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  4. >SDL_AudioSpec</TITLE
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  19. TITLE="SDL_OpenAudio"
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  36. ><TH
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  39. >SDL Library Documentation</TH
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  43. WIDTH="10%"
  44. ALIGN="left"
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  47. HREF="audio.html"
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  60. HREF="sdlopenaudio.html"
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  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
  76. NAME="AEN5966"
  77. ></A
  78. ><H2
  79. >Name</H2
  80. >SDL_AudioSpec -- Audio Specification Structure</DIV
  81. ><DIV
  82. CLASS="REFSECT1"
  83. ><A
  84. NAME="AEN5969"
  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
  104. NAME="AEN5972"
  105. ></A
  106. ><H2
  107. >Structure Data</H2
  108. ><DIV
  109. CLASS="INFORMALTABLE"
  110. ><A
  111. NAME="AEN5974"
  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
  248. NAME="AEN6009"
  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
  298. NAME="AEN6023"
  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
  502. NAME="AEN6098"
  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
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  533. WIDTH="33%"
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  535. VALIGN="top"
  536. ><A
  537. HREF="audio.html"
  538. >Prev</A
  539. ></TD
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  542. ALIGN="center"
  543. VALIGN="top"
  544. ><A
  545. HREF="index.html"
  546. >Home</A
  547. ></TD
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  553. HREF="sdlopenaudio.html"
  554. >Next</A
  555. ></TD
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  559. WIDTH="33%"
  560. ALIGN="left"
  561. VALIGN="top"
  562. >Audio</TD
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  564. WIDTH="34%"
  565. ALIGN="center"
  566. VALIGN="top"
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  568. HREF="audio.html"
  569. >Up</A
  570. ></TD
  571. ><TD
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  573. ALIGN="right"
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  575. >SDL_OpenAudio</TD
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