1 /*****************************************************************************
2 * aout_sdl.c : audio sdl functions library
3 *****************************************************************************
4 * Copyright (C) 1999, 2000 VideoLAN
5 * $Id: aout_sdl.c,v 1.12 2001/04/28 03:36:25 sam Exp $
7 * Authors: Michel Kaempf <maxx@via.ecp.fr>
8 * Samuel Hocevar <sam@zoy.org>
9 * Pierre Baillet <oct@zoy.org>
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
24 *****************************************************************************/
26 #define MODULE_NAME sdl
27 #include "modules_inner.h"
29 /*****************************************************************************
31 *****************************************************************************/
34 #include <errno.h> /* ENOMEM */
35 #include <fcntl.h> /* open(), O_WRONLY */
36 #include <string.h> /* strerror() */
37 #include <unistd.h> /* write(), close() */
38 #include <stdio.h> /* "intf_msg.h" */
39 #include <stdlib.h> /* calloc(), malloc(), free() */
41 #include <SDL/SDL.h> /* SDL base include */
44 #include "common.h" /* boolean_t, byte_t */
49 #include "audio_output.h" /* aout_thread_t */
51 #include "intf_msg.h" /* intf_DbgMsg(), intf_ErrMsg() */
56 /*****************************************************************************
57 * aout_sys_t: dsp audio output method descriptor
58 *****************************************************************************
59 * This structure is part of the audio output thread descriptor.
60 * It describes the dsp specific properties of an audio device.
61 *****************************************************************************/
63 /* the overflow limit is used to prevent the fifo from growing too big */
64 #define OVERFLOWLIMIT 100000
66 typedef struct aout_sys_s
75 /*****************************************************************************
77 *****************************************************************************/
78 static int aout_Probe ( probedata_t *p_data );
79 static int aout_Open ( aout_thread_t *p_aout );
80 static int aout_SetFormat ( aout_thread_t *p_aout );
81 static long aout_GetBufInfo ( aout_thread_t *p_aout, long l_buffer_info );
82 static void aout_Play ( aout_thread_t *p_aout,
83 byte_t *buffer, int i_size );
84 static void aout_Close ( aout_thread_t *p_aout );
86 static void aout_SDLCallback ( void *userdata, Uint8 *stream, int len );
88 /*****************************************************************************
89 * Functions exported as capabilities. They are declared as static so that
90 * we don't pollute the namespace too much.
91 *****************************************************************************/
92 void _M( aout_getfunctions )( function_list_t * p_function_list )
94 p_function_list->pf_probe = aout_Probe;
95 p_function_list->functions.aout.pf_open = aout_Open;
96 p_function_list->functions.aout.pf_setformat = aout_SetFormat;
97 p_function_list->functions.aout.pf_getbufinfo = aout_GetBufInfo;
98 p_function_list->functions.aout.pf_play = aout_Play;
99 p_function_list->functions.aout.pf_close = aout_Close;
102 /*****************************************************************************
103 * aout_Probe: probe the audio device and return a score
104 *****************************************************************************
105 * This function tries to initialize SDL audio and returns a score to the
106 * plugin manager so that it can select the best plugin.
107 *****************************************************************************/
108 static int aout_Probe( probedata_t *p_data )
110 SDL_AudioSpec desired, obtained;
113 if( SDL_Init(SDL_INIT_AUDIO | SDL_INIT_NOPARACHUTE) != 0 )
115 intf_DbgMsg( "aout: SDL_Init failed (%s)", SDL_GetError() );
119 desired.freq = 11025; /* frequency */
120 desired.format = AUDIO_U8; /* unsigned 8 bits */
121 desired.channels = 2; /* mono */
122 desired.callback = aout_SDLCallback; /* callback function mandatory */
123 desired.userdata = NULL; /* null parm for callback */
124 desired.samples = 4096;
126 /* If we were unable to open the device, there is no way we can use
127 * the plugin. Return a score of 0. */
128 if( SDL_OpenAudio( &desired, &obtained ) < 0 )
130 intf_DbgMsg( "aout: SDL_OpenAudio failed (%s)", SDL_GetError() );
134 /* Otherwise, there are good chances we can use this plugin, return 100. */
135 intf_DbgMsg( "aout: SDL_OpenAudio successfully run" );
138 if( TestMethod( AOUT_METHOD_VAR, "sdl" ) )
146 /*****************************************************************************
147 * aout_Open: open the audio device
148 *****************************************************************************
149 * This function opens the dsp as a usual non-blocking write-only file, and
150 * modifies the p_aout->i_fd with the file's descriptor.
151 *****************************************************************************/
152 static int aout_Open( aout_thread_t *p_aout )
154 SDL_AudioSpec desired;
155 int i_channels = p_aout->b_stereo ? 2 : 1;
157 /* Allocate structure */
158 p_aout->p_sys = malloc( sizeof( aout_sys_t ) );
160 if( p_aout->p_sys == NULL )
162 intf_ErrMsg( "aout error: %s", strerror(ENOMEM) );
166 p_aout->p_sys->i_audio_end = 0;
167 p_aout->p_sys->audio_buf = malloc( OVERFLOWLIMIT );
169 /* Initialize some variables */
170 p_aout->psz_device = 0;
171 p_aout->i_format = AOUT_FORMAT_DEFAULT;
172 p_aout->i_channels = 1 + main_GetIntVariable( AOUT_STEREO_VAR,
173 AOUT_STEREO_DEFAULT );
174 p_aout->l_rate = main_GetIntVariable( AOUT_RATE_VAR,
177 desired.freq = p_aout->l_rate;
179 /* TODO: write conversion beetween AOUT_FORMAT_DEFAULT
180 * AND AUDIO* from SDL. */
181 desired.format = AUDIO_S16LSB; /* stereo 16 bits */
182 desired.channels = i_channels;
183 desired.callback = aout_SDLCallback;
184 desired.userdata = p_aout->p_sys;
185 desired.samples = 1024;
187 /* Open the sound device
188 * we just ask the SDL to wrap at the good frequency if the one we
189 * ask for is unavailable. This is done by setting the second parar
192 if( SDL_OpenAudio( &desired, NULL ) < 0 )
194 intf_ErrMsg( "aout error: SDL_OpenAudio failed (%s)", SDL_GetError() );
198 p_aout->p_sys->b_active = 1;
204 /*****************************************************************************
205 * aout_SetFormat: reset the audio device and sets its format
206 *****************************************************************************
207 * This functions resets the audio device, tries to initialize the output
208 * format with the value contained in the dsp structure, and if this value
209 * could not be set, the default value returned by ioctl is set. It then
210 * does the same for the stereo mode, and for the output rate.
211 *****************************************************************************/
212 static int aout_SetFormat( aout_thread_t *p_aout )
214 /* TODO: finish and clean this */
215 SDL_AudioSpec desired;
216 int i_stereo = p_aout->b_stereo ? 2 : 1;
218 /*i_format = p_aout->i_format;*/
219 desired.freq = p_aout->l_rate; /* Set the output rate */
220 desired.format = AUDIO_S16LSB; /* stereo 16 bits */
221 desired.channels = i_stereo;
222 desired.callback = aout_SDLCallback;
223 desired.userdata = p_aout->p_sys;
224 desired.samples = 2048;
226 /* Open the sound device */
230 if( SDL_OpenAudio( &desired, NULL ) < 0 )
232 p_aout->p_sys->b_active = 0;
236 p_aout->p_sys->b_active = 1;
242 /*****************************************************************************
243 * aout_GetBufInfo: buffer status query
244 *****************************************************************************
245 * returns the number of bytes in the audio buffer compared to the size of
247 *****************************************************************************/
248 static long aout_GetBufInfo( aout_thread_t *p_aout, long l_buffer_limit )
250 if(l_buffer_limit > p_aout->p_sys->i_audio_end)
252 /* returning 0 here juste gives awful sound in the speakers :/ */
253 return( l_buffer_limit );
255 return( p_aout->p_sys->i_audio_end - l_buffer_limit);
258 /*****************************************************************************
259 * aout_Play: play a sound samples buffer
260 *****************************************************************************
261 * This function writes a buffer of i_length bytes in the dsp
262 *****************************************************************************/
263 static void aout_Play( aout_thread_t *p_aout, byte_t *buffer, int i_size )
265 byte_t * audio_buf = p_aout->p_sys->audio_buf;
267 SDL_LockAudio(); /* Stop callbacking */
269 p_aout->p_sys->audio_buf = realloc( audio_buf,
270 p_aout->p_sys->i_audio_end + i_size);
271 memcpy( p_aout->p_sys->audio_buf + p_aout->p_sys->i_audio_end,
274 p_aout->p_sys->i_audio_end += i_size;
276 SDL_UnlockAudio(); /* go on callbacking */
279 /*****************************************************************************
280 * aout_Close: close the audio device
281 *****************************************************************************/
282 static void aout_Close( aout_thread_t *p_aout )
284 if( p_aout->p_sys->b_active )
286 SDL_PauseAudio( 1 ); /* pause audio */
288 if( p_aout->p_sys->audio_buf != NULL ) /* do we have a buffer now ? */
290 free( p_aout->p_sys->audio_buf );
296 free( p_aout->p_sys ); /* Close the Output. */
299 /*****************************************************************************
300 * aout_SDLCallback: what to do once SDL has played sound samples
301 *****************************************************************************/
302 static void aout_SDLCallback( void *userdata, byte_t *stream, int len )
304 struct aout_sys_s * p_sys = userdata;
306 if( p_sys->i_audio_end > OVERFLOWLIMIT )
308 intf_ErrMsg( "aout error: aout_SDLCallback overflowed" );
310 free( p_sys->audio_buf );
311 p_sys->audio_buf = NULL;
313 p_sys->i_audio_end = 0;
314 /* we've gone to slow, increase output freq */
317 /* if we are not in underrun */
318 if( p_sys->i_audio_end > len )
320 p_sys->i_audio_end -= len;
321 memcpy( stream, p_sys->audio_buf, len );
322 memmove( p_sys->audio_buf, p_sys->audio_buf + len, p_sys->i_audio_end );