Mercurial > sdl-ios-xcode
annotate docs/html/sdlconvertaudio.html @ 693:6c119628180d
Date: Sat, 16 Aug 2003 16:22:56 +0300
From: "Mike Gorchak"
Subject: Package building for QNX6
I'm just completed the package description file for QNX6 - qpg, it is like a\
.spec files for Linux. Please place SDL.qpg.in file in the root of the proj\
ect, where .spec file is placed. And sdl12qpg.diff - just adding the SDL.qpg\
.in. The same for the SDL_image. I'm planning to add .qpg files creation for\
all SDL* projects.
As for shared library building for QNX6. It is very hard to improve the exis\
ting libtool code to support QNX shared libraries. Much easyiest is to remov\
e libtool.m4 code from the acinclude.m4 for those persons, who building shar\
ed libraries for QNX6. I'm described all what they need to do with .so under\
QNX6 in the README.QNX file. And 90% of people used the precompiled librari\
es, so I think it is not big problem :)
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sat, 23 Aug 2003 23:25:46 +0000 |
| parents | e5bc29de3f0a |
| children | 355632dca928 |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_ConvertAudio</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_BuildAudioCVT" | |
| 17 HREF="sdlbuildaudiocvt.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_MixAudio" | |
| 20 HREF="sdlmixaudio.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="sdlbuildaudiocvt.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="sdlmixaudio.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="SDLCONVERTAUDIO" | |
| 71 >SDL_ConvertAudio</A | |
| 72 ></H1 | |
| 73 ><DIV | |
| 74 CLASS="REFNAMEDIV" | |
| 75 ><A | |
|
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76 NAME="AEN6660" |
| 0 | 77 ></A |
| 78 ><H2 | |
| 79 >Name</H2 | |
| 80 >SDL_ConvertAudio -- Convert audio data to a desired audio format.</DIV | |
| 81 ><DIV | |
| 82 CLASS="REFSYNOPSISDIV" | |
| 83 ><A | |
|
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84 NAME="AEN6663" |
| 0 | 85 ></A |
| 86 ><H2 | |
| 87 >Synopsis</H2 | |
| 88 ><DIV | |
| 89 CLASS="FUNCSYNOPSIS" | |
| 90 ><A | |
|
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91 NAME="AEN6664" |
| 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 >int <B | |
| 103 CLASS="FSFUNC" | |
| 104 >SDL_ConvertAudio</B | |
| 105 ></CODE | |
| 106 >(SDL_AudioCVT *cvt);</CODE | |
| 107 ></P | |
| 108 ><P | |
| 109 ></P | |
| 110 ></DIV | |
| 111 ></DIV | |
| 112 ><DIV | |
| 113 CLASS="REFSECT1" | |
| 114 ><A | |
|
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115 NAME="AEN6670" |
| 0 | 116 ></A |
| 117 ><H2 | |
| 118 >Description</H2 | |
| 119 ><P | |
| 120 ><TT | |
| 121 CLASS="FUNCTION" | |
| 122 >SDL_ConvertAudio</TT | |
| 123 > takes one parameter, <TT | |
| 124 CLASS="PARAMETER" | |
| 125 ><I | |
| 126 >cvt</I | |
| 127 ></TT | |
| 128 >, which was previously initilized. Initilizing a <A | |
| 129 HREF="sdlaudiocvt.html" | |
| 130 ><SPAN | |
| 131 CLASS="STRUCTNAME" | |
| 132 >SDL_AudioCVT</SPAN | |
| 133 ></A | |
| 134 > is a two step process. First of all, the structure must be passed to <A | |
| 135 HREF="sdlbuildaudiocvt.html" | |
| 136 ><TT | |
| 137 CLASS="FUNCTION" | |
| 138 >SDL_BuildAudioCVT</TT | |
| 139 ></A | |
| 140 > along with source and destination format parameters. Secondly, the <SPAN | |
| 141 CLASS="STRUCTNAME" | |
| 142 >cvt</SPAN | |
| 143 >-><TT | |
| 144 CLASS="STRUCTFIELD" | |
| 145 ><I | |
| 146 >buf</I | |
| 147 ></TT | |
| 148 > and <SPAN | |
| 149 CLASS="STRUCTNAME" | |
| 150 >cvt</SPAN | |
| 151 >-><TT | |
| 152 CLASS="STRUCTFIELD" | |
| 153 ><I | |
| 154 >len</I | |
| 155 ></TT | |
| 156 > fields must be setup. <SPAN | |
| 157 CLASS="STRUCTNAME" | |
| 158 >cvt</SPAN | |
| 159 >-><TT | |
| 160 CLASS="STRUCTFIELD" | |
| 161 ><I | |
| 162 >buf</I | |
| 163 ></TT | |
| 164 > should point to the audio data and <SPAN | |
| 165 CLASS="STRUCTNAME" | |
| 166 >cvt</SPAN | |
| 167 >-><TT | |
| 168 CLASS="STRUCTFIELD" | |
| 169 ><I | |
| 170 >len</I | |
| 171 ></TT | |
| 172 > should be set to the length of the audio data in bytes. Remember, the length of the buffer pointed to by <TT | |
| 173 CLASS="STRUCTFIELD" | |
| 174 ><I | |
| 175 >buf</I | |
| 176 ></TT | |
| 177 > show be <TT | |
| 178 CLASS="STRUCTFIELD" | |
| 179 ><I | |
| 180 >len</I | |
| 181 ></TT | |
| 182 >*<TT | |
| 183 CLASS="STRUCTFIELD" | |
| 184 ><I | |
| 185 >len_mult</I | |
| 186 ></TT | |
| 187 > bytes in length.</P | |
| 188 ><P | |
| 189 >Once the <SPAN | |
| 190 CLASS="STRUCTNAME" | |
| 191 >SDL_AudioCVT</SPAN | |
| 192 >structure is initilized then we can pass it to <TT | |
| 193 CLASS="FUNCTION" | |
| 194 >SDL_ConvertAudio</TT | |
| 195 >, which will convert the audio data pointer to by <SPAN | |
| 196 CLASS="STRUCTNAME" | |
| 197 >cvt</SPAN | |
| 198 >-><TT | |
| 199 CLASS="STRUCTFIELD" | |
| 200 ><I | |
| 201 >buf</I | |
| 202 ></TT | |
| 203 >. If <TT | |
| 204 CLASS="FUNCTION" | |
| 205 >SDL_ConvertAudio</TT | |
| 206 > returned <SPAN | |
| 207 CLASS="RETURNVALUE" | |
| 208 >0</SPAN | |
| 209 > then the conversion was completed successfully, otherwise <SPAN | |
| 210 CLASS="RETURNVALUE" | |
| 211 >-1</SPAN | |
| 212 > is returned.</P | |
| 213 ><P | |
| 214 >If the conversion completed successfully then the converted audio data can be read from <SPAN | |
| 215 CLASS="STRUCTNAME" | |
| 216 >cvt</SPAN | |
| 217 >-><TT | |
| 218 CLASS="STRUCTFIELD" | |
| 219 ><I | |
| 220 >buf</I | |
| 221 ></TT | |
| 222 >. The amount of valid, converted, audio data in the buffer is equal to <SPAN | |
| 223 CLASS="STRUCTNAME" | |
| 224 >cvt</SPAN | |
| 225 >-><TT | |
| 226 CLASS="STRUCTFIELD" | |
| 227 ><I | |
| 228 >len</I | |
| 229 ></TT | |
| 230 >*<TT | |
| 231 CLASS="STRUCTFIELD" | |
| 232 ><I | |
| 233 >cvt</I | |
| 234 ></TT | |
| 235 >-><SPAN | |
| 236 CLASS="STRUCTNAME" | |
| 237 >len_ratio</SPAN | |
| 238 >.</P | |
| 239 ></DIV | |
| 240 ><DIV | |
| 241 CLASS="REFSECT1" | |
| 242 ><A | |
|
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243 NAME="AEN6705" |
| 0 | 244 ></A |
| 245 ><H2 | |
| 246 >Examples</H2 | |
| 247 ><PRE | |
| 248 CLASS="PROGRAMLISTING" | |
| 249 >/* Converting some WAV data to hardware format */ | |
| 250 void my_audio_callback(void *userdata, Uint8 *stream, int len); | |
| 251 | |
| 252 SDL_AudioSpec *desired, *obtained; | |
| 253 SDL_AudioSpec wav_spec; | |
| 254 SDL_AudioCVT wav_cvt; | |
| 255 Uint32 wav_len; | |
| 256 Uint8 *wav_buf; | |
| 257 int ret; | |
| 258 | |
| 259 /* Allocated audio specs */ | |
| 260 desired=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec)); | |
| 261 obtained=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec)); | |
| 262 | |
| 263 /* Set desired format */ | |
| 264 desired->freq=22050; | |
| 265 desired->format=AUDIO_S16LSB; | |
| 266 desired->samples=8192; | |
| 267 desired->callback=my_audio_callback; | |
| 268 desired->userdata=NULL; | |
| 269 | |
| 270 /* Open the audio device */ | |
| 271 if ( SDL_OpenAudio(desired, obtained) < 0 ){ | |
| 272 fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError()); | |
| 273 exit(-1); | |
| 274 } | |
| 275 | |
| 276 free(desired); | |
| 277 | |
| 278 /* Load the test.wav */ | |
| 279 if( SDL_LoadWAV("test.wav", &wav_spec, &wav_buf, &wav_len) == NULL ){ | |
| 280 fprintf(stderr, "Could not open test.wav: %s\n", SDL_GetError()); | |
| 281 SDL_CloseAudio(); | |
| 282 free(obtained); | |
| 283 exit(-1); | |
| 284 } | |
| 285 | |
| 286 /* Build AudioCVT */ | |
| 287 ret = SDL_BuildAudioCVT(&wav_cvt, | |
| 288 wav_spec.format, wav_spec.channels, wav_spec.freq, | |
| 289 obtained->format, obtained->channels, obtained->freq); | |
| 290 | |
| 291 /* Check that the convert was built */ | |
| 292 if(ret==-1){ | |
| 293 fprintf(stderr, "Couldn't build converter!\n"); | |
| 294 SDL_CloseAudio(); | |
| 295 free(obtained); | |
| 296 SDL_FreeWAV(wav_buf); | |
| 297 } | |
| 298 | |
| 299 /* Setup for conversion */ | |
| 300 wav_cvt.buf=(Uint8 *)malloc(wav_len*wav_cvt.len_mult); | |
| 301 wav_cvt.len=wav_len; | |
| 302 memcpy(wav_cvt.buf, wav_buf, wav_len); | |
| 303 | |
| 304 /* We can delete to original WAV data now */ | |
| 305 SDL_FreeWAV(wav_buf); | |
| 306 | |
| 307 /* And now we're ready to convert */ | |
| 308 SDL_ConvertAudio(&wav_cvt); | |
| 309 | |
| 310 /* do whatever */ | |
| 311 . | |
| 312 . | |
| 313 . | |
| 314 . | |
| 315 </PRE | |
| 316 ></DIV | |
| 317 ><DIV | |
| 318 CLASS="REFSECT1" | |
| 319 ><A | |
|
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320 NAME="AEN6708" |
| 0 | 321 ></A |
| 322 ><H2 | |
| 323 >See Also</H2 | |
| 324 ><P | |
| 325 ><A | |
| 326 HREF="sdlbuildaudiocvt.html" | |
| 327 ><TT | |
| 328 CLASS="FUNCTION" | |
| 329 >SDL_BuildAudioCVT</TT | |
| 330 ></A | |
| 331 >, | |
| 332 <A | |
| 333 HREF="sdlaudiocvt.html" | |
| 334 ><TT | |
| 335 CLASS="FUNCTION" | |
| 336 >SDL_AudioCVT</TT | |
| 337 ></A | |
| 338 ></P | |
| 339 ></DIV | |
| 340 ><DIV | |
| 341 CLASS="NAVFOOTER" | |
| 342 ><HR | |
| 343 ALIGN="LEFT" | |
| 344 WIDTH="100%"><TABLE | |
| 345 WIDTH="100%" | |
| 346 BORDER="0" | |
| 347 CELLPADDING="0" | |
| 348 CELLSPACING="0" | |
| 349 ><TR | |
| 350 ><TD | |
| 351 WIDTH="33%" | |
| 352 ALIGN="left" | |
| 353 VALIGN="top" | |
| 354 ><A | |
| 355 HREF="sdlbuildaudiocvt.html" | |
| 356 >Prev</A | |
| 357 ></TD | |
| 358 ><TD | |
| 359 WIDTH="34%" | |
| 360 ALIGN="center" | |
| 361 VALIGN="top" | |
| 362 ><A | |
| 363 HREF="index.html" | |
| 364 >Home</A | |
| 365 ></TD | |
| 366 ><TD | |
| 367 WIDTH="33%" | |
| 368 ALIGN="right" | |
| 369 VALIGN="top" | |
| 370 ><A | |
| 371 HREF="sdlmixaudio.html" | |
| 372 >Next</A | |
| 373 ></TD | |
| 374 ></TR | |
| 375 ><TR | |
| 376 ><TD | |
| 377 WIDTH="33%" | |
| 378 ALIGN="left" | |
| 379 VALIGN="top" | |
| 380 >SDL_BuildAudioCVT</TD | |
| 381 ><TD | |
| 382 WIDTH="34%" | |
| 383 ALIGN="center" | |
| 384 VALIGN="top" | |
| 385 ><A | |
| 386 HREF="audio.html" | |
| 387 >Up</A | |
| 388 ></TD | |
| 389 ><TD | |
| 390 WIDTH="33%" | |
| 391 ALIGN="right" | |
| 392 VALIGN="top" | |
| 393 >SDL_MixAudio</TD | |
| 394 ></TR | |
| 395 ></TABLE | |
| 396 ></DIV | |
| 397 ></BODY | |
| 398 ></HTML | |
| 399 > |