1 /*****************************************************************************
2 * aout_sdl.c : audio sdl functions library
3 *****************************************************************************
4 * Copyright (C) 1999, 2000 VideoLAN
6 * Authors: Michel Kaempf <maxx@via.ecp.fr>
7 * Samuel Hocevar <sam@zoy.org>
8 * Pierre Baillet <oct@zoy.org>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
23 *****************************************************************************/
25 /*****************************************************************************
27 *****************************************************************************/
30 #include <errno.h> /* ENOMEM */
31 #include <fcntl.h> /* open(), O_WRONLY */
32 #include <sys/ioctl.h> /* ioctl() */
33 #include <string.h> /* strerror() */
34 #include <unistd.h> /* write(), close() */
35 #include <stdio.h> /* "intf_msg.h" */
36 #include <stdlib.h> /* calloc(), malloc(), free() */
38 #include <SDL/SDL.h> /* SDL base include */
41 #include "common.h" /* boolean_t, byte_t */
46 #include "audio_output.h" /* aout_thread_t */
48 #include "intf_msg.h" /* intf_DbgMsg(), intf_ErrMsg() */
53 /*****************************************************************************
54 * aout_sys_t: dsp audio output method descriptor
55 *****************************************************************************
56 * This structure is part of the audio output thread descriptor.
57 * It describes the dsp specific properties of an audio device.
58 *****************************************************************************/
60 /* the overflow limit is used to prevent the fifo from growing too big */
61 #define OVERFLOWLIMIT 100000
63 typedef struct aout_sys_s
72 /*****************************************************************************
74 *****************************************************************************/
75 static int aout_Probe ( probedata_t *p_data );
76 static int aout_Open ( aout_thread_t *p_aout );
77 static int aout_SetFormat ( aout_thread_t *p_aout );
78 static long aout_GetBufInfo ( aout_thread_t *p_aout, long l_buffer_info );
79 static void aout_Play ( aout_thread_t *p_aout,
80 byte_t *buffer, int i_size );
81 static void aout_Close ( aout_thread_t *p_aout );
83 static void aout_SDLCallback ( void *userdata, Uint8 *stream, int len );
85 /*****************************************************************************
86 * Functions exported as capabilities. They are declared as static so that
87 * we don't pollute the namespace too much.
88 *****************************************************************************/
89 void aout_getfunctions( function_list_t * p_function_list )
91 p_function_list->pf_probe = aout_Probe;
92 p_function_list->functions.aout.pf_open = aout_Open;
93 p_function_list->functions.aout.pf_setformat = aout_SetFormat;
94 p_function_list->functions.aout.pf_getbufinfo = aout_GetBufInfo;
95 p_function_list->functions.aout.pf_play = aout_Play;
96 p_function_list->functions.aout.pf_close = aout_Close;
99 /*****************************************************************************
100 * aout_Probe: probe the audio device and return a score
101 *****************************************************************************
102 * This function tries to initialize SDL audio and returns a score to the
103 * plugin manager so that it can select the best plugin.
104 *****************************************************************************/
105 static int aout_Probe( probedata_t *p_data )
107 SDL_AudioSpec desired, obtained;
110 if( SDL_Init(SDL_INIT_AUDIO) != 0 )
112 intf_DbgMsg( "aout: SDL_Init failed (%s)", SDL_GetError() );
116 desired.freq = 11025; /* frequency */
117 desired.format = AUDIO_U8; /* unsigned 8 bits */
118 desired.channels = 2; /* mono */
119 desired.callback = aout_SDLCallback; /* no callback function yet */
120 desired.userdata = NULL; /* null parm for callback */
121 desired.samples = 4096;
123 /* If we were unable to open the device, there is no way we can use
124 * the plugin. Return a score of 0. */
125 if( SDL_OpenAudio( &desired, &obtained ) < 0 )
127 intf_DbgMsg( "aout: SDL_OpenAudio failed (%s)", SDL_GetError() );
131 /* Otherwise, there are good chances we can use this plugin, return 100. */
134 if( TestMethod( AOUT_METHOD_VAR, "sdl" ) )
142 /*****************************************************************************
143 * aout_Open: open the audio device
144 *****************************************************************************
145 * This function opens the dsp as a usual non-blocking write-only file, and
146 * modifies the p_aout->i_fd with the file's descriptor.
147 *****************************************************************************/
148 static int aout_Open( aout_thread_t *p_aout )
150 SDL_AudioSpec desired;
151 int i_channels = p_aout->b_stereo ? 2 : 1;
153 /* Allocate structure */
154 p_aout->p_sys = malloc( sizeof( aout_sys_t ) );
156 if( p_aout->p_sys == NULL )
158 intf_ErrMsg( "aout error: %s", strerror(ENOMEM) );
162 p_aout->p_sys->i_audio_end = 0;
163 p_aout->p_sys->audio_buf = malloc( OVERFLOWLIMIT );
165 /* Initialize some variables */
166 p_aout->psz_device = 0;
167 p_aout->i_format = AOUT_FORMAT_DEFAULT;
168 p_aout->i_channels = 1 + main_GetIntVariable( AOUT_STEREO_VAR,
169 AOUT_STEREO_DEFAULT );
170 p_aout->l_rate = main_GetIntVariable( AOUT_RATE_VAR,
173 desired.freq = p_aout->l_rate;
175 /* TODO: write conversion beetween AOUT_FORMAT_DEFAULT
176 * AND AUDIO* from SDL. */
177 desired.format = AUDIO_S16LSB; /* stereo 16 bits */
178 desired.channels = i_channels;
179 desired.callback = aout_SDLCallback;
180 desired.userdata = p_aout->p_sys;
181 desired.samples = 1024;
183 /* Open the sound device
184 * we just ask the SDL to wrap at the good frequency if the one we
185 * ask for is unavailable. This is done by setting the second parar
188 if( SDL_OpenAudio( &desired, NULL ) < 0 )
190 intf_ErrMsg( "aout error: SDL_OpenAudio failed (%s)", SDL_GetError() );
194 p_aout->p_sys->b_active = 1;
200 /*****************************************************************************
201 * aout_SetFormat: reset the audio device and sets its format
202 *****************************************************************************
203 * This functions resets the audio device, tries to initialize the output
204 * format with the value contained in the dsp structure, and if this value
205 * could not be set, the default value returned by ioctl is set. It then
206 * does the same for the stereo mode, and for the output rate.
207 *****************************************************************************/
208 static int aout_SetFormat( aout_thread_t *p_aout )
210 /* TODO: finish and clean this */
211 SDL_AudioSpec desired;
212 int i_stereo = p_aout->b_stereo ? 2 : 1;
214 /*i_format = p_aout->i_format;*/
215 desired.freq = p_aout->l_rate; /* Set the output rate */
216 desired.format = AUDIO_S16LSB; /* stereo 16 bits */
217 desired.channels = i_stereo;
218 desired.callback = aout_SDLCallback;
219 desired.userdata = p_aout->p_sys;
220 desired.samples = 2048;
222 /* Open the sound device */
226 if( SDL_OpenAudio( &desired, NULL ) < 0 )
228 p_aout->p_sys->b_active = 0;
232 p_aout->p_sys->b_active = 1;
238 /*****************************************************************************
239 * aout_GetBufInfo: buffer status query
240 *****************************************************************************
241 * returns the number of bytes in the audio buffer compared to the size of
243 *****************************************************************************/
244 static long aout_GetBufInfo( aout_thread_t *p_aout, long l_buffer_limit )
246 if(l_buffer_limit > p_aout->p_sys->i_audio_end)
248 /* returning 0 here juste gives awful sound in the speakers :/ */
249 return( l_buffer_limit );
251 return( p_aout->p_sys->i_audio_end - l_buffer_limit);
254 /*****************************************************************************
255 * aout_Play: play a sound samples buffer
256 *****************************************************************************
257 * This function writes a buffer of i_length bytes in the dsp
258 *****************************************************************************/
259 static void aout_Play( aout_thread_t *p_aout, byte_t *buffer, int i_size )
261 byte_t * audio_buf = p_aout->p_sys->audio_buf;
263 SDL_LockAudio(); /* Stop callbacking */
265 p_aout->p_sys->audio_buf = realloc( audio_buf,
266 p_aout->p_sys->i_audio_end + i_size);
267 memcpy( p_aout->p_sys->audio_buf + p_aout->p_sys->i_audio_end,
270 p_aout->p_sys->i_audio_end += i_size;
272 SDL_UnlockAudio(); /* go on callbacking */
275 /*****************************************************************************
276 * aout_Close: close the audio device
277 *****************************************************************************/
278 static void aout_Close( aout_thread_t *p_aout )
280 if( p_aout->p_sys->b_active )
282 SDL_PauseAudio( 1 ); /* pause audio */
284 if( p_aout->p_sys->audio_buf != NULL ) /* do we have a buffer now ? */
286 free( p_aout->p_sys->audio_buf );
292 free( p_aout->p_sys ); /* Close the Output. */
295 /*****************************************************************************
296 * aout_SDLCallback: what to do once SDL has played sound samples
297 *****************************************************************************/
298 static void aout_SDLCallback( void *userdata, byte_t *stream, int len )
300 struct aout_sys_s * p_sys = userdata;
302 if( p_sys->i_audio_end > OVERFLOWLIMIT )
304 intf_ErrMsg( "aout error: aout_SDLCallback overflowed" );
306 free( p_sys->audio_buf );
307 p_sys->audio_buf = NULL;
309 p_sys->i_audio_end = 0;
310 /* we've gone to slow, increase output freq */
313 /* if we are not in underrun */
314 if( p_sys->i_audio_end > len )
316 p_sys->i_audio_end -= len;
317 memcpy( stream, p_sys->audio_buf, len );
318 memmove( p_sys->audio_buf, p_sys->audio_buf + len, p_sys->i_audio_end );