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;
111 if( SDL_Init(SDL_INIT_AUDIO | SDL_INIT_NOPARACHUTE) != 0 )
113 intf_DbgMsg( "aout: SDL_Init failed (%s)", SDL_GetError() );
117 desired.freq = 11025; /* frequency */
118 desired.format = AUDIO_U8; /* unsigned 8 bits */
119 desired.channels = 2; /* mono */
120 desired.callback = NULL; /* no callback function yet */
121 desired.userdata = NULL; /* null parm for callback */
122 desired.samples = 4096;
124 /* If we were unable to open the device, there is no way we can use
125 * the plugin. Return a score of 0. */
126 if( SDL_OpenAudio( &desired, &obtained ) < 0 )
128 intf_DbgMsg( "aout: SDL_OpenAudio failed (%s)", SDL_GetError() );
132 /* Otherwise, there are good chances we can use this plugin, return 100. */
135 if( TestMethod( AOUT_METHOD_VAR, "sdl" ) )
143 /*****************************************************************************
144 * aout_Open: open the audio device
145 *****************************************************************************
146 * This function opens the dsp as a usual non-blocking write-only file, and
147 * modifies the p_aout->i_fd with the file's descriptor.
148 *****************************************************************************/
149 static int aout_Open( aout_thread_t *p_aout )
151 SDL_AudioSpec desired;
152 int i_channels = p_aout->b_stereo ? 2 : 1;
154 /* Allocate structure */
155 p_aout->p_sys = malloc( sizeof( aout_sys_t ) );
157 if( p_aout->p_sys == NULL )
159 intf_ErrMsg( "aout error: %s", strerror(ENOMEM) );
163 p_aout->p_sys->i_audio_end = 0;
164 p_aout->p_sys->audio_buf = malloc( OVERFLOWLIMIT );
166 /* Initialize some variables */
167 p_aout->psz_device = 0;
168 p_aout->i_format = AOUT_FORMAT_DEFAULT;
169 p_aout->i_channels = 1 + main_GetIntVariable( AOUT_STEREO_VAR,
170 AOUT_STEREO_DEFAULT );
171 p_aout->l_rate = main_GetIntVariable( AOUT_RATE_VAR,
174 desired.freq = p_aout->l_rate;
176 /* TODO: write conversion beetween AOUT_FORMAT_DEFAULT
177 * AND AUDIO* from SDL. */
178 desired.format = AUDIO_S16LSB; /* stereo 16 bits */
179 desired.channels = i_channels;
180 desired.callback = aout_SDLCallback;
181 desired.userdata = p_aout->p_sys;
182 desired.samples = 1024;
184 /* Open the sound device
185 * we just ask the SDL to wrap at the good frequency if the one we
186 * ask for is unavailable. This is done by setting the second parar
189 if( SDL_OpenAudio( &desired, NULL ) < 0 )
191 intf_ErrMsg( "aout error: SDL_OpenAudio failed (%s)", SDL_GetError() );
195 p_aout->p_sys->b_active = 1;
201 /*****************************************************************************
202 * aout_SetFormat: reset the audio device and sets its format
203 *****************************************************************************
204 * This functions resets the audio device, tries to initialize the output
205 * format with the value contained in the dsp structure, and if this value
206 * could not be set, the default value returned by ioctl is set. It then
207 * does the same for the stereo mode, and for the output rate.
208 *****************************************************************************/
209 static int aout_SetFormat( aout_thread_t *p_aout )
211 /* TODO: finish and clean this */
212 SDL_AudioSpec desired;
213 int i_stereo = p_aout->b_stereo ? 2 : 1;
215 /*i_format = p_aout->i_format;*/
216 desired.freq = p_aout->l_rate; /* Set the output rate */
217 desired.format = AUDIO_S16LSB; /* stereo 16 bits */
218 desired.channels = i_stereo;
219 desired.callback = aout_SDLCallback;
220 desired.userdata = p_aout->p_sys;
221 desired.samples = 2048;
223 /* Open the sound device */
227 if( SDL_OpenAudio( &desired, NULL ) < 0 )
229 p_aout->p_sys->b_active = 0;
233 p_aout->p_sys->b_active = 1;
239 /*****************************************************************************
240 * aout_GetBufInfo: buffer status query
241 *****************************************************************************
242 * returns the number of bytes in the audio buffer compared to the size of
244 *****************************************************************************/
245 static long aout_GetBufInfo( aout_thread_t *p_aout, long l_buffer_limit )
247 if(l_buffer_limit > p_aout->p_sys->i_audio_end)
249 /* returning 0 here juste gives awful sound in the speakers :/ */
250 return( l_buffer_limit );
252 return( p_aout->p_sys->i_audio_end - l_buffer_limit);
255 /*****************************************************************************
256 * aout_Play: play a sound samples buffer
257 *****************************************************************************
258 * This function writes a buffer of i_length bytes in the dsp
259 *****************************************************************************/
260 static void aout_Play( aout_thread_t *p_aout, byte_t *buffer, int i_size )
262 byte_t * audio_buf = p_aout->p_sys->audio_buf;
264 SDL_LockAudio(); /* Stop callbacking */
266 p_aout->p_sys->audio_buf = realloc( audio_buf,
267 p_aout->p_sys->i_audio_end + i_size);
268 memcpy( p_aout->p_sys->audio_buf + p_aout->p_sys->i_audio_end,
271 p_aout->p_sys->i_audio_end += i_size;
273 SDL_UnlockAudio(); /* go on callbacking */
276 /*****************************************************************************
277 * aout_Close: close the audio device
278 *****************************************************************************/
279 static void aout_Close( aout_thread_t *p_aout )
281 if( p_aout->p_sys->b_active )
283 SDL_PauseAudio( 1 ); /* pause audio */
285 if( p_aout->p_sys->audio_buf != NULL ) /* do we have a buffer now ? */
287 free( p_aout->p_sys->audio_buf );
293 free( p_aout->p_sys ); /* Close the Output. */
296 /*****************************************************************************
297 * aout_SDLCallback: what to do once SDL has played sound samples
298 *****************************************************************************/
299 static void aout_SDLCallback( void *userdata, byte_t *stream, int len )
301 struct aout_sys_s * p_sys = userdata;
303 if( p_sys->i_audio_end > OVERFLOWLIMIT )
305 intf_ErrMsg( "aout error: aout_SDLCallback overflowed" );
307 free( p_sys->audio_buf );
308 p_sys->audio_buf = NULL;
310 p_sys->i_audio_end = 0;
311 /* we've gone to slow, increase output freq */
314 /* if we are not in underrun */
315 if( p_sys->i_audio_end > len )
317 p_sys->i_audio_end -= len;
318 memcpy( stream, p_sys->audio_buf, len );
319 memmove( p_sys->audio_buf, p_sys->audio_buf + len, p_sys->i_audio_end );