Mercurial > sdl-ios-xcode
annotate docs/html/sdlloadwav.html @ 765:4c2ba6161939
Editors Note: The original patch was modified to use SDL_Delay() instead of
nanosleep because nanosleep may not be portable to all systems
using SDL with the ALSA backend. This may be a moot point with
the switch to blocking writes anyway...
Date: Sat, 27 Dec 2003 21:47:36 +0100
From: Michel Daenzer
To: Debian Bug Tracking System
Subject: [SDL] Bug#225252: [PATCH] ALSA fixes
Package: libsdl1.2debian-all
Version: 1.2.6-2
Severity: normal
Tags: patch
For SDL 1.2.6, the ALSA backend was changed to call snd_pcm_open() with
SND_PCM_NONBLOCK. That's a good idea per se, however, it causes high CPU
usage, interrupted sound and stuttering in some games here. Taking a nanosleep
whenever snd_pcm_writei() returns -EAGAIN fixes this, but I think it's more
efficient to use blocking mode for the actual sound playback. Feedback from the
SDL and ALSA lists appreciated.
The patch also fixes the default ALSA device to be used.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 04 Jan 2004 15:40:50 +0000 |
| parents | e5bc29de3f0a |
| children | 355632dca928 |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_LoadWAV</TITLE | |
| 5 ><META | |
| 6 NAME="GENERATOR" | |
|
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.64 |
| 0 | 8 "><LINK |
| 9 REL="HOME" | |
| 10 TITLE="SDL Library Documentation" | |
| 11 HREF="index.html"><LINK | |
| 12 REL="UP" | |
| 13 TITLE="Audio" | |
| 14 HREF="audio.html"><LINK | |
| 15 REL="PREVIOUS" | |
| 16 TITLE="SDL_GetAudioStatus" | |
| 17 HREF="sdlgetaudiostatus.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_FreeWAV" | |
| 20 HREF="sdlfreewav.html"></HEAD | |
| 21 ><BODY | |
| 22 CLASS="REFENTRY" | |
| 23 BGCOLOR="#FFF8DC" | |
| 24 TEXT="#000000" | |
| 25 LINK="#0000ee" | |
| 26 VLINK="#551a8b" | |
| 27 ALINK="#ff0000" | |
| 28 ><DIV | |
| 29 CLASS="NAVHEADER" | |
| 30 ><TABLE | |
| 31 WIDTH="100%" | |
| 32 BORDER="0" | |
| 33 CELLPADDING="0" | |
| 34 CELLSPACING="0" | |
| 35 ><TR | |
| 36 ><TH | |
| 37 COLSPAN="3" | |
| 38 ALIGN="center" | |
| 39 >SDL Library Documentation</TH | |
| 40 ></TR | |
| 41 ><TR | |
| 42 ><TD | |
| 43 WIDTH="10%" | |
| 44 ALIGN="left" | |
| 45 VALIGN="bottom" | |
| 46 ><A | |
| 47 HREF="sdlgetaudiostatus.html" | |
| 48 >Prev</A | |
| 49 ></TD | |
| 50 ><TD | |
| 51 WIDTH="80%" | |
| 52 ALIGN="center" | |
| 53 VALIGN="bottom" | |
| 54 ></TD | |
| 55 ><TD | |
| 56 WIDTH="10%" | |
| 57 ALIGN="right" | |
| 58 VALIGN="bottom" | |
| 59 ><A | |
| 60 HREF="sdlfreewav.html" | |
| 61 >Next</A | |
| 62 ></TD | |
| 63 ></TR | |
| 64 ></TABLE | |
| 65 ><HR | |
| 66 ALIGN="LEFT" | |
| 67 WIDTH="100%"></DIV | |
| 68 ><H1 | |
| 69 ><A | |
| 70 NAME="SDLLOADWAV" | |
| 71 >SDL_LoadWAV</A | |
| 72 ></H1 | |
| 73 ><DIV | |
| 74 CLASS="REFNAMEDIV" | |
| 75 ><A | |
|
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76 NAME="AEN6428" |
| 0 | 77 ></A |
| 78 ><H2 | |
| 79 >Name</H2 | |
| 80 >SDL_LoadWAV -- Load a WAVE file</DIV | |
| 81 ><DIV | |
| 82 CLASS="REFSYNOPSISDIV" | |
| 83 ><A | |
|
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84 NAME="AEN6431" |
| 0 | 85 ></A |
| 86 ><H2 | |
| 87 >Synopsis</H2 | |
| 88 ><DIV | |
| 89 CLASS="FUNCSYNOPSIS" | |
| 90 ><A | |
|
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91 NAME="AEN6432" |
| 0 | 92 ></A |
| 93 ><P | |
| 94 ></P | |
| 95 ><PRE | |
| 96 CLASS="FUNCSYNOPSISINFO" | |
| 97 >#include "SDL.h"</PRE | |
| 98 ><P | |
| 99 ><CODE | |
| 100 ><CODE | |
| 101 CLASS="FUNCDEF" | |
| 102 >SDL_AudioSpec *<B | |
| 103 CLASS="FSFUNC" | |
| 104 >SDL_LoadWAV</B | |
| 105 ></CODE | |
| 106 >(const char *file, SDL_AudioSpec *spec, Uint8 **audio_buf, Uint32 *audio_len);</CODE | |
| 107 ></P | |
| 108 ><P | |
| 109 ></P | |
| 110 ></DIV | |
| 111 ></DIV | |
| 112 ><DIV | |
| 113 CLASS="REFSECT1" | |
| 114 ><A | |
|
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115 NAME="AEN6438" |
| 0 | 116 ></A |
| 117 ><H2 | |
| 118 >Description</H2 | |
| 119 ><P | |
| 120 ><TT | |
| 121 CLASS="FUNCTION" | |
| 122 >SDL_LoadWAV</TT | |
| 123 > | |
| 124 This function loads a WAVE <TT | |
| 125 CLASS="PARAMETER" | |
| 126 ><I | |
| 127 >file</I | |
| 128 ></TT | |
| 129 > into memory.</P | |
| 130 ><P | |
| 131 >If this function succeeds, it returns the given | |
| 132 <A | |
| 133 HREF="sdlaudiospec.html" | |
| 134 ><TT | |
| 135 CLASS="FUNCTION" | |
| 136 >SDL_AudioSpec</TT | |
| 137 ></A | |
| 138 >, | |
| 139 filled with the audio data format of the wave data, and sets | |
| 140 <TT | |
| 141 CLASS="PARAMETER" | |
| 142 ><I | |
| 143 >audio_buf</I | |
| 144 ></TT | |
| 145 > to a <TT | |
| 146 CLASS="FUNCTION" | |
| 147 >malloc</TT | |
| 148 >'d | |
| 149 buffer containing the audio data, and sets <TT | |
| 150 CLASS="PARAMETER" | |
| 151 ><I | |
| 152 >audio_len</I | |
| 153 ></TT | |
| 154 > | |
| 155 to the length of that audio buffer, in bytes. You need to free the audio | |
| 156 buffer with <A | |
| 157 HREF="sdlfreewav.html" | |
| 158 ><TT | |
| 159 CLASS="FUNCTION" | |
| 160 >SDL_FreeWAV</TT | |
| 161 ></A | |
| 162 > when you are | |
| 163 done with it.</P | |
| 164 ><P | |
| 165 >This function returns <TT | |
| 166 CLASS="LITERAL" | |
| 167 >NULL</TT | |
| 168 > and sets the SDL | |
| 169 error message if the wave file cannot be opened, uses an unknown data format, | |
| 170 or is corrupt. Currently raw, MS-ADPCM and IMA-ADPCM WAVE files are supported.</P | |
| 171 ></DIV | |
| 172 ><DIV | |
| 173 CLASS="REFSECT1" | |
| 174 ><A | |
|
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175 NAME="AEN6453" |
| 0 | 176 ></A |
| 177 ><H2 | |
| 178 >Example</H2 | |
| 179 ><PRE | |
| 180 CLASS="PROGRAMLISTING" | |
| 181 >SDL_AudioSpec wav_spec; | |
| 182 Uint32 wav_length; | |
| 183 Uint8 *wav_buffer; | |
| 184 | |
| 185 /* Load the WAV */ | |
| 186 if( SDL_LoadWAV("test.wav", &wav_spec, &wav_buffer, &wav_length) == NULL ){ | |
| 187 fprintf(stderr, "Could not open test.wav: %s\n", SDL_GetError()); | |
| 188 exit(-1); | |
| 189 } | |
| 190 . | |
| 191 . | |
| 192 . | |
| 193 /* Do stuff with the WAV */ | |
| 194 . | |
| 195 . | |
| 196 /* Free It */ | |
| 197 SDL_FreeWAV(wav_buffer);</PRE | |
| 198 ></DIV | |
| 199 ><DIV | |
| 200 CLASS="REFSECT1" | |
| 201 ><A | |
|
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202 NAME="AEN6456" |
| 0 | 203 ></A |
| 204 ><H2 | |
| 205 >See Also</H2 | |
| 206 ><P | |
| 207 ><A | |
| 208 HREF="sdlaudiospec.html" | |
| 209 ><SPAN | |
| 210 CLASS="STRUCTNAME" | |
| 211 >SDL_AudioSpec</SPAN | |
| 212 ></A | |
| 213 >, | |
| 214 <A | |
| 215 HREF="sdlopenaudio.html" | |
| 216 ><TT | |
| 217 CLASS="FUNCTION" | |
| 218 >SDL_OpenAudio</TT | |
| 219 ></A | |
| 220 >, | |
| 221 <A | |
| 222 HREF="sdlfreewav.html" | |
| 223 ><TT | |
| 224 CLASS="FUNCTION" | |
| 225 >SDL_FreeWAV</TT | |
| 226 ></A | |
| 227 ></P | |
| 228 ></DIV | |
| 229 ><DIV | |
| 230 CLASS="NAVFOOTER" | |
| 231 ><HR | |
| 232 ALIGN="LEFT" | |
| 233 WIDTH="100%"><TABLE | |
| 234 WIDTH="100%" | |
| 235 BORDER="0" | |
| 236 CELLPADDING="0" | |
| 237 CELLSPACING="0" | |
| 238 ><TR | |
| 239 ><TD | |
| 240 WIDTH="33%" | |
| 241 ALIGN="left" | |
| 242 VALIGN="top" | |
| 243 ><A | |
| 244 HREF="sdlgetaudiostatus.html" | |
| 245 >Prev</A | |
| 246 ></TD | |
| 247 ><TD | |
| 248 WIDTH="34%" | |
| 249 ALIGN="center" | |
| 250 VALIGN="top" | |
| 251 ><A | |
| 252 HREF="index.html" | |
| 253 >Home</A | |
| 254 ></TD | |
| 255 ><TD | |
| 256 WIDTH="33%" | |
| 257 ALIGN="right" | |
| 258 VALIGN="top" | |
| 259 ><A | |
| 260 HREF="sdlfreewav.html" | |
| 261 >Next</A | |
| 262 ></TD | |
| 263 ></TR | |
| 264 ><TR | |
| 265 ><TD | |
| 266 WIDTH="33%" | |
| 267 ALIGN="left" | |
| 268 VALIGN="top" | |
| 269 >SDL_GetAudioStatus</TD | |
| 270 ><TD | |
| 271 WIDTH="34%" | |
| 272 ALIGN="center" | |
| 273 VALIGN="top" | |
| 274 ><A | |
| 275 HREF="audio.html" | |
| 276 >Up</A | |
| 277 ></TD | |
| 278 ><TD | |
| 279 WIDTH="33%" | |
| 280 ALIGN="right" | |
| 281 VALIGN="top" | |
| 282 >SDL_FreeWAV</TD | |
| 283 ></TR | |
| 284 ></TABLE | |
| 285 ></DIV | |
| 286 ></BODY | |
| 287 ></HTML | |
| 288 > |