annotate docs/man3/SDL_ConvertAudio.3 @ 4223:63fd67e17705 SDL-1.2

Fixed bug #727 Lorenzo Desole 2009-04-19 07:36:10 PDT I am one of the developers of a multimedia application (My Media System MMS), which uses SDL. MMS is normally running in fullscreen mode but it switches it off before launching external applications (mplayer, xine, etc.). The problem with fullscreen is that when the latter is switched off either via SDL_WM_ToggleFullScreen() or SDL_SetVideoMode(), SDL compares the current screen sizes with the ones saved when the video system was initted, and if they don't match, it calls XF86VidModeSwitchToMode() to switch to the old modeline. This makes it impossible for external programs and for MMS itself to use RandR to change the screen size, because next time fullscreen mode is turned off, it bombs out with the following error: X Error of failed request: BadValue (integer parameter out of range for operation) Major opcode of failed request: 136 (XFree86-VidModeExtension) Minor opcode of failed request: 10 (XF86VidModeSwitchToMode) [...] Obviously this happens only if the new screen resolution is smaller than the original one and XF86VidModeSwitchToMode() can't succeed. I couldn't find any way to inform SDL that the screen resolution it uses as reference is no longer valid. This can be fixed by adding "save_mode(this)" to ./src/video/x11/SDL_x11modes.c, API X11_EnterFullScreen(_THIS), like this: int X11_EnterFullScreen(_THIS) { int okay; + save_mode(this); I can't rule out possible side effects, but I don't see any. While I admit this is a minor issue for the general users, it is a major showstopper for our program where the ability to change screen resolution and refresh rate according to the movie being played, is very important. Thanks in advance.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 21 Sep 2009 11:14:36 +0000
parents 4e3b250c950e
children 1238da4a7112
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
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
2 .SH "NAME"
4107
4e3b250c950e Erik Heckers fixed bug #493
Sam Lantinga <slouken@libsdl.org>
parents: 181
diff changeset
3 SDL_ConvertAudio \- Convert audio data to a desired audio format\&.
0
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
4 .SH "SYNOPSIS"
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
5 .PP
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
6 \fB#include "SDL\&.h"
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
7 .sp
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
8 \fBint \fBSDL_ConvertAudio\fP\fR(\fBSDL_AudioCVT *cvt\fR);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
9 .SH "DESCRIPTION"
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
10 .PP
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
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\&.
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
12 .PP
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
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\&.
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
14 .PP
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
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\&.
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
16 .SH "EXAMPLES"
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
17 .PP
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
18 .nf
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
19 \f(CW/* Converting some WAV data to hardware format */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
20 void my_audio_callback(void *userdata, Uint8 *stream, int len);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
21
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
22 SDL_AudioSpec *desired, *obtained;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
23 SDL_AudioSpec wav_spec;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
24 SDL_AudioCVT wav_cvt;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
25 Uint32 wav_len;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
26 Uint8 *wav_buf;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
27 int ret;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
28
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
29 /* Allocated audio specs */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
30 desired=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec));
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
31 obtained=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec));
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
32
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
33 /* Set desired format */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
34 desired->freq=22050;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
35 desired->format=AUDIO_S16LSB;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
36 desired->samples=8192;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
37 desired->callback=my_audio_callback;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
38 desired->userdata=NULL;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
39
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
40 /* Open the audio device */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
41 if ( SDL_OpenAudio(desired, obtained) < 0 ){
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
42 fprintf(stderr, "Couldn\&'t open audio: %s
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
43 ", SDL_GetError());
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
44 exit(-1);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
45 }
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
46
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
47 free(desired);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
48
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
49 /* Load the test\&.wav */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
50 if( SDL_LoadWAV("test\&.wav", &wav_spec, &wav_buf, &wav_len) == NULL ){
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
51 fprintf(stderr, "Could not open test\&.wav: %s
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
52 ", SDL_GetError());
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
53 SDL_CloseAudio();
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
54 free(obtained);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
55 exit(-1);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
56 }
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
57
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
58 /* Build AudioCVT */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
59 ret = SDL_BuildAudioCVT(&wav_cvt,
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
60 wav_spec\&.format, wav_spec\&.channels, wav_spec\&.freq,
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
61 obtained->format, obtained->channels, obtained->freq);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
62
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
63 /* Check that the convert was built */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
64 if(ret==-1){
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
65 fprintf(stderr, "Couldn\&'t build converter!
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
66 ");
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
67 SDL_CloseAudio();
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
68 free(obtained);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
69 SDL_FreeWAV(wav_buf);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
70 }
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
71
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
72 /* Setup for conversion */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
73 wav_cvt\&.buf=(Uint8 *)malloc(wav_len*wav_cvt\&.len_mult);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
74 wav_cvt\&.len=wav_len;
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
75 memcpy(wav_cvt\&.buf, wav_buf, wav_len);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
76
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
77 /* We can delete to original WAV data now */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
78 SDL_FreeWAV(wav_buf);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
79
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
80 /* And now we\&'re ready to convert */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
81 SDL_ConvertAudio(&wav_cvt);
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
82
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
83 /* do whatever */
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
84 \&.
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
85 \&.
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
86 \&.
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
87 \&.
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
88
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
89 \fR
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
90 .fi
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
91 .PP
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
92 .SH "SEE ALSO"
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
93 .PP
74212992fb08 Initial revision
Sam Lantinga <slouken@lokigames.com>
parents:
diff changeset
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