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     71 ><H1
     72 ><A
     73 NAME="SDLAUDIOSPEC"
     74 ></A
     75 >SDL_AudioSpec</H1
     76 ><DIV
     77 CLASS="REFNAMEDIV"
     78 ><A
     79 NAME="AEN6507"
     80 ></A
     81 ><H2
     82 >Name</H2
     83 >SDL_AudioSpec&nbsp;--&nbsp;Audio Specification Structure</DIV
     84 ><DIV
     85 CLASS="REFSECT1"
     86 ><A
     87 NAME="AEN6510"
     88 ></A
     89 ><H2
     90 >Structure Definition</H2
     91 ><PRE
     92 CLASS="PROGRAMLISTING"
     93 >typedef struct{
     94   int freq;
     95   Uint16 format;
     96   Uint8 channels;
     97   Uint8 silence;
     98   Uint16 samples;
     99   Uint32 size;
    100   void (*callback)(void *userdata, Uint8 *stream, int len);
    101   void *userdata;
    102 } SDL_AudioSpec;</PRE
    103 ></DIV
    104 ><DIV
    105 CLASS="REFSECT1"
    106 ><A
    107 NAME="AEN6513"
    108 ></A
    109 ><H2
    110 >Structure Data</H2
    111 ><DIV
    112 CLASS="INFORMALTABLE"
    113 ><A
    114 NAME="AEN6515"
    115 ></A
    116 ><P
    117 ></P
    118 ><TABLE
    119 BORDER="0"
    120 CLASS="CALSTABLE"
    121 ><TBODY
    122 ><TR
    123 ><TD
    124 ALIGN="LEFT"
    125 VALIGN="TOP"
    126 ><TT
    127 CLASS="STRUCTFIELD"
    128 ><I
    129 >freq</I
    130 ></TT
    131 ></TD
    132 ><TD
    133 ALIGN="LEFT"
    134 VALIGN="TOP"
    135 >Audio frequency in samples per second</TD
    136 ></TR
    137 ><TR
    138 ><TD
    139 ALIGN="LEFT"
    140 VALIGN="TOP"
    141 ><TT
    142 CLASS="STRUCTFIELD"
    143 ><I
    144 >format</I
    145 ></TT
    146 ></TD
    147 ><TD
    148 ALIGN="LEFT"
    149 VALIGN="TOP"
    150 >Audio data format</TD
    151 ></TR
    152 ><TR
    153 ><TD
    154 ALIGN="LEFT"
    155 VALIGN="TOP"
    156 ><TT
    157 CLASS="STRUCTFIELD"
    158 ><I
    159 >channels</I
    160 ></TT
    161 ></TD
    162 ><TD
    163 ALIGN="LEFT"
    164 VALIGN="TOP"
    165 >Number of channels: 1 mono, 2 stereo</TD
    166 ></TR
    167 ><TR
    168 ><TD
    169 ALIGN="LEFT"
    170 VALIGN="TOP"
    171 ><TT
    172 CLASS="STRUCTFIELD"
    173 ><I
    174 >silence</I
    175 ></TT
    176 ></TD
    177 ><TD
    178 ALIGN="LEFT"
    179 VALIGN="TOP"
    180 >Audio buffer silence value (calculated)</TD
    181 ></TR
    182 ><TR
    183 ><TD
    184 ALIGN="LEFT"
    185 VALIGN="TOP"
    186 ><TT
    187 CLASS="STRUCTFIELD"
    188 ><I
    189 >samples</I
    190 ></TT
    191 ></TD
    192 ><TD
    193 ALIGN="LEFT"
    194 VALIGN="TOP"
    195 >Audio buffer size in samples</TD
    196 ></TR
    197 ><TR
    198 ><TD
    199 ALIGN="LEFT"
    200 VALIGN="TOP"
    201 ><TT
    202 CLASS="STRUCTFIELD"
    203 ><I
    204 >size</I
    205 ></TT
    206 ></TD
    207 ><TD
    208 ALIGN="LEFT"
    209 VALIGN="TOP"
    210 >Audio buffer size in bytes (calculated)</TD
    211 ></TR
    212 ><TR
    213 ><TD
    214 ALIGN="LEFT"
    215 VALIGN="TOP"
    216 ><TT
    217 CLASS="STRUCTFIELD"
    218 ><I
    219 >callback(..)</I
    220 ></TT
    221 ></TD
    222 ><TD
    223 ALIGN="LEFT"
    224 VALIGN="TOP"
    225 >Callback function for filling the audio buffer</TD
    226 ></TR
    227 ><TR
    228 ><TD
    229 ALIGN="LEFT"
    230 VALIGN="TOP"
    231 ><TT
    232 CLASS="STRUCTFIELD"
    233 ><I
    234 >userdata</I
    235 ></TT
    236 ></TD
    237 ><TD
    238 ALIGN="LEFT"
    239 VALIGN="TOP"
    240 >Pointer the user data which is passed to the callback function</TD
    241 ></TR
    242 ></TBODY
    243 ></TABLE
    244 ><P
    245 ></P
    246 ></DIV
    247 ></DIV
    248 ><DIV
    249 CLASS="REFSECT1"
    250 ><A
    251 NAME="AEN6550"
    252 ></A
    253 ><H2
    254 >Description</H2
    255 ><P
    256 >The <SPAN
    257 CLASS="STRUCTNAME"
    258 >SDL_AudioSpec</SPAN
    259 > structure is used to describe the format of some audio data. This structure is used by <A
    260 HREF="sdlopenaudio.html"
    261 ><TT
    262 CLASS="FUNCTION"
    263 >SDL_OpenAudio</TT
    264 ></A
    265 > and <A
    266 HREF="sdlloadwav.html"
    267 ><TT
    268 CLASS="FUNCTION"
    269 >SDL_LoadWAV</TT
    270 ></A
    271 >. While all fields are used by <TT
    272 CLASS="FUNCTION"
    273 >SDL_OpenAudio</TT
    274 > only <TT
    275 CLASS="STRUCTFIELD"
    276 ><I
    277 >freq</I
    278 ></TT
    279 >, <TT
    280 CLASS="STRUCTFIELD"
    281 ><I
    282 >format</I
    283 ></TT
    284 >, <TT
    285 CLASS="STRUCTFIELD"
    286 ><I
    287 >samples</I
    288 ></TT
    289 > and <TT
    290 CLASS="STRUCTFIELD"
    291 ><I
    292 >channels</I
    293 ></TT
    294 > are used by <TT
    295 CLASS="FUNCTION"
    296 >SDL_LoadWAV</TT
    297 >. We will detail these common members here.</P
    298 ><DIV
    299 CLASS="INFORMALTABLE"
    300 ><A
    301 NAME="AEN6564"
    302 ></A
    303 ><P
    304 ></P
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    306 BORDER="0"
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    308 ><TBODY
    309 ><TR
    310 ><TD
    311 ALIGN="LEFT"
    312 VALIGN="TOP"
    313 ><TT
    314 CLASS="STRUCTFIELD"
    315 ><I
    316 >freq</I
    317 ></TT
    318 ></TD
    319 ><TD
    320 ALIGN="LEFT"
    321 VALIGN="TOP"
    322 ><P
    323 >The number of samples sent to the sound device every second. Common values are 11025, 22050 and 44100. The higher the better.</P
    324 ></TD
    325 ></TR
    326 ><TR
    327 ><TD
    328 ALIGN="LEFT"
    329 VALIGN="TOP"
    330 ><TT
    331 CLASS="STRUCTFIELD"
    332 ><I
    333 >format</I
    334 ></TT
    335 ></TD
    336 ><TD
    337 ALIGN="LEFT"
    338 VALIGN="TOP"
    339 ><P
    340 >Specifies the size and type of each sample element
    341 <P
    342 ></P
    343 ><DIV
    344 CLASS="VARIABLELIST"
    345 ><DL
    346 ><DT
    347 ><TT
    348 CLASS="LITERAL"
    349 >AUDIO_U8</TT
    350 ></DT
    351 ><DD
    352 ><P
    353 >Unsigned 8-bit samples</P
    354 ></DD
    355 ><DT
    356 ><TT
    357 CLASS="LITERAL"
    358 >AUDIO_S8</TT
    359 ></DT
    360 ><DD
    361 ><P
    362 >Signed 8-bit samples</P
    363 ></DD
    364 ><DT
    365 ><TT
    366 CLASS="LITERAL"
    367 >AUDIO_U16</TT
    368 > or <TT
    369 CLASS="LITERAL"
    370 >AUDIO_U16LSB</TT
    371 ></DT
    372 ><DD
    373 ><P
    374 >Unsigned 16-bit little-endian samples</P
    375 ></DD
    376 ><DT
    377 ><TT
    378 CLASS="LITERAL"
    379 >AUDIO_S16</TT
    380 > or <TT
    381 CLASS="LITERAL"
    382 >AUDIO_S16LSB</TT
    383 ></DT
    384 ><DD
    385 ><P
    386 >Signed 16-bit little-endian samples</P
    387 ></DD
    388 ><DT
    389 ><TT
    390 CLASS="LITERAL"
    391 >AUDIO_U16MSB</TT
    392 ></DT
    393 ><DD
    394 ><P
    395 >Unsigned 16-bit big-endian samples</P
    396 ></DD
    397 ><DT
    398 ><TT
    399 CLASS="LITERAL"
    400 >AUDIO_S16MSB</TT
    401 ></DT
    402 ><DD
    403 ><P
    404 >Signed 16-bit big-endian samples</P
    405 ></DD
    406 ><DT
    407 ><TT
    408 CLASS="LITERAL"
    409 >AUDIO_U16SYS</TT
    410 ></DT
    411 ><DD
    412 ><P
    413 >Either <TT
    414 CLASS="LITERAL"
    415 >AUDIO_U16LSB</TT
    416 > or <TT
    417 CLASS="LITERAL"
    418 >AUDIO_U16MSB</TT
    419 > depending on you systems endianness</P
    420 ></DD
    421 ><DT
    422 ><TT
    423 CLASS="LITERAL"
    424 >AUDIO_S16SYS</TT
    425 ></DT
    426 ><DD
    427 ><P
    428 >Either <TT
    429 CLASS="LITERAL"
    430 >AUDIO_S16LSB</TT
    431 > or <TT
    432 CLASS="LITERAL"
    433 >AUDIO_S16MSB</TT
    434 > depending on you systems endianness</P
    435 ></DD
    436 ></DL
    437 ></DIV
    438 ></P
    439 ></TD
    440 ></TR
    441 ><TR
    442 ><TD
    443 ALIGN="LEFT"
    444 VALIGN="TOP"
    445 ><TT
    446 CLASS="STRUCTFIELD"
    447 ><I
    448 >channels</I
    449 ></TT
    450 ></TD
    451 ><TD
    452 ALIGN="LEFT"
    453 VALIGN="TOP"
    454 >The number of seperate sound channels. 1 is mono (single channel), 2 is stereo (dual channel).</TD
    455 ></TR
    456 ><TR
    457 ><TD
    458 ALIGN="LEFT"
    459 VALIGN="TOP"
    460 ><TT
    461 CLASS="STRUCTFIELD"
    462 ><I
    463 >samples</I
    464 ></TT
    465 ></TD
    466 ><TD
    467 ALIGN="LEFT"
    468 VALIGN="TOP"
    469 >When used with <A
    470 HREF="sdlopenaudio.html"
    471 ><TT
    472 CLASS="FUNCTION"
    473 >SDL_OpenAudio</TT
    474 ></A
    475 > this refers to the size of the audio buffer in samples. A sample a chunk of audio data of the size specified in <TT
    476 CLASS="PARAMETER"
    477 ><I
    478 >format</I
    479 ></TT
    480 > mulitplied by the number of channels. When the <SPAN
    481 CLASS="STRUCTNAME"
    482 >SDL_AudioSpec</SPAN
    483 > is used with <A
    484 HREF="sdlloadwav.html"
    485 ><TT
    486 CLASS="FUNCTION"
    487 >SDL_LoadWAV</TT
    488 ></A
    489 > <TT
    490 CLASS="STRUCTFIELD"
    491 ><I
    492 >samples</I
    493 ></TT
    494 > is set to 4096.</TD
    495 ></TR
    496 ></TBODY
    497 ></TABLE
    498 ><P
    499 ></P
    500 ></DIV
    501 ></DIV
    502 ><DIV
    503 CLASS="REFSECT1"
    504 ><A
    505 NAME="AEN6639"
    506 ></A
    507 ><H2
    508 >See Also</H2
    509 ><P
    510 ><A
    511 HREF="sdlopenaudio.html"
    512 ><TT
    513 CLASS="FUNCTION"
    514 >SDL_OpenAudio</TT
    515 ></A
    516 >,
    517 <A
    518 HREF="sdlloadwav.html"
    519 ><TT
    520 CLASS="FUNCTION"
    521 >SDL_LoadWAV</TT
    522 ></A
    523 ></P
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