceItem * inputDevices
Definition: SDL_sysaudio.h:129
int SDL_BuildAudioCVT ( SDL_AudioCVT cvt,
SDL_AudioFormat  src_format,
Uint8  src_channels,
int  src_rate,
SDL_AudioFormat  dst_format,
Uint8  dst_channels,
int  dst_rate 
)

This function takes a source format and rate and a destination format and rate, and initializes the cvt structure with information needed by SDL_ConvertAudio() to convert a buffer of audio data from one format to the other.

Returns
-1 if the format conversion is not supported, 0 if there's no conversion needed, or 1 if the audio filter is set up.

Definition at line 998 of file SDL_audiocvt.c.

References SDL_AudioCVT::buf, SDL_AudioCVT::dst_format, SDL_AudioCVT::filter_index, SDL_AudioCVT::filters, SDL_AudioCVT::len, SDL_AudioCVT::len_mult, SDL_AudioCVT::len_ratio, SDL_AudioCVT::needed, NULL, SDL_AudioCVT::rate_incr, SDL_AUDIO_BITSIZE, SDL_AUDIO_ISSIGNED, SDL_BuildAudioResampleCVT(), SDL_BuildAudioTypeCVT(), SDL_ConvertMono(), SDL_ConvertStereo(), SDL_ConvertStrip(), SDL_ConvertStrip_2(), SDL_ConvertSurround(), SDL_ConvertSurround_4(), SDL_InvalidParamError, SDL_SetError, SDL_zerop, and SDL_AudioCVT::src_format.

1001 {
1002  /*
1003  * !!! FIXME: reorder filters based on which grow/shrink the buffer.
1004  * !!! FIXME: ideally, we should do everything that shrinks the buffer
1005  * !!! FIXME: first, so we don't have to process as many bytes in a given
1006  * !!! FIXME: filter and abuse the CPU cache less. This might not be as
1007  * !!! FIXME: good in practice as it sounds in theory, though.
1008  */
1009 
1010  /* Sanity check target pointer */
1011  if (cvt == NULL) {
1012  return SDL_InvalidParamError("cvt");
1013  }
1014 
1015  /* there are no unsigned types over 16 bits, so catch this up front. */
1016  if ((SDL_AUDIO_BITSIZE(src_fmt) > 16) && (!SDL_AUDIO_ISSIGNED(src_fmt))) {
1017  return SDL_SetError("Invalid source format");
1018  }
1019  if ((SDL_AUDIO_BITSIZE(dst_fmt) > 16) && (!SDL_AUDIO_ISSIGNED(dst_fmt))) {
1020  return SDL_SetError("Invalid destination format");
1021  }
1022 
1023  /* prevent possible divisions by zero, etc. */
1024  if ((src_channels == 0) || (dst_channels == 0)) {
1025  return SDL_SetError("Source or destination channels is zero");
1026  }
1027  if ((src_rate == 0) || (dst_rate == 0)) {
1028  return SDL_SetError("Source or destination rate is zero");
1029  }
1030 #ifdef DEBUG_CONVERT
1031  printf("Build format %04x->%04x, channels %u->%u, rate %d->%d\n",
1032  src_fmt, dst_fmt, src_channels, dst_channels, src_rate, dst_rate);
1033 #endif
1034 
1035  /* Start off with no conversion necessary */
1036  SDL_zerop(cvt);
1037  cvt->src_format = src_fmt;
1038  cvt->dst_format = dst_fmt;
1039  cvt->needed = 0;
1040  cvt->filter_index = 0;
1041  cvt->filters[0] = NULL;
1042  cvt->len_mult = 1;
1043  cvt->len_ratio = 1.0;
1044  cvt->rate_incr = ((double) dst_rate) / ((double) src_rate);
1045 
1046  /* Convert data types, if necessary. Updates (cvt). */
1047  if (SDL_BuildAudioTypeCVT(cvt, src_fmt, dst_fmt) == -1) {
1048  return -1; /* shouldn't happen, but just in case... */
1049  }
1050 
1051  /* Channel conversion */
1052  if (src_channels != dst_channels) {
1053  if ((src_channels == 1) && (dst_channels > 1)) {
1054  cvt->filters[cvt->filter_index++] = SDL_ConvertStereo;
1055  cvt->len_mult *= 2;
1056  src_channels = 2;
1057  cvt->len_ratio *= 2;
1058  }
1059  if ((src_channels == 2) && (dst_channels == 6)) {
1060  cvt->filters[cvt->filter_index++] = SDL_ConvertSurround;
1061  src_channels = 6;
1062  cvt->len_mult *= 3;
1063  cvt->len_ratio *= 3;
1064  }
1065  if ((src_channels == 2) && (dst_channels == 4)) {
1067  src_channels = 4;
1068  cvt->len_mult *= 2;
1069  cvt->len_ratio *= 2;
1070  }
1071  while ((src_channels * 2) <= dst_channels) {
1072  cvt->filters[cvt->filter_index++] = SDL_ConvertStereo;
1073  cvt->len_mult *= 2;
1074  src_channels *= 2;
1075  cvt->len_ratio *= 2;
1076  }
1077  if ((src_channels == 6) && (dst_channels <= 2)) {
1078  cvt->filters[cvt->filter_index++] = SDL_ConvertStrip;
1079  src_channels = 2;
1080  cvt->len_ratio /= 3;
1081  }
1082  if ((src_channels == 6) && (dst_channels == 4)) {
1083  cvt->filters[cvt->filter_index++] = SDL_ConvertStrip_2;
1084  src_channels = 4;
1085  cvt->len_ratio /= 2;
1086  }
1087  /* This assumes that 4 channel audio is in the format:
1088  Left {front/back} + Right {front/back}
1089  so converting to L/R stereo works properly.
1090  */
1091  while (((src_channels % 2) == 0) &&
1092  ((src_channels / 2) >= dst_channels)) {
1093  cvt->filters[cvt->filter_index++] = SDL_ConvertMono;
1094  src_channels /= 2;
1095  cvt->len_ratio /= 2;
1096  }
1097  if (src_channels != dst_channels) {
1098  /* Uh oh.. */ ;
1099  }
1100  }
1101 
1102  /* Do rate conversion, if necessary. Updates (cvt). */
1103  if (SDL_BuildAudioResampleCVT(cvt, dst_channels, src_rate, dst_rate) ==
1104  -1) {
1105  return -1; /* shouldn't happen, but just in case... */
1106  }
1107 
1108  /* Set up the filter information */
1109  if (cvt->filter_index != 0) {
1110  cvt->needed = 1;
1111  cvt->src_format = src_fmt;
1112  cvt->dst_format = dst_fmt;
1113  cvt->len = 0;
1114  cvt->buf = NULL;
1115  cvt->filters[cvt->filter_index] = NULL;
1116  }
1117  return (cvt->needed);
1118 }
Uint8 * buf
Definition: SDL_audio.h:206
int filter_index
Definition: SDL_audio.h:212
double len_ratio
Definition: SDL_audio.h:210
#define SDL_AUDIO_ISSIGNED(x)
Definition: SDL_audio.h:78
#define SDL_InvalidParamError(param)
Definition: SDL_error.h:54
#define SDL_zerop(x)
Definition: SDL_stdinc.h:356
static int SDL_BuildAudioResampleCVT(SDL_AudioCVT *cvt, int dst_channels, int src_rate, int dst_rate)
Definition: SDL_audiocvt.c:944
static void SDL_ConvertStrip_2(SDL_AudioCVT *cvt, SDL_AudioFormat format)
Definition: SDL_audiocvt.c:239
SDL_AudioFilter filters[10]
Definition: SDL_audio.h:211
#define SDL_AUDIO_BITSIZE(x)
Definition: SDL_audio.h:75
SDL_AudioFormat src_format
Definition: SDL_audio.h:203
static void SDL_ConvertSurround(SDL_AudioCVT *cvt, SDL_AudioFormat format)
Definition: SDL_audiocvt.c:328
#define NULL
Definition: begin_code.h:143
static void SDL_ConvertStereo(SDL_AudioCVT *cvt, SDL_AudioFormat format)
Definition: SDL_audiocvt.c:285
#define SDL_SetError
SDL_AudioFormat dst_format
Definition: SDL_audio.h:204
static void SDL_ConvertSurround_4(SDL_AudioCVT *cvt, SDL_AudioFormat format)
Definition: SDL_audiocvt.c:587
double rate_incr
Definition: SDL_audio.h:205
static void SDL_ConvertMono(SDL_AudioCVT *cvt, SDL_AudioFormat format)
Definition: SDL_audiocvt.c:34
static void SDL_ConvertStrip(SDL_AudioCVT *cvt, SDL_AudioFormat format)
Definition: SDL_audiocvt.c:195
static int SDL_BuildAudioTypeCVT(SDL_AudioCVT *cvt, SDL_AudioFormat src_fmt, SDL_AudioFormat dst_fmt)
Definition: SDL_audiocvt.c:856
void SDL_ClearQueuedAudio ( SDL_AudioDeviceID  dev)

Drop any queued audio data waiting to be sent to the hardware.

Immediately after this call, SDL_GetQueuedAudioSize() will return 0 and the hardware will start playing silence if more audio isn't queued.

This will not prevent playback of queued audio that's already been sent to the hardware, as we can not undo that, so expect there to be some fraction of a second of audio that might still be heard. This can be useful if you want to, say, drop any pending music during a level change in your game.

You may not queue audio on a device that is using an application-supplied callback; calling this function on such a device is always a no-op. You have to use the audio callback or queue audio with SDL_QueueAudio(), but not both.

You should not call SDL_LockAudio() on the device before clearing the queue; SDL handles locking internally for this function.

This function always succeeds and thus returns void.

Parameters
devThe device ID of which to clear the audio queue.
See also
SDL_QueueAudio
SDL_GetQueuedAudioSize

Definition at line 573 of file SDL_audio.c.

References SDL_AudioDevice::buffer_queue_head, SDL_AudioDevice::buffer_queue_tail, free_audio_queue(), get_audio_device(), SDL_AudioDriver::impl, SDL_AudioDriverImpl::LockDevice, NULL, SDL_AudioDevice::queued_bytes, SDLCALL, and SDL_AudioDriverImpl::UnlockDevice.

574 {
575  SDL_AudioDevice *device = get_audio_device(devid);
577  if (!device) {
578  return; /* nothing to do. */
579  }
580 
581  /* Blank out the device and release the mutex. Free it afterwards. */
582  current_audio.impl.LockDevice(device);
583  buffer = device->buffer_queue_head;
584  device->buffer_queue_tail = NULL;
585  device->buffer_queue_head = NULL;
586  device->queued_bytes = 0;
588 
589  free_audio_queue(buffer);
590 }
static SDL_AudioDriver current_audio
Definition: SDL_audio.c:33
void(* UnlockDevice)(_THIS)
Definition: SDL_sysaudio.h:81
SDL_AudioBufferQueue * buffer_queue_head
Definition: SDL_sysaudio.h:178
SDL_AudioBufferQueue * buffer_queue_tail
Definition: SDL_sysaudio.h:179
void(* LockDevice)(_THIS)
Definition: SDL_sysaudio.h:80
#define NULL
Definition: begin_code.h:143
static void free_audio_queue(SDL_AudioBufferQueue *buffer)
Definition: SDL_audio.c:423
SDL_AudioDriverImpl impl
Definition: SDL_sysaudio.h:120
GLuint buffer
static SDL_AudioDevice * get_audio_device(SDL_AudioDeviceID id)
Definition: SDL_audio.c:150
void SDL_CloseAudio ( void  )

This function shuts down audio processing and closes the audio device.

Definition at line 1339 of file SDL_audio.c.

References SDL_CloseAudioDevice().

1340 {
1342 }
void SDL_CloseAudioDevice(SDL_AudioDeviceID devid)
Definition: SDL_audio.c:1329
void SDL_CloseAudioDevice ( SDL_AudioDeviceID  dev)

Definition at line 1329 of file SDL_audio.c.

References close_audio_device(), get_audio_device(), and NULL.

Referenced by open_audio_device(), SDL_AudioQuit(), and SDL_CloseAudio().

1330 {
1331  SDL_AudioDevice *device = get_audio_device(devid);
1332  if (device) {
1333  close_audio_device(device);
1334  open_devices[devid - 1] = NULL;
1335  }
1336 }
static SDL_AudioDevice * open_devices[16]
Definition: SDL_audio.c:34
#define NULL
Definition: begin_code.h:143
static SDL_AudioDevice * get_audio_device(SDL_AudioDeviceID id)
Definition: SDL_audio.c:150
static void close_audio_device(SDL_AudioDevice *device)
Definition: SDL_audio.c:873
int SDL_ConvertAudio ( SDL_AudioCVT cvt)

Once you have initialized the cvt structure using SDL_BuildAudioCVT(), created an audio buffer cvt->buf, and filled it with cvt->len bytes of audio data in the source format, this function will convert it in-place to the desired format.

The data conversion may expand the size of the audio data, so the buffer cvt->buf should be allocated after the cvt structure is initialized by SDL_BuildAudioCVT(), and should be cvt->len*cvt->len_mult bytes long.

Definition at line 814 of file SDL_audiocvt.c.

References SDL_AudioCVT::buf, SDL_AudioCVT::filter_index, SDL_AudioCVT::filters, SDL_AudioCVT::len, SDL_AudioCVT::len_cvt, NULL, SDL_SetError, and SDL_AudioCVT::src_format.

815 {
816  /* !!! FIXME: (cvt) should be const; stack-copy it here. */
817  /* !!! FIXME: (actually, we can't...len_cvt needs to be updated. Grr.) */
818 
819  /* Make sure there's data to convert */
820  if (cvt->buf == NULL) {
821  SDL_SetError("No buffer allocated for conversion");
822  return (-1);
823  }
824  /* Return okay if no conversion is necessary */
825  cvt->len_cvt = cvt->len;
826  if (cvt->filters[0] == NULL) {
827  return (0);
828  }
829 
830  /* Set up the conversion and go! */
831  cvt->filter_index = 0;
832  cvt->filters[0] (cvt, cvt->src_format);
833  return (0);
834 }
Uint8 * buf
Definition: SDL_audio.h:206
int filter_index
Definition: SDL_audio.h:212
SDL_AudioFilter filters[10]
Definition: SDL_audio.h:211
SDL_AudioFormat src_format
Definition: SDL_audio.h:203
#define NULL
Definition: begin_code.h:143
#define SDL_SetError
void SDL_FreeWAV ( Uint8 audio_buf)

This function frees data previously allocated with SDL_LoadWAV_RW()

Definition at line 602 of file SDL_wave.c.

References SDL_free().

603 {
604  SDL_free(audio_buf);
605 }
void SDL_free(void *mem)
const char* SDL_GetAudioDeviceName ( int  index,
int  iscapture 
)

Get the human-readable name of a specific audio device. Must be a value between 0 and (number of audio devices-1). Only valid after a successfully initializing the audio subsystem. The values returned by this function reflect the latest call to SDL_GetNumAudioDevices(); recall that function to redetect available hardware.

The string returned by this function is UTF-8 encoded, read-only, and managed internally. You are not to free it. If you need to keep the string for any length of time, you should make your own copy of it, as it will be invalid next time any of several other SDL functions is called.

Definition at line 833 of file SDL_audio.c.

References SDL_AudioDriver::detectionLock, SDL_AudioDriverImpl::HasCaptureSupport, i, SDL_AudioDriver::impl, SDL_AudioDriver::inputDeviceCount, SDL_AudioDriver::inputDevices, SDL_AudioDeviceItem::next, NULL, SDL_AudioDriver::outputDeviceCount, SDL_AudioDriver::outputDevices, retval, SDL_assert, SDL_INIT_AUDIO, SDL_LockMutex, SDL_SetError, SDL_UnlockMutex, and SDL_WasInit.

834 {
835  const char *retval = NULL;
836 
837  if (!SDL_WasInit(SDL_INIT_AUDIO)) {
838  SDL_SetError("Audio subsystem is not initialized");
839  return NULL;
840  }
841 
842  if ((iscapture) && (!current_audio.impl.HasCaptureSupport)) {
843  SDL_SetError("No capture support");
844  return NULL;
845  }
846 
847  if (index >= 0) {
848  SDL_AudioDeviceItem *item;
849  int i;
850 
854  if (index < i) {
855  for (i--; i > index; i--, item = item->next) {
856  SDL_assert(item != NULL);
857  }
858  SDL_assert(item != NULL);
859  retval = item->name;
860  }
862  }
863 
864  if (retval == NULL) {
865  SDL_SetError("No such device");
866  }
867 
868  return retval;
869 }
#define SDL_LockMutex
struct SDL_AudioDeviceItem * next
Definition: SDL_sysaudio.h:101
static SDL_AudioDriver current_audio
Definition: SDL_audio.c:33
SDL_mutex * detectionLock
Definition: SDL_sysaudio.h:123
SDL_bool retval
GLuint index
SDL_AudioDeviceItem * outputDevices
Definition: SDL_sysaudio.h:128
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display Drawable _Xconst char unsigned int unsigned int return Display Pixmap Pixmap XColor XColor unsigned int unsigned int return Display _Xconst char char int char return Display Visual unsigned int int int char unsigned int unsigned int in i)
Definition: SDL_x11sym.h:42
#define SDL_assert(condition)
Definition: SDL_assert.h:167
#define NULL
Definition: begin_code.h:143
#define SDL_SetError
#define SDL_INIT_AUDIO
Definition: SDL.h:76
SDL_AudioDriverImpl impl
Definition: SDL_sysaudio.h:120
#define SDL_UnlockMutex
#define SDL_WasInit
SDL_AudioDeviceItem * inputDevices
Definition: SDL_sysaudio.h:129
SDL_AudioStatus SDL_GetAudioDeviceStatus ( SDL_AudioDeviceID  dev)

Definition at line 1257 of file SDL_audio.c.

References SDL_AudioDevice::enabled, get_audio_device(), SDL_AudioDevice::paused, SDL_AUDIO_PAUSED, SDL_AUDIO_PLAYING, and SDL_AUDIO_STOPPED.

Referenced by SDL_GetAudioStatus().

1258 {
1259  SDL_AudioDevice *device = get_audio_device(devid);
1261  if (device && device->enabled) {
1262  if (device->paused) {
1263  status = SDL_AUDIO_PAUSED;
1264  } else {
1265  status = SDL_AUDIO_PLAYING;
1266  }
1267  }
1268  return status;
1269 }
SDL_AudioStatus
Definition: SDL_audio.h:368
static SDL_AudioDevice * get_audio_device(SDL_AudioDeviceID id)
Definition: SDL_audio.c:150
const char* SDL_GetAudioDriver ( int  index)

Definition at line 702 of file SDL_audio.c.

References AudioBootStrap::name, NULL, and SDL_GetNumAudioDrivers().

703 {
704  if (index >= 0 && index < SDL_GetNumAudioDrivers()) {
705  return bootstrap[index]->name;
706  }
707  return NULL;
708 }
int SDL_GetNumAudioDrivers(void)
Definition: SDL_audio.c:696
const char * name
Definition: SDL_sysaudio.h:191
GLuint index
static const AudioBootStrap *const bootstrap[]
Definition: SDL_audio.c:76
#define NULL
Definition: begin_code.h:143
SDL_AudioStatus SDL_GetAudioStatus ( void  )

Definition at line 1273 of file SDL_audio.c.

References SDL_GetAudioDeviceStatus().

1274 {
1275  return SDL_GetAudioDeviceStatus(1);
1276 }
SDL_AudioStatus SDL_GetAudioDeviceStatus(SDL_AudioDeviceID devid)
Definition: SDL_audio.c:1257
const char* SDL_GetCurrentAudioDriver ( void  )

This function returns the name of the current audio driver, or NULL if no driver has been initialized.

Definition at line 772 of file SDL_audio.c.

References SDL_AudioDriver::name.

773 {
774  return current_audio.name;
775 }
const char * name
Definition: SDL_sysaudio.h:114
static SDL_AudioDriver current_audio
Definition: SDL_audio.c:33
int SDL_GetNumAudioDevices ( int  iscapture)

Get the number of available devices exposed by the current driver. Only valid after a successfully initializing the audio subsystem. Returns -1 if an explicit list of devices can't be determined; this is not an error. For example, if SDL is set up to talk to a remote audio server, it can't list every one available on the Internet, but it will still allow a specific host to be specified to SDL_OpenAudioDevice().

In many common cases, when this function returns a value <= 0, it can still successfully open the default device (NULL for first argument of SDL_OpenAudioDevice()).

Definition at line 807 of file SDL_audio.c.

References SDL_AudioDriver::captureDevicesRemoved, clean_out_device_list(), SDL_AudioDriver::detectionLock, SDL_AudioDriver::inputDeviceCount, SDL_AudioDriver::inputDevices, SDL_AudioDriver::outputDeviceCount, SDL_AudioDriver::outputDevices, SDL_AudioDriver::outputDevicesRemoved, retval, SDL_FALSE, SDL_INIT_AUDIO, SDL_LockMutex, SDL_UnlockMutex, and SDL_WasInit.

808 {
809  int retval = 0;
810 
811  if (!SDL_WasInit(SDL_INIT_AUDIO)) {
812  return -1;
813  }
814 
816  if (iscapture && current_audio.captureDevicesRemoved) {
818  }
819 
820  if (!iscapture && current_audio.outputDevicesRemoved) {
823  }
824 
827 
828  return retval;
829 }
#define SDL_LockMutex
SDL_bool captureDevicesRemoved
Definition: SDL_sysaudio.h:124
static void clean_out_device_list(SDL_AudioDeviceItem **devices, int *devCount, SDL_bool *removedFlag)
Definition: SDL_audio.c:779
static SDL_AudioDriver current_audio
Definition: SDL_audio.c:33
SDL_mutex * detectionLock
Definition: SDL_sysaudio.h:123
SDL_bool retval
SDL_AudioDeviceItem * outputDevices
Definition: SDL_sysaudio.h:128
SDL_bool outputDevicesRemoved
Definition: SDL_sysaudio.h:125
#define SDL_INIT_AUDIO
Definition: SDL.h:76
#define SDL_UnlockMutex
#define SDL_WasInit
SDL_AudioDeviceItem * inputDevices
Definition: SDL_sysaudio.h:129
int SDL_GetNumAudioDrivers ( void  )

Definition at line 696 of file SDL_audio.c.

References SDL_arraysize.

Referenced by SDL_GetAudioDriver().

697 {
698  return SDL_arraysize(bootstrap) - 1;
699 }
static const AudioBootStrap *const bootstrap[]
Definition: SDL_audio.c:76
#define SDL_arraysize(array)
Definition: SDL_stdinc.h:93
Uint32 SDL_GetQueuedAudioSize ( SDL_AudioDeviceID  dev)

Get the number of bytes of still-queued audio.

This is the number of bytes that have been queued for playback with SDL_QueueAudio(), but have not yet been sent to the hardware.

Once we've sent it to the hardware, this function can not decide the exact byte boundary of what has been played. It's possible that we just gave the hardware several kilobytes right before you called this function, but it hasn't played any of it yet, or maybe half of it, etc.

You may not queue audio on a device that is using an application-supplied callback; calling this function on such a device always returns 0. You have to use the audio callback or queue audio with SDL_QueueAudio(), but not both.

You should not call SDL_LockAudio() on the device before querying; SDL handles locking internally for this function.

Parameters
devThe device ID of which we will query queued audio size.
Returns
Number of bytes (not samples!) of queued audio.
See also
SDL_QueueAudio
SDL_ClearQueuedAudio

Definition at line 557 of file SDL_audio.c.

References SDL_AudioSpec::callback, get_audio_device(), SDL_AudioDriverImpl::GetPendingBytes, SDL_AudioDriver::impl, SDL_AudioDriverImpl::LockDevice, SDL_AudioDevice::queued_bytes, retval, SDL_BufferQueueDrainCallback(), SDL_AudioDevice::spec, and SDL_AudioDriverImpl::UnlockDevice.

558 {
559  Uint32 retval = 0;
560  SDL_AudioDevice *device = get_audio_device(devid);
561 
562  /* Nothing to do unless we're set up for queueing. */
563  if (device && (device->spec.callback == SDL_BufferQueueDrainCallback)) {
564  current_audio.impl.LockDevice(device);
565  retval = device->queued_bytes + current_audio.impl.GetPendingBytes(device);
567  }
568 
569  return retval;
570 }
uint32_t Uint32
An unsigned 32-bit integer type.
Definition: SDL_stdinc.h:155
SDL_AudioSpec spec
Definition: SDL_sysaudio.h:150
static SDL_AudioDriver current_audio
Definition: SDL_audio.c:33
void(* UnlockDevice)(_THIS)
Definition: SDL_sysaudio.h:81
SDL_bool retval
SDL_AudioCallback callback
Definition: SDL_audio.h:177
void(* LockDevice)(_THIS)
Definition: SDL_sysaudio.h:80
SDL_AudioDriverImpl impl
Definition: SDL_sysaudio.h:120
int(* GetPendingBytes)(_THIS)
Definition: SDL_sysaudio.h:76
static void SDL_BufferQueueDrainCallback(void *userdata, Uint8 *stream, int _len)
Definition: SDL_audio.c:433
static SDL_AudioDevice * get_audio_device(SDL_AudioDeviceID id)
Definition: SDL_audio.c:150
SDL_AudioSpec* SDL_LoadWAV_RW ( SDL_RWops src,
int  freesrc,
SDL_AudioSpec spec,
Uint8 **  audio_buf,
Uint32 audio_len 
)

This function loads a WAVE from the data source, automatically freeing that source if freesrc is non-zero. For example, to load a WAVE file, you could do:

1 SDL_LoadWAV_RW(SDL_RWFromFile("sample.wav", "rb"), 1, ...);

If this function succeeds, it returns the given SDL_AudioSpec, filled with the audio data format of the wave data, and sets *audio_buf to a malloc()'d buffer containing the audio data, and sets *audio_len to the length of that audio buffer, in bytes. You need to free the audio buffer with SDL_FreeWAV() when you are done with it.

This function returns NULL and sets the SDL error message if the wave file cannot be opened, uses an unknown data format, or is corrupt. Currently raw and MS-ADPCM WAVE files are supported.

Definition at line 407 of file SDL_wave.c.

References AUDIO_F32, AUDIO_S16, AUDIO_S32, AUDIO_U8, BEXT, WaveFMT::bitspersample, WaveFMT::channels, SDL_AudioSpec::channels, DATA, Chunk::data, done, WaveFMT::encoding, FACT, FMT, SDL_AudioSpec::format, SDL_AudioSpec::freq, WaveFMT::frequency, IEEE_FLOAT_CODE, IMA_ADPCM_CODE, IMA_ADPCM_decode(), InitIMA_ADPCM(), InitMS_ADPCM(), JUNK, Chunk::length, LIST, Chunk::magic, MP3_CODE, MS_ADPCM_CODE, MS_ADPCM_decode(), NULL, PCM_CODE, ReadChunk(), RIFF, RW_SEEK_CUR, SDL_AudioSpec::samples, SDL_AUDIO_BITSIZE, SDL_free(), SDL_memset, SDL_ReadLE32, SDL_RWclose, SDL_RWseek, SDL_SetError, SDL_SwapLE16, SDL_SwapLE32, SDL_zero, and WAVE.

409 {
410  int was_error;
411  Chunk chunk;
412  int lenread;
413  int IEEE_float_encoded, MS_ADPCM_encoded, IMA_ADPCM_encoded;
414  int samplesize;
415 
416  /* WAV magic header */
417  Uint32 RIFFchunk;
418  Uint32 wavelen = 0;
419  Uint32 WAVEmagic;
420  Uint32 headerDiff = 0;
421 
422  /* FMT chunk */
423  WaveFMT *format = NULL;
424 
425  SDL_zero(chunk);
426 
427  /* Make sure we are passed a valid data source */
428  was_error = 0;
429  if (src == NULL) {
430  was_error = 1;
431  goto done;
432  }
433 
434  /* Check the magic header */
435  RIFFchunk = SDL_ReadLE32(src);
436  wavelen = SDL_ReadLE32(src);
437  if (wavelen == WAVE) { /* The RIFFchunk has already been read */
438  WAVEmagic = wavelen;
439  wavelen = RIFFchunk;
440  RIFFchunk = RIFF;
441  } else {
442  WAVEmagic = SDL_ReadLE32(src);
443  }
444  if ((RIFFchunk != RIFF) || (WAVEmagic != WAVE)) {
445  SDL_SetError("Unrecognized file type (not WAVE)");
446  was_error = 1;
447  goto done;
448  }
449  headerDiff += sizeof(Uint32); /* for WAVE */
450 
451  /* Read the audio data format chunk */
452  chunk.data = NULL;
453  do {
454  SDL_free(chunk.data);
455  chunk.data = NULL;
456  lenread = ReadChunk(src, &chunk);
457  if (lenread < 0) {
458  was_error = 1;
459  goto done;
460  }
461  /* 2 Uint32's for chunk header+len, plus the lenread */
462  headerDiff += lenread + 2 * sizeof(Uint32);
463  } while ((chunk.magic == FACT) || (chunk.magic == LIST) || (chunk.magic == BEXT) || (chunk.magic == JUNK));
464 
465  /* Decode the audio data format */
466  format = (WaveFMT *) chunk.data;
467  if (chunk.magic != FMT) {
468  SDL_SetError("Complex WAVE files not supported");
469  was_error = 1;
470  goto done;
471  }
472  IEEE_float_encoded = MS_ADPCM_encoded = IMA_ADPCM_encoded = 0;
473  switch (SDL_SwapLE16(format->encoding)) {
474  case PCM_CODE:
475  /* We can understand this */
476  break;
477  case IEEE_FLOAT_CODE:
478  IEEE_float_encoded = 1;
479  /* We can understand this */
480  break;
481  case MS_ADPCM_CODE:
482  /* Try to understand this */
483  if (InitMS_ADPCM(format) < 0) {
484  was_error = 1;
485  goto done;
486  }
487  MS_ADPCM_encoded = 1;
488  break;
489  case IMA_ADPCM_CODE:
490  /* Try to understand this */
491  if (InitIMA_ADPCM(format) < 0) {
492  was_error = 1;
493  goto done;
494  }
495  IMA_ADPCM_encoded = 1;
496  break;
497  case MP3_CODE:
498  SDL_SetError("MPEG Layer 3 data not supported");
499  was_error = 1;
500  goto done;
501  default:
502  SDL_SetError("Unknown WAVE data format: 0x%.4x",
503  SDL_SwapLE16(format->encoding));
504  was_error = 1;
505  goto done;
506  }
507  SDL_memset(spec, 0, (sizeof *spec));
508  spec->freq = SDL_SwapLE32(format->frequency);
509 
510  if (IEEE_float_encoded) {
511  if ((SDL_SwapLE16(format->bitspersample)) != 32) {
512  was_error = 1;
513  } else {
514  spec->format = AUDIO_F32;
515  }
516  } else {
517  switch (SDL_SwapLE16(format->bitspersample)) {
518  case 4:
519  if (MS_ADPCM_encoded || IMA_ADPCM_encoded) {
520  spec->format = AUDIO_S16;
521  } else {
522  was_error = 1;
523  }
524  break;
525  case 8:
526  spec->format = AUDIO_U8;
527  break;
528  case 16:
529  spec->format = AUDIO_S16;
530  break;
531  case 32:
532  spec->format = AUDIO_S32;
533  break;
534  default:
535  was_error = 1;
536  break;
537  }
538  }
539 
540  if (was_error) {
541  SDL_SetError("Unknown %d-bit PCM data format",
542  SDL_SwapLE16(format->bitspersample));
543  goto done;
544  }
545  spec->channels = (Uint8) SDL_SwapLE16(format->channels);
546  spec->samples = 4096; /* Good default buffer size */
547 
548  /* Read the audio data chunk */
549  *audio_buf = NULL;
550  do {
551  SDL_free(*audio_buf);
552  *audio_buf = NULL;
553  lenread = ReadChunk(src, &chunk);
554  if (lenread < 0) {
555  was_error = 1;
556  goto done;
557  }
558  *audio_len = lenread;
559  *audio_buf = chunk.data;
560  if (chunk.magic != DATA)
561  headerDiff += lenread + 2 * sizeof(Uint32);
562  } while (chunk.magic != DATA);
563  headerDiff += 2 * sizeof(Uint32); /* for the data chunk and len */
564 
565  if (MS_ADPCM_encoded) {
566  if (MS_ADPCM_decode(audio_buf, audio_len) < 0) {
567  was_error = 1;
568  goto done;
569  }
570  }
571  if (IMA_ADPCM_encoded) {
572  if (IMA_ADPCM_decode(audio_buf, audio_len) < 0) {
573  was_error = 1;
574  goto done;
575  }
576  }
577 
578  /* Don't return a buffer that isn't a multiple of samplesize */
579  samplesize = ((SDL_AUDIO_BITSIZE(spec->format)) / 8) * spec->channels;
580  *audio_len &= ~(samplesize - 1);
581 
582  done:
583  SDL_free(format);
584  if (src) {
585  if (freesrc) {
586  SDL_RWclose(src);
587  } else {
588  /* seek to the end of the file (given by the RIFF chunk) */
589  SDL_RWseek(src, wavelen - chunk.length - headerDiff, RW_SEEK_CUR);
590  }
591  }
592  if (was_error) {
593  spec = NULL;
594  }
595  return (spec);
596 }
static int InitIMA_ADPCM(WaveFMT *format)
Definition: SDL_wave.c:232
GLint GLint GLsizei GLsizei GLsizei GLint GLenum format
Definition: SDL_opengl.h:1565
#define PCM_CODE
Definition: SDL_wave.h:36
#define RIFF
Definition: SDL_wave.h:28
#define LIST
Definition: SDL_wave.h:31
uint32_t Uint32
An unsigned 32-bit integer type.
Definition: SDL_stdinc.h:155
#define MP3_CODE
Definition: SDL_wave.h:40
Definition: SDL_wave.h:60
#define SDL_ReadLE32
Uint32 length
Definition: SDL_wave.h:63
Uint16 samples
Definition: SDL_audio.h:174
Uint16 encoding
Definition: SDL_wave.h:51
static int MS_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
Definition: SDL_wave.c:119
Uint16 channels
Definition: SDL_wave.h:52
#define FMT
Definition: SDL_wave.h:34
#define SDL_RWseek(ctx, offset, whence)
Definition: SDL_rwops.h:185
#define AUDIO_U8
Definition: SDL_audio.h:89
#define DATA
Definition: SDL_wave.h:35
#define FACT
Definition: SDL_wave.h:30
Uint8 channels
Definition: SDL_audio.h:172
static int IMA_ADPCM_decode(Uint8 **audio_buf, Uint32 *audio_len)
Definition: SDL_wave.c:338
uint8_t Uint8
An unsigned 8-bit integer type.
Definition: SDL_stdinc.h:139
void SDL_free(void *mem)
#define SDL_AUDIO_BITSIZE(x)
Definition: SDL_audio.h:75
#define SDL_SwapLE32(X)
Definition: SDL_endian.h:212
int done
Definition: checkkeys.c:28
#define AUDIO_S32
Definition: SDL_audio.h:105
#define WAVE
Definition: SDL_wave.h:29
#define JUNK
Definition: SDL_wave.h:33
#define SDL_zero(x)
Definition: SDL_stdinc.h:355
Uint8 * data
Definition: SDL_wave.h:64
#define NULL
Definition: begin_code.h:143
#define IEEE_FLOAT_CODE
Definition: SDL_wave.h:38
#define SDL_RWclose(ctx)
Definition: SDL_rwops.h:189
#define IMA_ADPCM_CODE
Definition: SDL_wave.h:39
#define SDL_SetError
SDL_AudioFormat format
Definition: SDL_audio.h:171
static int InitMS_ADPCM(WaveFMT *format)
Definition: SDL_wave.c:49
Uint32 magic
Definition: SDL_wave.h:62
#define AUDIO_S16
Definition: SDL_audio.h:96
Uint32 frequency
Definition: SDL_wave.h:53
#define RW_SEEK_CUR
Definition: SDL_rwops.h:175
Uint16 bitspersample
Definition: SDL_wave.h:56
#define AUDIO_F32
Definition: SDL_audio.h:114
#define SDL_SwapLE16(X)
Definition: SDL_endian.h:211
#define BEXT
Definition: SDL_wave.h:32
#define SDL_memset
static int ReadChunk(SDL_RWops *src, Chunk *chunk)
Definition: SDL_wave.c:608
#define MS_ADPCM_CODE
Definition: SDL_wave.h:37
void SDL_LockAudio ( void  )

Definition at line 1307 of file SDL_audio.c.

References SDL_LockAudioDevice().

1308 {
1310 }
void SDL_LockAudioDevice(SDL_AudioDeviceID devid)
Definition: SDL_audio.c:1297
void SDL_LockAudioDevice ( SDL_AudioDeviceID  dev)

Definition at line 1297 of file SDL_audio.c.

References get_audio_device(), SDL_AudioDriver::impl, and SDL_AudioDriverImpl::LockDevice.

Referenced by SDL_LockAudio().

1298 {
1299  /* Obtain a lock on the mixing buffers */
1300  SDL_AudioDevice *device = get_audio_device(devid);
1301  if (device) {
1302  current_audio.impl.LockDevice(device);
1303  }
1304 }
static SDL_AudioDriver current_audio
Definition: SDL_audio.c:33
void(* LockDevice)(_THIS)
Definition: SDL_sysaudio.h:80
SDL_AudioDriverImpl impl
Definition: SDL_sysaudio.h:120
static SDL_AudioDevice * get_audio_device(SDL_AudioDeviceID id)
Definition: SDL_audio.c:150
void SDL_MixAudio ( Uint8 dst,
const Uint8 src,
Uint32  len,
int  volume 
)

This takes two audio buffers of the playing audio format and mixes them, performing addition, volume adjustment, and overflow clipping. The volume ranges from 0 - 128, and should be set to SDL_MIX_MAXVOLUME for full audio volume. Note this does not change hardware volume. This is provided for convenience – you can mix your own audio data.

Definition at line 1440 of file SDL_audio.c.

References SDL_AudioDevice::convert, SDL_AudioSpec::format, get_audio_device(), SDL_AudioCVT::needed, NULL, SDL_MixAudioFormat, SDL_AudioDevice::spec, and SDL_AudioCVT::src_format.

1441 {
1442  /* Mix the user-level audio format */
1443  SDL_AudioDevice *device = get_audio_device(1);
1444  if (device != NULL) {
1446  if (device->convert.needed) {
1447  format = device->convert.src_format;
1448  } else {
1449  format = device->spec.format;
1450  }
1451  SDL_MixAudioFormat(dst, src, format, len, volume);
1452  }
1453 }
GLenum GLenum dst
GLint GLint GLsizei GLsizei GLsizei GLint GLenum format
Definition: SDL_opengl.h:1565
#define SDL_MixAudioFormat
SDL_AudioSpec spec
Definition: SDL_sysaudio.h:150
Uint16 SDL_AudioFormat
Audio format flags.
Definition: SDL_audio.h:64
GLenum GLsizei len
SDL_AudioFormat src_format
Definition: SDL_audio.h:203
#define NULL
Definition: begin_code.h:143
SDL_AudioFormat format
Definition: SDL_audio.h:171
SDL_AudioCVT convert
Definition: SDL_sysaudio.h:153
GLenum src
static SDL_AudioDevice * get_audio_device(SDL_AudioDeviceID id)
Definition: SDL_audio.c:150
void SDL_MixAudioFormat ( Uint8 dst,
const Uint8 src,
SDL_AudioFormat  format,
Uint32  len,
int  volume 
)

This works like SDL_MixAudio(), but you specify the audio format instead of using the format of audio device 1. Thus it can be used when no audio device is open at all.

Definition at line 90 of file SDL_mixer.c.

References ADJUST_VOLUME, ADJUST_VOLUME_U8, AUDIO_F32LSB, AUDIO_F32MSB, AUDIO_S16LSB, AUDIO_S16MSB, AUDIO_S32LSB, AUDIO_S32MSB, AUDIO_S8, AUDIO_U8, F, mix8, SDL_MIX_MAXVOLUME, SDL_SetError, SDL_SwapBE32, SDL_SwapFloatBE, SDL_SwapFloatLE, and SDL_SwapLE32.

92 {
93  if (volume == 0) {
94  return;
95  }
96 
97  switch (format) {
98 
99  case AUDIO_U8:
100  {
101 #if defined(__GNUC__) && defined(__M68000__) && !defined(__mcoldfire__) && defined(SDL_ASSEMBLY_ROUTINES)
102  SDL_MixAudio_m68k_U8((char *) dst, (char *) src,
103  (unsigned long) len, (long) volume,
104  (char *) mix8);
105 #else
106  Uint8 src_sample;
107 
108  while (len--) {
109  src_sample = *src;
110  ADJUST_VOLUME_U8(src_sample, volume);
111  *dst = mix8[*dst + src_sample];
112  ++dst;
113  ++src;
114  }
115 #endif
116  }
117  break;
118 
119  case AUDIO_S8:
120  {
121  Sint8 *dst8, *src8;
122  Sint8 src_sample;
123  int dst_sample;
124  const int max_audioval = ((1 << (8 - 1)) - 1);
125  const int min_audioval = -(1 << (8 - 1));
126 
127  src8 = (Sint8 *) src;
128  dst8 = (Sint8 *) dst;
129  while (len--) {
130  src_sample = *src8;
131  ADJUST_VOLUME(src_sample, volume);
132  dst_sample = *dst8 + src_sample;
133  if (dst_sample > max_audioval) {
134  *dst8 = max_audioval;
135  } else if (dst_sample < min_audioval) {
136  *dst8 = min_audioval;
137  } else {
138  *dst8 = dst_sample;
139  }
140  ++dst8;
141  ++src8;
142  }
143  }
144  break;
145 
146  case AUDIO_S16LSB:
147  {
148  Sint16 src1, src2;
149  int dst_sample;
150  const int max_audioval = ((1 << (16 - 1)) - 1);
151  const int min_audioval = -(1 << (16 - 1));
152 
153  len /= 2;
154  while (len--) {
155  src1 = ((src[1]) << 8 | src[0]);
156  ADJUST_VOLUME(src1, volume);
157  src2 = ((dst[1]) << 8 | dst[0]);
158  src += 2;
159  dst_sample = src1 + src2;
160  if (dst_sample > max_audioval) {
161  dst_sample = max_audioval;
162  } else if (dst_sample < min_audioval) {
163  dst_sample = min_audioval;
164  }
165  dst[0] = dst_sample & 0xFF;
166  dst_sample >>= 8;
167  dst[1] = dst_sample & 0xFF;
168  dst += 2;
169  }
170  }
171  break;
172 
173  case AUDIO_S16MSB:
174  {
175 #if defined(__GNUC__) && defined(__M68000__) && !defined(__mcoldfire__) && defined(SDL_ASSEMBLY_ROUTINES)
176  SDL_MixAudio_m68k_S16MSB((short *) dst, (short *) src,
177  (unsigned long) len, (long) volume);
178 #else
179  Sint16 src1, src2;
180  int dst_sample;
181  const int max_audioval = ((1 << (16 - 1)) - 1);
182  const int min_audioval = -(1 << (16 - 1));
183 
184  len /= 2;
185  while (len--) {
186  src1 = ((src[0]) << 8 | src[1]);
187  ADJUST_VOLUME(src1, volume);
188  src2 = ((dst[0]) << 8 | dst[1]);
189  src += 2;
190  dst_sample = src1 + src2;
191  if (dst_sample > max_audioval) {
192  dst_sample = max_audioval;
193  } else if (dst_sample < min_audioval) {
194  dst_sample = min_audioval;
195  }
196  dst[1] = dst_sample & 0xFF;
197  dst_sample >>= 8;
198  dst[0] = dst_sample & 0xFF;
199  dst += 2;
200  }
201 #endif
202  }
203  break;
204 
205  case AUDIO_S32LSB:
206  {
207  const Uint32 *src32 = (Uint32 *) src;
208  Uint32 *dst32 = (Uint32 *) dst;
209  Sint64 src1, src2;
210  Sint64 dst_sample;
211  const Sint64 max_audioval = ((((Sint64) 1) << (32 - 1)) - 1);
212  const Sint64 min_audioval = -(((Sint64) 1) << (32 - 1));
213 
214  len /= 4;
215  while (len--) {
216  src1 = (Sint64) ((Sint32) SDL_SwapLE32(*src32));
217  src32++;
218  ADJUST_VOLUME(src1, volume);
219  src2 = (Sint64) ((Sint32) SDL_SwapLE32(*dst32));
220  dst_sample = src1 + src2;
221  if (dst_sample > max_audioval) {
222  dst_sample = max_audioval;
223  } else if (dst_sample < min_audioval) {
224  dst_sample = min_audioval;
225  }
226  *(dst32++) = SDL_SwapLE32((Uint32) ((Sint32) dst_sample));
227  }
228  }
229  break;
230 
231  case AUDIO_S32MSB:
232  {
233  const Uint32 *src32 = (Uint32 *) src;
234  Uint32 *dst32 = (Uint32 *) dst;
235  Sint64 src1, src2;
236  Sint64 dst_sample;
237  const Sint64 max_audioval = ((((Sint64) 1) << (32 - 1)) - 1);
238  const Sint64 min_audioval = -(((Sint64) 1) << (32 - 1));
239 
240  len /= 4;
241  while (len--) {
242  src1 = (Sint64) ((Sint32) SDL_SwapBE32(*src32));
243  src32++;
244  ADJUST_VOLUME(src1, volume);
245  src2 = (Sint64) ((Sint32) SDL_SwapBE32(*dst32));
246  dst_sample = src1 + src2;
247  if (dst_sample > max_audioval) {
248  dst_sample = max_audioval;
249  } else if (dst_sample < min_audioval) {
250  dst_sample = min_audioval;
251  }
252  *(dst32++) = SDL_SwapBE32((Uint32) ((Sint32) dst_sample));
253  }
254  }
255  break;
256 
257  case AUDIO_F32LSB:
258  {
259  const float fmaxvolume = 1.0f / ((float) SDL_MIX_MAXVOLUME);
260  const float fvolume = (float) volume;
261  const float *src32 = (float *) src;
262  float *dst32 = (float *) dst;
263  float src1, src2;
264  double dst_sample;
265  /* !!! FIXME: are these right? */
266  const double max_audioval = 3.402823466e+38F;
267  const double min_audioval = -3.402823466e+38F;
268 
269  len /= 4;
270  while (len--) {
271  src1 = ((SDL_SwapFloatLE(*src32) * fvolume) * fmaxvolume);
272  src2 = SDL_SwapFloatLE(*dst32);
273  src32++;
274 
275  dst_sample = ((double) src1) + ((double) src2);
276  if (dst_sample > max_audioval) {
277  dst_sample = max_audioval;
278  } else if (dst_sample < min_audioval) {
279  dst_sample = min_audioval;
280  }
281  *(dst32++) = SDL_SwapFloatLE((float) dst_sample);
282  }
283  }
284  break;
285 
286  case AUDIO_F32MSB:
287  {
288  const float fmaxvolume = 1.0f / ((float) SDL_MIX_MAXVOLUME);
289  const float fvolume = (float) volume;
290  const float *src32 = (float *) src;
291  float *dst32 = (float *) dst;
292  float src1, src2;
293  double dst_sample;
294  /* !!! FIXME: are these right? */
295  const double max_audioval = 3.402823466e+38F;
296  const double min_audioval = -3.402823466e+38F;
297 
298  len /= 4;
299  while (len--) {
300  src1 = ((SDL_SwapFloatBE(*src32) * fvolume) * fmaxvolume);
301  src2 = SDL_SwapFloatBE(*dst32);
302  src32++;
303 
304  dst_sample = ((double) src1) + ((double) src2);
305  if (dst_sample > max_audioval) {
306  dst_sample = max_audioval;
307  } else if (dst_sample < min_audioval) {
308  dst_sample = min_audioval;
309  }
310  *(dst32++) = SDL_SwapFloatBE((float) dst_sample);
311  }
312  }
313  break;
314 
315  default: /* If this happens... FIXME! */
316  SDL_SetError("SDL_MixAudio(): unknown audio format");
317  return;
318  }
319 }
#define SDL_MIX_MAXVOLUME
Definition: SDL_audio.h:461
GLenum GLenum dst
#define ADJUST_VOLUME(s, v)
Definition: SDL_mixer.c:85
GLint GLint GLsizei GLsizei GLsizei GLint GLenum format
Definition: SDL_opengl.h:1565
#define SDL_SwapFloatBE(X)
Definition: SDL_endian.h:218
#define AUDIO_S32MSB
Definition: SDL_audio.h:104
uint32_t Uint32
An unsigned 32-bit integer type.
Definition: SDL_stdinc.h:155
#define SDL_SwapFloatLE(X)
Definition: SDL_endian.h:214
GLenum GLsizei len
#define SDL_SwapBE32(X)
Definition: SDL_endian.h:216
#define AUDIO_F32MSB
Definition: SDL_audio.h:113
static const Uint8 mix8[]
Definition: SDL_mixer.c:34
#define AUDIO_U8
Definition: SDL_audio.h:89
int8_t Sint8
A signed 8-bit integer type.
Definition: SDL_stdinc.h:135
uint8_t Uint8
An unsigned 8-bit integer type.
Definition: SDL_stdinc.h:139
#define ADJUST_VOLUME_U8(s, v)
Definition: SDL_mixer.c:86
#define SDL_SwapLE32(X)
Definition: SDL_endian.h:212
#define AUDIO_F32LSB
Definition: SDL_audio.h:112
#define AUDIO_S32LSB
Definition: SDL_audio.h:103
int32_t Sint32
A signed 32-bit integer type.
Definition: SDL_stdinc.h:151
#define SDL_SetError
#define AUDIO_S16MSB
Definition: SDL_audio.h:94
#define AUDIO_S16LSB
Definition: SDL_audio.h:92
#define F(x, y, z)
Definition: SDL_test_md5.c:73
int64_t Sint64
A signed 64-bit integer type.
Definition: SDL_stdinc.h:160
#define AUDIO_S8
Definition: SDL_audio.h:90
GLenum src
int16_t Sint16
A signed 16-bit integer type.
Definition: SDL_stdinc.h:143
int SDL_OpenAudio ( SDL_AudioSpec desired,
SDL_AudioSpec obtained 
)

This function opens the audio device with the desired parameters, and returns 0 if successful, placing the actual hardware parameters in the structure pointed to by obtained. If obtained is NULL, the audio data passed to the callback function will be guaranteed to be in the requested format, and will be automatically converted to the hardware audio format if necessary. This function returns -1 if it failed to open the audio device, or couldn't set up the audio thread.

When filling in the desired audio spec structure,

  • desired->freq should be the desired audio frequency in samples-per- second.
  • desired->format should be the desired audio format.
  • desired->samples is the desired size of the audio buffer, in samples. This number should be a power of two, and may be adjusted by the audio driver to a value more suitable for the hardware. Good values seem to range between 512 and 8096 inclusive, depending on the application and CPU speed. Smaller values yield faster response time, but can lead to underflow if the application is doing heavy processing and cannot fill the audio buffer in time. A stereo sample consists of both right and left channels in LR ordering. Note that the number of samples is directly related to time by the following formula:
    1 ms = (samples*1000)/freq
  • desired->size is the size in bytes of the audio buffer, and is calculated by SDL_OpenAudio().
  • desired->silence is the value used to set the buffer to silence, and is calculated by SDL_OpenAudio().
  • desired->callback should be set to a function that will be called when the audio device is ready for more data. It is passed a pointer to the audio buffer, and the length in bytes of the audio buffer. This function usually runs in a separate thread, and so you should protect data structures that it accesses by calling SDL_LockAudio() and SDL_UnlockAudio() in your code. Alternately, you may pass a NULL pointer here, and call SDL_QueueAudio() with some frequency, to queue more audio samples to be played.
  • desired->userdata is passed as the first parameter to your callback function. If you passed a NULL callback, this value is ignored.

The audio device starts out playing silence when it's opened, and should be enabled for playing by calling SDL_PauseAudio(0) when you are ready for your audio callback function to be called. Since the audio driver may modify the requested size of the audio buffer, you should allocate any local mixing buffers after you open the audio device.

Definition at line 1219 of file SDL_audio.c.

References NULL, open_audio_device(), SDL_assert, SDL_AUDIO_ALLOW_ANY_CHANGE, SDL_INIT_AUDIO, SDL_InitSubSystem, SDL_SetError, and SDL_WasInit.

1220 {
1221  SDL_AudioDeviceID id = 0;
1222 
1223  /* Start up the audio driver, if necessary. This is legacy behaviour! */
1224  if (!SDL_WasInit(SDL_INIT_AUDIO)) {
1225  if (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0) {
1226  return -1;
1227  }
1228  }
1229 
1230  /* SDL_OpenAudio() is legacy and can only act on Device ID #1. */
1231  if (open_devices[0] != NULL) {
1232  SDL_SetError("Audio device is already opened");
1233  return -1;
1234  }
1235 
1236  if (obtained) {
1237  id = open_audio_device(NULL, 0, desired, obtained,
1239  } else {
1240  id = open_audio_device(NULL, 0, desired, NULL, 0, 1);
1241  }
1242 
1243  SDL_assert((id == 0) || (id == 1));
1244  return (id == 0) ? -1 : 0;
1245 }
static SDL_AudioDevice * open_devices[16]
Definition: SDL_audio.c:34
#define SDL_InitSubSystem
#define SDL_AUDIO_ALLOW_ANY_CHANGE
Definition: SDL_audio.h:143
#define SDL_assert(condition)
Definition: SDL_assert.h:167
#define NULL
Definition: begin_code.h:143
#define SDL_SetError
static SDL_AudioDeviceID open_audio_device(const char *devname, int iscapture, const SDL_AudioSpec *desired, SDL_AudioSpec *obtained, int allowed_changes, int min_id)
Definition: SDL_audio.c:962
#define SDL_INIT_AUDIO
Definition: SDL.h:76
Uint32 SDL_AudioDeviceID
Definition: SDL_audio.h:303
#define SDL_WasInit
SDL_AudioDeviceID SDL_OpenAudioDevice ( const char *  device,
int  iscapture,
const SDL_AudioSpec desired,
SDL_AudioSpec obtained,
int  allowed_changes 
)

Open a specific audio device. Passing in a device name of NULL requests the most reasonable default (and is equivalent to calling SDL_OpenAudio()).

The device name is a UTF-8 string reported by SDL_GetAudioDeviceName(), but some drivers allow arbitrary and driver-specific strings, such as a hostname/IP address for a remote audio server, or a filename in the diskaudio driver.

Returns
0 on error, a valid device ID that is >= 2 on success.

SDL_OpenAudio(), unlike this function, always acts on device ID 1.

Definition at line 1248 of file SDL_audio.c.

References open_audio_device().

1251 {
1252  return open_audio_device(device, iscapture, desired, obtained,
1253  allowed_changes, 2);
1254 }
static SDL_AudioDeviceID open_audio_device(const char *devname, int iscapture, const SDL_AudioSpec *desired, SDL_AudioSpec *obtained, int allowed_changes, int min_id)
Definition: SDL_audio.c:962
void SDL_PauseAudio ( int  pause_on)

Definition at line 1290 of file SDL_audio.c.

References SDL_PauseAudioDevice().

1291 {
1292  SDL_PauseAudioDevice(1, pause_on);
1293 }
void SDL_PauseAudioDevice(SDL_AudioDeviceID devid, int pause_on)
Definition: SDL_audio.c:1279
void SDL_PauseAudioDevice ( SDL_AudioDeviceID  dev,
int  pause_on 
)

Definition at line 1279 of file SDL_audio.c.

References get_audio_device(), SDL_AudioDriver::impl, SDL_AudioDriverImpl::LockDevice, SDL_AudioDevice::paused, and SDL_AudioDriverImpl::UnlockDevice.

Referenced by SDL_PauseAudio().

1280 {
1281  SDL_AudioDevice *device = get_audio_device(devid);
1282  if (device) {
1283  current_audio.impl.LockDevice(device);
1284  device->paused = pause_on;
1286  }
1287 }
static SDL_AudioDriver current_audio
Definition: SDL_audio.c:33
void(* UnlockDevice)(_THIS)
Definition: SDL_sysaudio.h:81
void(* LockDevice)(_THIS)
Definition: SDL_sysaudio.h:80
SDL_AudioDriverImpl impl
Definition: SDL_sysaudio.h:120
static SDL_AudioDevice * get_audio_device(SDL_AudioDeviceID id)
Definition: SDL_audio.c:150
int SDL_QueueAudio ( SDL_AudioDeviceID  dev,
const void data,
Uint32  len 
)

Queue more audio on non-callback devices.

SDL offers two ways to feed audio to the device: you can either supply a callback that SDL triggers with some frequency to obtain more audio (pull method), or you can supply no callback, and then SDL will expect you to supply data at regular intervals (push method) with this function.

There are no limits on the amount of data you can queue, short of exhaustion of address space. Queued data will drain to the device as necessary without further intervention from you. If the device needs audio but there is not enough queued, it will play silence to make up the difference. This means you will have skips in your audio playback if you aren't routinely queueing sufficient data.

This function copies the supplied data, so you are safe to free it when the function returns. This function is thread-safe, but queueing to the same device from two threads at once does not promise which buffer will be queued first.

You may not queue audio on a device that is using an application-supplied callback; doing so returns an error. You have to use the audio callback or queue audio with this function, but not both.

You should not call SDL_LockAudio() on the device before queueing; SDL handles locking internally for this function.

Parameters
devThe device ID to which we will queue audio.
dataThe data to queue to the device for later playback.
lenThe number of bytes (not samples!) to which (data) points.
Returns
zero on success, -1 on error.
See also
SDL_GetQueuedAudioSize
SDL_ClearQueuedAudio

Definition at line 475 of file SDL_audio.c.

References SDL_AudioDevice::buffer_queue_head, SDL_AudioDevice::buffer_queue_pool, SDL_AudioDevice::buffer_queue_tail, SDL_AudioSpec::callback, SDL_AudioBufferQueue::data, SDL_AudioBufferQueue::datalen, free_audio_queue(), get_audio_device(), SDL_AudioDriver::impl, SDL_AudioDriverImpl::LockDevice, SDL_AudioBufferQueue::next, NULL, SDL_AudioDevice::queued_bytes, SDL_assert, SDL_AUDIOBUFFERQUEUE_PACKETLEN, SDL_BufferQueueDrainCallback(), SDL_malloc, SDL_memcpy, SDL_min, SDL_OutOfMemory, SDL_SetError, SDL_AudioDevice::spec, SDL_AudioBufferQueue::startpos, and SDL_AudioDriverImpl::UnlockDevice.

476 {
477  SDL_AudioDevice *device = get_audio_device(devid);
478  const Uint8 *data = (const Uint8 *) _data;
479  SDL_AudioBufferQueue *orighead;
480  SDL_AudioBufferQueue *origtail;
481  Uint32 origlen;
482  Uint32 datalen;
483 
484  if (!device) {
485  return -1; /* get_audio_device() will have set the error state */
486  }
487 
488  if (device->spec.callback != SDL_BufferQueueDrainCallback) {
489  return SDL_SetError("Audio device has a callback, queueing not allowed");
490  }
491 
492  current_audio.impl.LockDevice(device);
493 
494  orighead = device->buffer_queue_head;
495  origtail = device->buffer_queue_tail;
496  origlen = origtail ? origtail->datalen : 0;
497 
498  while (len > 0) {
499  SDL_AudioBufferQueue *packet = device->buffer_queue_tail;
500  SDL_assert(!packet || (packet->datalen <= SDL_AUDIOBUFFERQUEUE_PACKETLEN));
501  if (!packet || (packet->datalen >= SDL_AUDIOBUFFERQUEUE_PACKETLEN)) {
502  /* tail packet missing or completely full; we need a new packet. */
503  packet = device->buffer_queue_pool;
504  if (packet != NULL) {
505  /* we have one available in the pool. */
506  device->buffer_queue_pool = packet->next;
507  } else {
508  /* Have to allocate a new one! */
510  if (packet == NULL) {
511  /* uhoh, reset so we've queued nothing new, free what we can. */
512  if (!origtail) {
513  packet = device->buffer_queue_head; /* whole queue. */
514  } else {
515  packet = origtail->next; /* what we added to existing queue. */
516  origtail->next = NULL;
517  origtail->datalen = origlen;
518  }
519  device->buffer_queue_head = orighead;
520  device->buffer_queue_tail = origtail;
521  device->buffer_queue_pool = NULL;
522 
524 
525  free_audio_queue(packet); /* give back what we can. */
526 
527  return SDL_OutOfMemory();
528  }
529  }
530  packet->datalen = 0;
531  packet->startpos = 0;
532  packet->next = NULL;
533 
534  SDL_assert((device->buffer_queue_head != NULL) == (device->queued_bytes != 0));
535  if (device->buffer_queue_tail == NULL) {
536  device->buffer_queue_head = packet;
537  } else {
538  device->buffer_queue_tail->next = packet;
539  }
540  device->buffer_queue_tail = packet;
541  }
542 
543  datalen = SDL_min(len, SDL_AUDIOBUFFERQUEUE_PACKETLEN - packet->datalen);
544  SDL_memcpy(packet->data + packet->datalen, data, datalen);
545  data += datalen;
546  len -= datalen;
547  packet->datalen += datalen;
548  device->queued_bytes += datalen;
549  }
550 
552 
553  return 0;
554 }
#define SDL_min(x, y)
Definition: SDL_stdinc.h:345
uint32_t Uint32
An unsigned 32-bit integer type.
Definition: SDL_stdinc.h:155
GLint GLenum GLsizei GLsizei GLsizei GLint GLsizei const GLvoid * data
Definition: SDL_opengl.h:1967
SDL_AudioBufferQueue * buffer_queue_pool
Definition: SDL_sysaudio.h:180
SDL_AudioSpec spec
Definition: SDL_sysaudio.h:150
static SDL_AudioDriver current_audio
Definition: SDL_audio.c:33
void(* UnlockDevice)(_THIS)
Definition: SDL_sysaudio.h:81
GLenum GLsizei len
SDL_AudioBufferQueue * buffer_queue_head
Definition: SDL_sysaudio.h:178
SDL_AudioBufferQueue * buffer_queue_tail
Definition: SDL_sysaudio.h:179
#define SDL_memcpy
struct SDL_AudioBufferQueue * next
Definition: SDL_sysaudio.h:66
uint8_t Uint8
An unsigned 8-bit integer type.
Definition: SDL_stdinc.h:139
SDL_AudioCallback callback
Definition: SDL_audio.h:177
void(* LockDevice)(_THIS)
Definition: SDL_sysaudio.h:80
#define SDL_assert(condition)
Definition: SDL_assert.h:167
#define NULL
Definition: begin_code.h:143
#define SDL_OutOfMemory()
Definition: SDL_error.h:52
static void free_audio_queue(SDL_AudioBufferQueue *buffer)
Definition: SDL_audio.c:423
#define SDL_SetError
SDL_AudioDriverImpl impl
Definition: SDL_sysaudio.h:120
Uint8 data[SDL_AUDIOBUFFERQUEUE_PACKETLEN]
Definition: SDL_sysaudio.h:63
#define SDL_malloc
#define SDL_AUDIOBUFFERQUEUE_PACKETLEN
Definition: SDL_sysaudio.h:58
static void SDL_BufferQueueDrainCallback(void *userdata, Uint8 *stream, int _len)
Definition: SDL_audio.c:433
static SDL_AudioDevice * get_audio_device(SDL_AudioDeviceID id)
Definition: SDL_audio.c:150
void SDL_UnlockAudio ( void  )

Definition at line 1323 of file SDL_audio.c.

References SDL_UnlockAudioDevice().

1324 {
1326 }
void SDL_UnlockAudioDevice(SDL_AudioDeviceID devid)
Definition: SDL_audio.c:1313
void SDL_UnlockAudioDevice ( SDL_AudioDeviceID  dev)

Definition at line 1313 of file SDL_audio.c.

References get_audio_device(), SDL_AudioDriver::impl, and SDL_AudioDriverImpl::UnlockDevice.

Referenced by SDL_UnlockAudio().

1314 {
1315  /* Obtain a lock on the mixing buffers */
1316  SDL_AudioDevice *device = get_audio_device(devid);
1317  if (device) {
1319  }
1320 }
static SDL_AudioDriver current_audio
Definition: SDL_audio.c:33
void(* UnlockDevice)(_THIS)
Definition: SDL_sysaudio.h:81
SDL_AudioDriverImpl impl
Definition: SDL_sysaudio.h:120
static SDL_AudioDevice * get_audio_device(SDL_AudioDeviceID id)
Definition: SDL_audio.c:150