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Ajouts des libs windows
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4 >SDL_ConvertAudio</TITLE
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71 ><H1
72 ><A
73 NAME="SDLCONVERTAUDIO"
74 ></A
75 >SDL_ConvertAudio</H1
76 ><DIV
77 CLASS="REFNAMEDIV"
78 ><A
79 NAME="AEN7048"
80 ></A
81 ><H2
82 >Name</H2
83 >SDL_ConvertAudio&nbsp;--&nbsp;Convert audio data to a desired audio format.</DIV
84 ><DIV
85 CLASS="REFSYNOPSISDIV"
86 ><A
87 NAME="AEN7051"
88 ></A
89 ><H2
90 >Synopsis</H2
91 ><DIV
92 CLASS="FUNCSYNOPSIS"
93 ><A
94 NAME="AEN7052"
95 ></A
96 ><P
97 ></P
98 ><PRE
99 CLASS="FUNCSYNOPSISINFO"
100 >#include "SDL.h"</PRE
101 ><P
102 ><CODE
103 ><CODE
104 CLASS="FUNCDEF"
105 >int <B
106 CLASS="FSFUNC"
107 >SDL_ConvertAudio</B
108 ></CODE
109 >(SDL_AudioCVT *cvt);</CODE
110 ></P
111 ><P
112 ></P
113 ></DIV
114 ></DIV
115 ><DIV
116 CLASS="REFSECT1"
117 ><A
118 NAME="AEN7058"
119 ></A
120 ><H2
121 >Description</H2
122 ><P
123 ><TT
124 CLASS="FUNCTION"
125 >SDL_ConvertAudio</TT
126 > takes one parameter, <TT
127 CLASS="PARAMETER"
128 ><I
129 >cvt</I
130 ></TT
131 >, which was previously initilized. Initilizing a <A
132 HREF="sdlaudiocvt.html"
133 ><SPAN
134 CLASS="STRUCTNAME"
135 >SDL_AudioCVT</SPAN
136 ></A
137 > is a two step process. First of all, the structure must be passed to <A
138 HREF="sdlbuildaudiocvt.html"
139 ><TT
140 CLASS="FUNCTION"
141 >SDL_BuildAudioCVT</TT
142 ></A
143 > along with source and destination format parameters. Secondly, the <SPAN
144 CLASS="STRUCTNAME"
145 >cvt</SPAN
146 >-&#62;<TT
147 CLASS="STRUCTFIELD"
148 ><I
149 >buf</I
150 ></TT
151 > and <SPAN
152 CLASS="STRUCTNAME"
153 >cvt</SPAN
154 >-&#62;<TT
155 CLASS="STRUCTFIELD"
156 ><I
157 >len</I
158 ></TT
159 > fields must be setup. <SPAN
160 CLASS="STRUCTNAME"
161 >cvt</SPAN
162 >-&#62;<TT
163 CLASS="STRUCTFIELD"
164 ><I
165 >buf</I
166 ></TT
167 > should point to the audio data and <SPAN
168 CLASS="STRUCTNAME"
169 >cvt</SPAN
170 >-&#62;<TT
171 CLASS="STRUCTFIELD"
172 ><I
173 >len</I
174 ></TT
175 > should be set to the length of the audio data in bytes. Remember, the length of the buffer pointed to by <TT
176 CLASS="STRUCTFIELD"
177 ><I
178 >buf</I
179 ></TT
180 > show be <TT
181 CLASS="STRUCTFIELD"
182 ><I
183 >len</I
184 ></TT
185 >*<TT
186 CLASS="STRUCTFIELD"
187 ><I
188 >len_mult</I
189 ></TT
190 > bytes in length.</P
191 ><P
192 >Once the <SPAN
193 CLASS="STRUCTNAME"
194 >SDL_AudioCVT</SPAN
195 >structure is initilized then we can pass it to <TT
196 CLASS="FUNCTION"
197 >SDL_ConvertAudio</TT
198 >, which will convert the audio data pointer to by <SPAN
199 CLASS="STRUCTNAME"
200 >cvt</SPAN
201 >-&#62;<TT
202 CLASS="STRUCTFIELD"
203 ><I
204 >buf</I
205 ></TT
206 >. If <TT
207 CLASS="FUNCTION"
208 >SDL_ConvertAudio</TT
209 > returned <SPAN
210 CLASS="RETURNVALUE"
211 >0</SPAN
212 > then the conversion was completed successfully, otherwise <SPAN
213 CLASS="RETURNVALUE"
214 >-1</SPAN
215 > is returned.</P
216 ><P
217 >If the conversion completed successfully then the converted audio data can be read from <SPAN
218 CLASS="STRUCTNAME"
219 >cvt</SPAN
220 >-&#62;<TT
221 CLASS="STRUCTFIELD"
222 ><I
223 >buf</I
224 ></TT
225 >. The amount of valid, converted, audio data in the buffer is equal to <SPAN
226 CLASS="STRUCTNAME"
227 >cvt</SPAN
228 >-&#62;<TT
229 CLASS="STRUCTFIELD"
230 ><I
231 >len</I
232 ></TT
233 >*<TT
234 CLASS="STRUCTFIELD"
235 ><I
236 >cvt</I
237 ></TT
238 >-&#62;<SPAN
239 CLASS="STRUCTNAME"
240 >len_ratio</SPAN
241 >.</P
242 ></DIV
243 ><DIV
244 CLASS="REFSECT1"
245 ><A
246 NAME="AEN7093"
247 ></A
248 ><H2
249 >Examples</H2
250 ><PRE
251 CLASS="PROGRAMLISTING"
252 >/* Converting some WAV data to hardware format */
253 void my_audio_callback(void *userdata, Uint8 *stream, int len);
254
255 SDL_AudioSpec *desired, *obtained;
256 SDL_AudioSpec wav_spec;
257 SDL_AudioCVT wav_cvt;
258 Uint32 wav_len;
259 Uint8 *wav_buf;
260 int ret;
261
262 /* Allocated audio specs */
263 desired = malloc(sizeof(SDL_AudioSpec));
264 obtained = malloc(sizeof(SDL_AudioSpec));
265
266 /* Set desired format */
267 desired-&#62;freq=22050;
268 desired-&#62;format=AUDIO_S16LSB;
269 desired-&#62;samples=8192;
270 desired-&#62;callback=my_audio_callback;
271 desired-&#62;userdata=NULL;
272
273 /* Open the audio device */
274 if ( SDL_OpenAudio(desired, obtained) &#60; 0 ){
275 fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError());
276 exit(-1);
277 }
278
279 free(desired);
280
281 /* Load the test.wav */
282 if( SDL_LoadWAV("test.wav", &#38;wav_spec, &#38;wav_buf, &#38;wav_len) == NULL ){
283 fprintf(stderr, "Could not open test.wav: %s\n", SDL_GetError());
284 SDL_CloseAudio();
285 free(obtained);
286 exit(-1);
287 }
288
289 /* Build AudioCVT */
290 ret = SDL_BuildAudioCVT(&#38;wav_cvt,
291 wav_spec.format, wav_spec.channels, wav_spec.freq,
292 obtained-&#62;format, obtained-&#62;channels, obtained-&#62;freq);
293
294 /* Check that the convert was built */
295 if(ret==-1){
296 fprintf(stderr, "Couldn't build converter!\n");
297 SDL_CloseAudio();
298 free(obtained);
299 SDL_FreeWAV(wav_buf);
300 }
301
302 /* Setup for conversion */
303 wav_cvt.buf = malloc(wav_len * wav_cvt.len_mult);
304 wav_cvt.len = wav_len;
305 memcpy(wav_cvt.buf, wav_buf, wav_len);
306
307 /* We can delete to original WAV data now */
308 SDL_FreeWAV(wav_buf);
309
310 /* And now we're ready to convert */
311 SDL_ConvertAudio(&#38;wav_cvt);
312
313 /* do whatever */
314 .
315 .
316 .
317 .
318 &#13;</PRE
319 ></DIV
320 ><DIV
321 CLASS="REFSECT1"
322 ><A
323 NAME="AEN7096"
324 ></A
325 ><H2
326 >See Also</H2
327 ><P
328 ><A
329 HREF="sdlbuildaudiocvt.html"
330 ><TT
331 CLASS="FUNCTION"
332 >SDL_BuildAudioCVT</TT
333 ></A
334 >,
335 <A
336 HREF="sdlaudiocvt.html"
337 ><TT
338 CLASS="FUNCTION"
339 >SDL_AudioCVT</TT
340 ></A
341 ></P
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