Mercurial > sdl-ios-xcode
annotate docs/html/audio.html @ 2866:e532417a6977
Fixed SDL 1.2 compatibility problem.
The API specifies that SDL_OpenAudio() will fill out the 'desired' audio spec
with the correct samples and size set by the driver. This value is important
since it may be used by applications that size audio buffers, etc.
However, we want to allow advanced applications to call SDL_OpenAudioDevice()
which gets passed a const 'desired' parameter, and have the correct data filled
into the 'obtained' parameter, possibly allowing or not allowing format changes.
So... 'obtained' becomes the audio format the user callback is expected to use,
and we add flags to allow the application to specify which format changes are
allowed.
Note: We really need to add a way to query the 'obtained' audio spec.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sat, 13 Dec 2008 06:36:47 +0000 |
| parents | 355632dca928 |
| children |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >Audio</TITLE | |
| 5 ><META | |
| 6 NAME="GENERATOR" | |
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ |
| 0 | 8 "><LINK |
| 9 REL="HOME" | |
| 10 TITLE="SDL Library Documentation" | |
| 11 HREF="index.html"><LINK | |
| 12 REL="UP" | |
| 13 TITLE="SDL Reference" | |
| 14 HREF="reference.html"><LINK | |
| 15 REL="PREVIOUS" | |
| 16 TITLE="SDL_JoystickClose" | |
| 17 HREF="sdljoystickclose.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_AudioSpec" | |
| 20 HREF="sdlaudiospec.html"><META | |
| 21 NAME="KEYWORD" | |
| 22 CONTENT="audio"><META | |
| 23 NAME="KEYWORD" | |
| 24 CONTENT="function"></HEAD | |
| 25 ><BODY | |
| 26 CLASS="CHAPTER" | |
| 27 BGCOLOR="#FFF8DC" | |
| 28 TEXT="#000000" | |
| 29 LINK="#0000ee" | |
| 30 VLINK="#551a8b" | |
| 31 ALINK="#ff0000" | |
| 32 ><DIV | |
| 33 CLASS="NAVHEADER" | |
| 34 ><TABLE | |
|
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35 SUMMARY="Header navigation table" |
| 0 | 36 WIDTH="100%" |
| 37 BORDER="0" | |
| 38 CELLPADDING="0" | |
| 39 CELLSPACING="0" | |
| 40 ><TR | |
| 41 ><TH | |
| 42 COLSPAN="3" | |
| 43 ALIGN="center" | |
| 44 >SDL Library Documentation</TH | |
| 45 ></TR | |
| 46 ><TR | |
| 47 ><TD | |
| 48 WIDTH="10%" | |
| 49 ALIGN="left" | |
| 50 VALIGN="bottom" | |
| 51 ><A | |
| 52 HREF="sdljoystickclose.html" | |
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53 ACCESSKEY="P" |
| 0 | 54 >Prev</A |
| 55 ></TD | |
| 56 ><TD | |
| 57 WIDTH="80%" | |
| 58 ALIGN="center" | |
| 59 VALIGN="bottom" | |
| 60 ></TD | |
| 61 ><TD | |
| 62 WIDTH="10%" | |
| 63 ALIGN="right" | |
| 64 VALIGN="bottom" | |
| 65 ><A | |
| 66 HREF="sdlaudiospec.html" | |
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67 ACCESSKEY="N" |
| 0 | 68 >Next</A |
| 69 ></TD | |
| 70 ></TR | |
| 71 ></TABLE | |
| 72 ><HR | |
| 73 ALIGN="LEFT" | |
| 74 WIDTH="100%"></DIV | |
| 75 ><DIV | |
| 76 CLASS="CHAPTER" | |
| 77 ><H1 | |
| 78 ><A | |
| 79 NAME="AUDIO" | |
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80 ></A |
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81 >Chapter 10. Audio</H1 |
| 0 | 82 ><DIV |
| 83 CLASS="TOC" | |
| 84 ><DL | |
| 85 ><DT | |
| 86 ><B | |
| 87 >Table of Contents</B | |
| 88 ></DT | |
| 89 ><DT | |
| 90 ><A | |
| 91 HREF="sdlaudiospec.html" | |
| 92 >SDL_AudioSpec</A | |
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93 > -- Audio Specification Structure</DT |
| 0 | 94 ><DT |
| 95 ><A | |
| 96 HREF="sdlopenaudio.html" | |
| 97 >SDL_OpenAudio</A | |
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98 > -- Opens the audio device with the desired parameters.</DT |
| 0 | 99 ><DT |
| 100 ><A | |
| 101 HREF="sdlpauseaudio.html" | |
| 102 >SDL_PauseAudio</A | |
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103 > -- Pauses and unpauses the audio callback processing</DT |
| 0 | 104 ><DT |
| 105 ><A | |
| 106 HREF="sdlgetaudiostatus.html" | |
| 107 >SDL_GetAudioStatus</A | |
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108 > -- Get the current audio state</DT |
| 0 | 109 ><DT |
| 110 ><A | |
| 111 HREF="sdlloadwav.html" | |
| 112 >SDL_LoadWAV</A | |
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113 > -- Load a WAVE file</DT |
| 0 | 114 ><DT |
| 115 ><A | |
| 116 HREF="sdlfreewav.html" | |
| 117 >SDL_FreeWAV</A | |
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118 > -- Frees previously opened WAV data</DT |
| 0 | 119 ><DT |
| 120 ><A | |
| 121 HREF="sdlaudiocvt.html" | |
| 122 >SDL_AudioCVT</A | |
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123 > -- Audio Conversion Structure</DT |
| 0 | 124 ><DT |
| 125 ><A | |
| 126 HREF="sdlbuildaudiocvt.html" | |
| 127 >SDL_BuildAudioCVT</A | |
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128 > -- Initializes a SDL_AudioCVT structure for conversion</DT |
| 0 | 129 ><DT |
| 130 ><A | |
| 131 HREF="sdlconvertaudio.html" | |
| 132 >SDL_ConvertAudio</A | |
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133 > -- Convert audio data to a desired audio format.</DT |
| 0 | 134 ><DT |
| 135 ><A | |
| 136 HREF="sdlmixaudio.html" | |
| 137 >SDL_MixAudio</A | |
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138 > -- Mix audio data</DT |
| 0 | 139 ><DT |
| 140 ><A | |
| 141 HREF="sdllockaudio.html" | |
| 142 >SDL_LockAudio</A | |
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143 > -- Lock out the callback function</DT |
| 0 | 144 ><DT |
| 145 ><A | |
| 146 HREF="sdlunlockaudio.html" | |
| 147 >SDL_UnlockAudio</A | |
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148 > -- Unlock the callback function</DT |
| 0 | 149 ><DT |
| 150 ><A | |
| 151 HREF="sdlcloseaudio.html" | |
| 152 >SDL_CloseAudio</A | |
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153 > -- Shuts down audio processing and closes the audio device.</DT |
| 0 | 154 ></DL |
| 155 ></DIV | |
| 156 ><P | |
| 157 >Sound on the computer is translated from waves that you hear into a series of | |
| 158 values, or samples, each representing the amplitude of the wave. When these | |
| 159 samples are sent in a stream to a sound card, an approximation of the original | |
| 160 wave can be recreated. The more bits used to represent the amplitude, and the | |
| 161 greater frequency these samples are gathered, the closer the approximated | |
| 162 sound is to the original, and the better the quality of sound.</P | |
| 163 ><P | |
| 164 >This library supports both 8 and 16 bit signed and unsigned sound samples, | |
| 165 at frequencies ranging from 11025 Hz to 44100 Hz, depending on the | |
| 166 underlying hardware. If the hardware doesn't support the desired audio | |
| 167 format or frequency, it can be emulated if desired (See | |
| 168 <A | |
| 169 HREF="sdlopenaudio.html" | |
| 170 ><TT | |
| 171 CLASS="FUNCTION" | |
| 172 >SDL_OpenAudio()</TT | |
| 173 ></A | |
| 174 >)</P | |
| 175 ><P | |
| 176 >A commonly supported audio format is 16 bits per sample at 22050 Hz.</P | |
| 177 ></DIV | |
| 178 ><DIV | |
| 179 CLASS="NAVFOOTER" | |
| 180 ><HR | |
| 181 ALIGN="LEFT" | |
| 182 WIDTH="100%"><TABLE | |
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183 SUMMARY="Footer navigation table" |
| 0 | 184 WIDTH="100%" |
| 185 BORDER="0" | |
| 186 CELLPADDING="0" | |
| 187 CELLSPACING="0" | |
| 188 ><TR | |
| 189 ><TD | |
| 190 WIDTH="33%" | |
| 191 ALIGN="left" | |
| 192 VALIGN="top" | |
| 193 ><A | |
| 194 HREF="sdljoystickclose.html" | |
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195 ACCESSKEY="P" |
| 0 | 196 >Prev</A |
| 197 ></TD | |
| 198 ><TD | |
| 199 WIDTH="34%" | |
| 200 ALIGN="center" | |
| 201 VALIGN="top" | |
| 202 ><A | |
| 203 HREF="index.html" | |
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204 ACCESSKEY="H" |
| 0 | 205 >Home</A |
| 206 ></TD | |
| 207 ><TD | |
| 208 WIDTH="33%" | |
| 209 ALIGN="right" | |
| 210 VALIGN="top" | |
| 211 ><A | |
| 212 HREF="sdlaudiospec.html" | |
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213 ACCESSKEY="N" |
| 0 | 214 >Next</A |
| 215 ></TD | |
| 216 ></TR | |
| 217 ><TR | |
| 218 ><TD | |
| 219 WIDTH="33%" | |
| 220 ALIGN="left" | |
| 221 VALIGN="top" | |
| 222 >SDL_JoystickClose</TD | |
| 223 ><TD | |
| 224 WIDTH="34%" | |
| 225 ALIGN="center" | |
| 226 VALIGN="top" | |
| 227 ><A | |
| 228 HREF="reference.html" | |
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229 ACCESSKEY="U" |
| 0 | 230 >Up</A |
| 231 ></TD | |
| 232 ><TD | |
| 233 WIDTH="33%" | |
| 234 ALIGN="right" | |
| 235 VALIGN="top" | |
| 236 >SDL_AudioSpec</TD | |
| 237 ></TR | |
| 238 ></TABLE | |
| 239 ></DIV | |
| 240 ></BODY | |
| 241 ></HTML | |
| 242 > |