Mercurial > sdl-ios-xcode
annotate docs/html/sdlaudiospec.html @ 136:717f739d6ec1
Added hardware stretching code to scale 640x480 to TV resolution
There's a bug of some kind in the 16bpp code. ??
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Wed, 01 Aug 2001 08:41:45 +0000 |
| parents | 55f1f1b3e27d |
| children | e5bc29de3f0a |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_AudioSpec</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="Audio" | |
| 17 HREF="audio.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_OpenAudio" | |
| 20 HREF="sdlopenaudio.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="audio.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="sdlopenaudio.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="SDLAUDIOSPEC" | |
| 71 >SDL_AudioSpec</A | |
| 72 ></H1 | |
| 73 ><DIV | |
| 74 CLASS="REFNAMEDIV" | |
| 75 ><A | |
|
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76 NAME="AEN5960" |
| 0 | 77 ></A |
| 78 ><H2 | |
| 79 >Name</H2 | |
| 80 >SDL_AudioSpec -- Audio Specification Structure</DIV | |
| 81 ><DIV | |
| 82 CLASS="REFSECT1" | |
| 83 ><A | |
|
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|
84 NAME="AEN5963" |
| 0 | 85 ></A |
| 86 ><H2 | |
| 87 >Structure Definition</H2 | |
| 88 ><PRE | |
| 89 CLASS="PROGRAMLISTING" | |
| 90 >typedef struct{ | |
| 91 int freq; | |
| 92 Uint16 format; | |
| 93 Uint8 channels; | |
| 94 Uint8 silence; | |
| 95 Uint16 samples; | |
| 96 Uint32 size; | |
| 97 void (*callback)(void *userdata, Uint8 *stream, int len); | |
| 98 void *userdata; | |
| 99 } SDL_AudioSpec;</PRE | |
| 100 ></DIV | |
| 101 ><DIV | |
| 102 CLASS="REFSECT1" | |
| 103 ><A | |
|
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104 NAME="AEN5966" |
| 0 | 105 ></A |
| 106 ><H2 | |
| 107 >Structure Data</H2 | |
| 108 ><DIV | |
| 109 CLASS="INFORMALTABLE" | |
| 110 ><A | |
|
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111 NAME="AEN5968" |
| 0 | 112 ></A |
| 113 ><P | |
| 114 ></P | |
| 115 ><TABLE | |
| 116 BORDER="0" | |
| 117 CLASS="CALSTABLE" | |
| 118 ><TBODY | |
| 119 ><TR | |
| 120 ><TD | |
| 121 ALIGN="LEFT" | |
| 122 VALIGN="TOP" | |
| 123 ><TT | |
| 124 CLASS="STRUCTFIELD" | |
| 125 ><I | |
| 126 >freq</I | |
| 127 ></TT | |
| 128 ></TD | |
| 129 ><TD | |
| 130 ALIGN="LEFT" | |
| 131 VALIGN="TOP" | |
| 132 >Audio frequency in samples per second</TD | |
| 133 ></TR | |
| 134 ><TR | |
| 135 ><TD | |
| 136 ALIGN="LEFT" | |
| 137 VALIGN="TOP" | |
| 138 ><TT | |
| 139 CLASS="STRUCTFIELD" | |
| 140 ><I | |
| 141 >format</I | |
| 142 ></TT | |
| 143 ></TD | |
| 144 ><TD | |
| 145 ALIGN="LEFT" | |
| 146 VALIGN="TOP" | |
| 147 >Audio data format</TD | |
| 148 ></TR | |
| 149 ><TR | |
| 150 ><TD | |
| 151 ALIGN="LEFT" | |
| 152 VALIGN="TOP" | |
| 153 ><TT | |
| 154 CLASS="STRUCTFIELD" | |
| 155 ><I | |
| 156 >channels</I | |
| 157 ></TT | |
| 158 ></TD | |
| 159 ><TD | |
| 160 ALIGN="LEFT" | |
| 161 VALIGN="TOP" | |
| 162 >Number of channels: 1 mono, 2 stereo</TD | |
| 163 ></TR | |
| 164 ><TR | |
| 165 ><TD | |
| 166 ALIGN="LEFT" | |
| 167 VALIGN="TOP" | |
| 168 ><TT | |
| 169 CLASS="STRUCTFIELD" | |
| 170 ><I | |
| 171 >silence</I | |
| 172 ></TT | |
| 173 ></TD | |
| 174 ><TD | |
| 175 ALIGN="LEFT" | |
| 176 VALIGN="TOP" | |
| 177 >Audio buffer silence value (calculated)</TD | |
| 178 ></TR | |
| 179 ><TR | |
| 180 ><TD | |
| 181 ALIGN="LEFT" | |
| 182 VALIGN="TOP" | |
| 183 ><TT | |
| 184 CLASS="STRUCTFIELD" | |
| 185 ><I | |
| 186 >samples</I | |
| 187 ></TT | |
| 188 ></TD | |
| 189 ><TD | |
| 190 ALIGN="LEFT" | |
| 191 VALIGN="TOP" | |
| 192 >Audio buffer size in samples</TD | |
| 193 ></TR | |
| 194 ><TR | |
| 195 ><TD | |
| 196 ALIGN="LEFT" | |
| 197 VALIGN="TOP" | |
| 198 ><TT | |
| 199 CLASS="STRUCTFIELD" | |
| 200 ><I | |
| 201 >size</I | |
| 202 ></TT | |
| 203 ></TD | |
| 204 ><TD | |
| 205 ALIGN="LEFT" | |
| 206 VALIGN="TOP" | |
| 207 >Audio buffer size in bytes (calculated)</TD | |
| 208 ></TR | |
| 209 ><TR | |
| 210 ><TD | |
| 211 ALIGN="LEFT" | |
| 212 VALIGN="TOP" | |
| 213 ><TT | |
| 214 CLASS="STRUCTFIELD" | |
| 215 ><I | |
| 216 >callback(..)</I | |
| 217 ></TT | |
| 218 ></TD | |
| 219 ><TD | |
| 220 ALIGN="LEFT" | |
| 221 VALIGN="TOP" | |
| 222 >Callback function for filling the audio buffer</TD | |
| 223 ></TR | |
| 224 ><TR | |
| 225 ><TD | |
| 226 ALIGN="LEFT" | |
| 227 VALIGN="TOP" | |
| 228 ><TT | |
| 229 CLASS="STRUCTFIELD" | |
| 230 ><I | |
| 231 >userdata</I | |
| 232 ></TT | |
| 233 ></TD | |
| 234 ><TD | |
| 235 ALIGN="LEFT" | |
| 236 VALIGN="TOP" | |
| 237 >Pointer the user data which is passed to the callback function</TD | |
| 238 ></TR | |
| 239 ></TBODY | |
| 240 ></TABLE | |
| 241 ><P | |
| 242 ></P | |
| 243 ></DIV | |
| 244 ></DIV | |
| 245 ><DIV | |
| 246 CLASS="REFSECT1" | |
| 247 ><A | |
|
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55f1f1b3e27d
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Sam Lantinga <slouken@lokigames.com>
parents:
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diff
changeset
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248 NAME="AEN6003" |
| 0 | 249 ></A |
| 250 ><H2 | |
| 251 >Description</H2 | |
| 252 ><P | |
| 253 >The <SPAN | |
| 254 CLASS="STRUCTNAME" | |
| 255 >SDL_AudioSpec</SPAN | |
| 256 > structure is used to describe the format of some audio data. This structure is used by <A | |
| 257 HREF="sdlopenaudio.html" | |
| 258 ><TT | |
| 259 CLASS="FUNCTION" | |
| 260 >SDL_OpenAudio</TT | |
| 261 ></A | |
| 262 > and <A | |
| 263 HREF="sdlloadwav.html" | |
| 264 ><TT | |
| 265 CLASS="FUNCTION" | |
| 266 >SDL_LoadWAV</TT | |
| 267 ></A | |
| 268 >. While all fields are used by <TT | |
| 269 CLASS="FUNCTION" | |
| 270 >SDL_OpenAudio</TT | |
| 271 > only <TT | |
| 272 CLASS="STRUCTFIELD" | |
| 273 ><I | |
| 274 >freq</I | |
| 275 ></TT | |
| 276 >, <TT | |
| 277 CLASS="STRUCTFIELD" | |
| 278 ><I | |
| 279 >format</I | |
| 280 ></TT | |
| 281 >, <TT | |
| 282 CLASS="STRUCTFIELD" | |
| 283 ><I | |
| 284 >samples</I | |
| 285 ></TT | |
| 286 > and <TT | |
| 287 CLASS="STRUCTFIELD" | |
| 288 ><I | |
| 289 >channels</I | |
| 290 ></TT | |
| 291 > are used by <TT | |
| 292 CLASS="FUNCTION" | |
| 293 >SDL_LoadWAV</TT | |
| 294 >. We will detail these common members here.</P | |
| 295 ><DIV | |
| 296 CLASS="INFORMALTABLE" | |
| 297 ><A | |
|
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diff
changeset
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298 NAME="AEN6017" |
| 0 | 299 ></A |
| 300 ><P | |
| 301 ></P | |
| 302 ><TABLE | |
| 303 BORDER="0" | |
| 304 CLASS="CALSTABLE" | |
| 305 ><TBODY | |
| 306 ><TR | |
| 307 ><TD | |
| 308 ALIGN="LEFT" | |
| 309 VALIGN="TOP" | |
| 310 ><TT | |
| 311 CLASS="STRUCTFIELD" | |
| 312 ><I | |
| 313 >freq</I | |
| 314 ></TT | |
| 315 ></TD | |
| 316 ><TD | |
| 317 ALIGN="LEFT" | |
| 318 VALIGN="TOP" | |
| 319 ><P | |
| 320 >The number of samples sent to the sound device every second. Common values are 11025, 22050 and 44100. The higher the better.</P | |
| 321 ></TD | |
| 322 ></TR | |
| 323 ><TR | |
| 324 ><TD | |
| 325 ALIGN="LEFT" | |
| 326 VALIGN="TOP" | |
| 327 ><TT | |
| 328 CLASS="STRUCTFIELD" | |
| 329 ><I | |
| 330 >format</I | |
| 331 ></TT | |
| 332 ></TD | |
| 333 ><TD | |
| 334 ALIGN="LEFT" | |
| 335 VALIGN="TOP" | |
| 336 ><P | |
| 337 >Specifies the size and type of each sample element | |
| 338 <P | |
| 339 ></P | |
| 340 ><DIV | |
| 341 CLASS="VARIABLELIST" | |
| 342 ><DL | |
| 343 ><DT | |
| 344 ><TT | |
| 345 CLASS="LITERAL" | |
| 346 >AUDIO_U8</TT | |
| 347 ></DT | |
| 348 ><DD | |
| 349 ><P | |
| 350 >Unsigned 8-bit samples</P | |
| 351 ></DD | |
| 352 ><DT | |
| 353 ><TT | |
| 354 CLASS="LITERAL" | |
| 355 >AUDIO_S8</TT | |
| 356 ></DT | |
| 357 ><DD | |
| 358 ><P | |
| 359 >Signed 8-bit samples</P | |
| 360 ></DD | |
| 361 ><DT | |
| 362 ><TT | |
| 363 CLASS="LITERAL" | |
| 364 >AUDIO_U16</TT | |
| 365 > or <TT | |
| 366 CLASS="LITERAL" | |
| 367 >AUDIO_U16LSB</TT | |
| 368 ></DT | |
| 369 ><DD | |
| 370 ><P | |
| 371 >Unsigned 16-bit little-endian samples</P | |
| 372 ></DD | |
| 373 ><DT | |
| 374 ><TT | |
| 375 CLASS="LITERAL" | |
| 376 >AUDIO_S16</TT | |
| 377 > or <TT | |
| 378 CLASS="LITERAL" | |
| 379 >AUDIO_S16LSB</TT | |
| 380 ></DT | |
| 381 ><DD | |
| 382 ><P | |
| 383 >Signed 16-bit little-endian samples</P | |
| 384 ></DD | |
| 385 ><DT | |
| 386 ><TT | |
| 387 CLASS="LITERAL" | |
| 388 >AUDIO_U16MSB</TT | |
| 389 ></DT | |
| 390 ><DD | |
| 391 ><P | |
| 392 >Unsigned 16-bit big-endian samples</P | |
| 393 ></DD | |
| 394 ><DT | |
| 395 ><TT | |
| 396 CLASS="LITERAL" | |
| 397 >AUDIO_S16MSB</TT | |
| 398 ></DT | |
| 399 ><DD | |
| 400 ><P | |
| 401 >Signed 16-bit big-endian samples</P | |
| 402 ></DD | |
| 403 ><DT | |
| 404 ><TT | |
| 405 CLASS="LITERAL" | |
| 406 >AUDIO_U16SYS</TT | |
| 407 ></DT | |
| 408 ><DD | |
| 409 ><P | |
| 410 >Either <TT | |
| 411 CLASS="LITERAL" | |
| 412 >AUDIO_U16LSB</TT | |
| 413 > or <TT | |
| 414 CLASS="LITERAL" | |
| 415 >AUDIO_U16MSB</TT | |
| 416 > depending on you systems endianness</P | |
| 417 ></DD | |
| 418 ><DT | |
| 419 ><TT | |
| 420 CLASS="LITERAL" | |
| 421 >AUDIO_S16SYS</TT | |
| 422 ></DT | |
| 423 ><DD | |
| 424 ><P | |
| 425 >Either <TT | |
| 426 CLASS="LITERAL" | |
| 427 >AUDIO_S16LSB</TT | |
| 428 > or <TT | |
| 429 CLASS="LITERAL" | |
| 430 >AUDIO_S16MSB</TT | |
| 431 > depending on you systems endianness</P | |
| 432 ></DD | |
| 433 ></DL | |
| 434 ></DIV | |
| 435 ></P | |
| 436 ></TD | |
| 437 ></TR | |
| 438 ><TR | |
| 439 ><TD | |
| 440 ALIGN="LEFT" | |
| 441 VALIGN="TOP" | |
| 442 ><TT | |
| 443 CLASS="STRUCTFIELD" | |
| 444 ><I | |
| 445 >channels</I | |
| 446 ></TT | |
| 447 ></TD | |
| 448 ><TD | |
| 449 ALIGN="LEFT" | |
| 450 VALIGN="TOP" | |
| 451 >The number of seperate sound channels. 1 is mono (single channel), 2 is stereo (dual channel).</TD | |
| 452 ></TR | |
| 453 ><TR | |
| 454 ><TD | |
| 455 ALIGN="LEFT" | |
| 456 VALIGN="TOP" | |
| 457 ><TT | |
| 458 CLASS="STRUCTFIELD" | |
| 459 ><I | |
| 460 >samples</I | |
| 461 ></TT | |
| 462 ></TD | |
| 463 ><TD | |
| 464 ALIGN="LEFT" | |
| 465 VALIGN="TOP" | |
| 466 >When used with <A | |
| 467 HREF="sdlopenaudio.html" | |
| 468 ><TT | |
| 469 CLASS="FUNCTION" | |
| 470 >SDL_OpenAudio</TT | |
| 471 ></A | |
| 472 > this refers to the size of the audio buffer in samples. A sample a chunk of audio data of the size specified in <TT | |
| 473 CLASS="PARAMETER" | |
| 474 ><I | |
| 475 >format</I | |
| 476 ></TT | |
| 477 > mulitplied by the number of channels. When the <SPAN | |
| 478 CLASS="STRUCTNAME" | |
| 479 >SDL_AudioSpec</SPAN | |
| 480 > is used with <A | |
| 481 HREF="sdlloadwav.html" | |
| 482 ><TT | |
| 483 CLASS="FUNCTION" | |
| 484 >SDL_LoadWAV</TT | |
| 485 ></A | |
| 486 > <TT | |
| 487 CLASS="STRUCTFIELD" | |
| 488 ><I | |
| 489 >samples</I | |
| 490 ></TT | |
| 491 > is set to 4096.</TD | |
| 492 ></TR | |
| 493 ></TBODY | |
| 494 ></TABLE | |
| 495 ><P | |
| 496 ></P | |
| 497 ></DIV | |
| 498 ></DIV | |
| 499 ><DIV | |
| 500 CLASS="REFSECT1" | |
| 501 ><A | |
|
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55f1f1b3e27d
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Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
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502 NAME="AEN6092" |
| 0 | 503 ></A |
| 504 ><H2 | |
| 505 >See Also</H2 | |
| 506 ><P | |
| 507 ><A | |
| 508 HREF="sdlopenaudio.html" | |
| 509 ><TT | |
| 510 CLASS="FUNCTION" | |
| 511 >SDL_OpenAudio</TT | |
| 512 ></A | |
| 513 >, | |
| 514 <A | |
| 515 HREF="sdlloadwav.html" | |
| 516 ><TT | |
| 517 CLASS="FUNCTION" | |
| 518 >SDL_LoadWAV</TT | |
| 519 ></A | |
| 520 ></P | |
| 521 ></DIV | |
| 522 ><DIV | |
| 523 CLASS="NAVFOOTER" | |
| 524 ><HR | |
| 525 ALIGN="LEFT" | |
| 526 WIDTH="100%"><TABLE | |
| 527 WIDTH="100%" | |
| 528 BORDER="0" | |
| 529 CELLPADDING="0" | |
| 530 CELLSPACING="0" | |
| 531 ><TR | |
| 532 ><TD | |
| 533 WIDTH="33%" | |
| 534 ALIGN="left" | |
| 535 VALIGN="top" | |
| 536 ><A | |
| 537 HREF="audio.html" | |
| 538 >Prev</A | |
| 539 ></TD | |
| 540 ><TD | |
| 541 WIDTH="34%" | |
| 542 ALIGN="center" | |
| 543 VALIGN="top" | |
| 544 ><A | |
| 545 HREF="index.html" | |
| 546 >Home</A | |
| 547 ></TD | |
| 548 ><TD | |
| 549 WIDTH="33%" | |
| 550 ALIGN="right" | |
| 551 VALIGN="top" | |
| 552 ><A | |
| 553 HREF="sdlopenaudio.html" | |
| 554 >Next</A | |
| 555 ></TD | |
| 556 ></TR | |
| 557 ><TR | |
| 558 ><TD | |
| 559 WIDTH="33%" | |
| 560 ALIGN="left" | |
| 561 VALIGN="top" | |
| 562 >Audio</TD | |
| 563 ><TD | |
| 564 WIDTH="34%" | |
| 565 ALIGN="center" | |
| 566 VALIGN="top" | |
| 567 ><A | |
| 568 HREF="audio.html" | |
| 569 >Up</A | |
| 570 ></TD | |
| 571 ><TD | |
| 572 WIDTH="33%" | |
| 573 ALIGN="right" | |
| 574 VALIGN="top" | |
| 575 >SDL_OpenAudio</TD | |
| 576 ></TR | |
| 577 ></TABLE | |
| 578 ></DIV | |
| 579 ></BODY | |
| 580 ></HTML | |
| 581 > |