Mercurial > sdl-ios-xcode
annotate docs/man3/SDL_ConvertAudio.3 @ 1795:398ac0f88e4d
Fixed bug #220
The AltiVec blitters don't compile, since they require __VEC__ to be enabled in
order for the compiler to understand "vector" and friends (i.e. do AltiVec)
But you don't want to turn AltiVec on globally, since then the code would only
run on a G4 (there are already runtime tests, before using the AltiVec
variants)
The solution here is to enable AltiVec locally, for the actual AltiVec code.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Tue, 09 May 2006 15:09:47 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
| rev | line source |
|---|---|
|
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
1 .TH "SDL_ConvertAudio" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" |
| 0 | 2 .SH "NAME" |
| 3 SDL_ConvertAudio\- Convert audio data to a desired audio format\&. | |
| 4 .SH "SYNOPSIS" | |
| 5 .PP | |
| 6 \fB#include "SDL\&.h" | |
| 7 .sp | |
| 8 \fBint \fBSDL_ConvertAudio\fP\fR(\fBSDL_AudioCVT *cvt\fR); | |
| 9 .SH "DESCRIPTION" | |
| 10 .PP | |
| 11 \fBSDL_ConvertAudio\fP takes one parameter, \fBcvt\fR, which was previously initilized\&. Initilizing a \fI\fBSDL_AudioCVT\fR\fR is a two step process\&. First of all, the structure must be passed to \fI\fBSDL_BuildAudioCVT\fP\fR along with source and destination format parameters\&. Secondly, the \fBcvt\fR->\fBbuf\fR and \fBcvt\fR->\fBlen\fR fields must be setup\&. \fBcvt\fR->\fBbuf\fR should point to the audio data and \fBcvt\fR->\fBlen\fR should be set to the length of the audio data in bytes\&. Remember, the length of the buffer pointed to by \fBbuf\fR show be \fBlen\fR*\fBlen_mult\fR bytes in length\&. | |
| 12 .PP | |
| 13 Once the \fBSDL_AudioCVT\fRstructure is initilized then we can pass it to \fBSDL_ConvertAudio\fP, which will convert the audio data pointer to by \fBcvt\fR->\fBbuf\fR\&. If \fBSDL_ConvertAudio\fP returned \fB0\fR then the conversion was completed successfully, otherwise \fB-1\fR is returned\&. | |
| 14 .PP | |
| 15 If the conversion completed successfully then the converted audio data can be read from \fBcvt\fR->\fBbuf\fR\&. The amount of valid, converted, audio data in the buffer is equal to \fBcvt\fR->\fBlen\fR*\fBcvt\fR->\fBlen_ratio\fR\&. | |
| 16 .SH "EXAMPLES" | |
| 17 .PP | |
| 18 .nf | |
| 19 \f(CW/* Converting some WAV data to hardware format */ | |
| 20 void my_audio_callback(void *userdata, Uint8 *stream, int len); | |
| 21 | |
| 22 SDL_AudioSpec *desired, *obtained; | |
| 23 SDL_AudioSpec wav_spec; | |
| 24 SDL_AudioCVT wav_cvt; | |
| 25 Uint32 wav_len; | |
| 26 Uint8 *wav_buf; | |
| 27 int ret; | |
| 28 | |
| 29 /* Allocated audio specs */ | |
| 30 desired=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec)); | |
| 31 obtained=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec)); | |
| 32 | |
| 33 /* Set desired format */ | |
| 34 desired->freq=22050; | |
| 35 desired->format=AUDIO_S16LSB; | |
| 36 desired->samples=8192; | |
| 37 desired->callback=my_audio_callback; | |
| 38 desired->userdata=NULL; | |
| 39 | |
| 40 /* Open the audio device */ | |
| 41 if ( SDL_OpenAudio(desired, obtained) < 0 ){ | |
| 42 fprintf(stderr, "Couldn\&'t open audio: %s | |
| 43 ", SDL_GetError()); | |
| 44 exit(-1); | |
| 45 } | |
| 46 | |
| 47 free(desired); | |
| 48 | |
| 49 /* Load the test\&.wav */ | |
| 50 if( SDL_LoadWAV("test\&.wav", &wav_spec, &wav_buf, &wav_len) == NULL ){ | |
| 51 fprintf(stderr, "Could not open test\&.wav: %s | |
| 52 ", SDL_GetError()); | |
| 53 SDL_CloseAudio(); | |
| 54 free(obtained); | |
| 55 exit(-1); | |
| 56 } | |
| 57 | |
| 58 /* Build AudioCVT */ | |
| 59 ret = SDL_BuildAudioCVT(&wav_cvt, | |
| 60 wav_spec\&.format, wav_spec\&.channels, wav_spec\&.freq, | |
| 61 obtained->format, obtained->channels, obtained->freq); | |
| 62 | |
| 63 /* Check that the convert was built */ | |
| 64 if(ret==-1){ | |
| 65 fprintf(stderr, "Couldn\&'t build converter! | |
| 66 "); | |
| 67 SDL_CloseAudio(); | |
| 68 free(obtained); | |
| 69 SDL_FreeWAV(wav_buf); | |
| 70 } | |
| 71 | |
| 72 /* Setup for conversion */ | |
| 73 wav_cvt\&.buf=(Uint8 *)malloc(wav_len*wav_cvt\&.len_mult); | |
| 74 wav_cvt\&.len=wav_len; | |
| 75 memcpy(wav_cvt\&.buf, wav_buf, wav_len); | |
| 76 | |
| 77 /* We can delete to original WAV data now */ | |
| 78 SDL_FreeWAV(wav_buf); | |
| 79 | |
| 80 /* And now we\&'re ready to convert */ | |
| 81 SDL_ConvertAudio(&wav_cvt); | |
| 82 | |
| 83 /* do whatever */ | |
| 84 \&. | |
| 85 \&. | |
| 86 \&. | |
| 87 \&. | |
| 88 | |
| 89 \fR | |
| 90 .fi | |
| 91 .PP | |
| 92 .SH "SEE ALSO" | |
| 93 .PP | |
| 94 \fI\fBSDL_BuildAudioCVT\fP\fR, \fI\fBSDL_AudioCVT\fP\fR | |
|
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
95 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58 |