1 /*****************************************************************************
2 * aout_sdl.c : audio sdl functions library
3 *****************************************************************************
4 * Copyright (C) 1999-2001 VideoLAN
5 * $Id: aout_sdl.c,v 1.22 2001/12/30 07:09:56 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 /*****************************************************************************
28 *****************************************************************************/
29 #include <errno.h> /* ENOMEM */
30 #include <fcntl.h> /* open(), O_WRONLY */
31 #include <string.h> /* strerror() */
32 #include <unistd.h> /* write(), close() */
33 #include <stdio.h> /* "intf_msg.h" */
34 #include <stdlib.h> /* calloc(), malloc(), free() */
36 #include <videolan/vlc.h>
38 #include SDL_INCLUDE_FILE
40 #include "audio_output.h" /* aout_thread_t */
42 /*****************************************************************************
43 * aout_sys_t: dsp audio output method descriptor
44 *****************************************************************************
45 * This structure is part of the audio output thread descriptor.
46 * It describes the dsp specific properties of an audio device.
47 *****************************************************************************/
49 /* the overflow limit is used to prevent the fifo from growing too big */
50 #define OVERFLOWLIMIT 100000
52 typedef struct aout_sys_s
61 /*****************************************************************************
63 *****************************************************************************/
64 static int aout_Probe ( probedata_t *p_data );
65 static int aout_Open ( aout_thread_t *p_aout );
66 static int aout_SetFormat ( aout_thread_t *p_aout );
67 static long aout_GetBufInfo ( aout_thread_t *p_aout, long l_buffer_info );
68 static void aout_Play ( aout_thread_t *p_aout,
69 byte_t *buffer, int i_size );
70 static void aout_Close ( aout_thread_t *p_aout );
72 static void aout_SDLCallback ( void *userdata, Uint8 *stream, int len );
74 /*****************************************************************************
75 * Functions exported as capabilities. They are declared as static so that
76 * we don't pollute the namespace too much.
77 *****************************************************************************/
78 void _M( aout_getfunctions )( function_list_t * p_function_list )
80 p_function_list->pf_probe = aout_Probe;
81 p_function_list->functions.aout.pf_open = aout_Open;
82 p_function_list->functions.aout.pf_setformat = aout_SetFormat;
83 p_function_list->functions.aout.pf_getbufinfo = aout_GetBufInfo;
84 p_function_list->functions.aout.pf_play = aout_Play;
85 p_function_list->functions.aout.pf_close = aout_Close;
88 /*****************************************************************************
89 * aout_Probe: probe the audio device and return a score
90 *****************************************************************************
91 * This function tries to initialize SDL audio and returns a score to the
92 * plugin manager so that it can select the best plugin.
93 *****************************************************************************/
94 static int aout_Probe( probedata_t *p_data )
97 SDL_AudioSpec desired, obtained;
100 if( SDL_WasInit( SDL_INIT_AUDIO ) != 0 )
107 if( SDL_Init(SDL_INIT_AUDIO | SDL_INIT_NOPARACHUTE) != 0 )
109 intf_DbgMsg( "aout: SDL_Init failed (%s)", SDL_GetError() );
113 desired.freq = 11025; /* frequency */
114 desired.format = AUDIO_U8; /* unsigned 8 bits */
115 desired.channels = 2; /* mono */
116 desired.callback = aout_SDLCallback; /* callback function mandatory */
117 desired.userdata = NULL; /* null parm for callback */
118 desired.samples = 4096;
120 /* If we were unable to open the device, there is no way we can use
121 * the plugin. Return a score of 0. */
122 if( SDL_OpenAudio( &desired, &obtained ) < 0 )
124 intf_DbgMsg( "aout: SDL_OpenAudio failed (%s)", SDL_GetError() );
128 /* Otherwise, there are good chances we can use this plugin, return 100. */
129 intf_DbgMsg( "aout: SDL_OpenAudio successfully run" );
136 /*****************************************************************************
137 * aout_Open: open the audio device
138 *****************************************************************************
139 * This function opens the dsp as a usual non-blocking write-only file, and
140 * modifies the p_aout->i_fd with the file's descriptor.
141 *****************************************************************************/
142 static int aout_Open( aout_thread_t *p_aout )
144 SDL_AudioSpec desired;
145 int i_channels = p_aout->b_stereo ? 2 : 1;
147 /* Allocate structure */
148 p_aout->p_sys = malloc( sizeof( aout_sys_t ) );
150 if( p_aout->p_sys == NULL )
152 intf_ErrMsg( "aout error: %s", strerror(ENOMEM) );
156 /* Initialize library */
157 if( SDL_Init( SDL_INIT_AUDIO
159 /* Win32 SDL implementation doesn't support SDL_INIT_EVENTTHREAD yet*/
160 | SDL_INIT_EVENTTHREAD
163 /* In debug mode you may want vlc to dump a core instead of staying
165 | SDL_INIT_NOPARACHUTE
169 intf_ErrMsg( "aout error: can't initialize SDL (%s)", SDL_GetError() );
170 free( p_aout->p_sys );
174 p_aout->p_sys->i_audio_end = 0;
175 p_aout->p_sys->audio_buf = malloc( OVERFLOWLIMIT );
177 /* Initialize some variables */
178 p_aout->psz_device = 0;
179 p_aout->i_format = AOUT_FORMAT_DEFAULT;
180 p_aout->i_channels = 1 + main_GetIntVariable( AOUT_STEREO_VAR,
181 AOUT_STEREO_DEFAULT );
182 p_aout->l_rate = main_GetIntVariable( AOUT_RATE_VAR,
185 desired.freq = p_aout->l_rate;
187 /* TODO: write conversion beetween AOUT_FORMAT_DEFAULT
188 * AND AUDIO* from SDL. */
189 desired.format = AUDIO_S16LSB; /* stereo 16 bits */
190 desired.channels = i_channels;
191 desired.callback = aout_SDLCallback;
192 desired.userdata = p_aout->p_sys;
193 desired.samples = 1024;
195 /* Open the sound device
196 * we just ask the SDL to wrap at the good frequency if the one we
197 * ask for is unavailable. This is done by setting the second parar
200 if( SDL_OpenAudio( &desired, NULL ) < 0 )
202 intf_ErrMsg( "aout error: SDL_OpenAudio failed (%s)", SDL_GetError() );
203 SDL_QuitSubSystem( SDL_INIT_AUDIO );
204 free( p_aout->p_sys );
208 p_aout->p_sys->b_active = 1;
214 /*****************************************************************************
215 * aout_SetFormat: reset the audio device and sets its format
216 *****************************************************************************
217 * This functions resets the audio device, tries to initialize the output
218 * format with the value contained in the dsp structure, and if this value
219 * could not be set, the default value returned by ioctl is set. It then
220 * does the same for the stereo mode, and for the output rate.
221 *****************************************************************************/
222 static int aout_SetFormat( aout_thread_t *p_aout )
224 /* TODO: finish and clean this */
225 SDL_AudioSpec desired;
226 int i_stereo = p_aout->b_stereo ? 2 : 1;
228 /*i_format = p_aout->i_format;*/
229 desired.freq = p_aout->l_rate; /* Set the output rate */
230 desired.format = AUDIO_S16LSB; /* stereo 16 bits */
231 desired.channels = i_stereo;
232 desired.callback = aout_SDLCallback;
233 desired.userdata = p_aout->p_sys;
234 desired.samples = 2048;
236 /* Open the sound device */
240 if( SDL_OpenAudio( &desired, NULL ) < 0 )
242 p_aout->p_sys->b_active = 0;
246 p_aout->p_sys->b_active = 1;
249 p_aout->i_latency = 0;
254 /*****************************************************************************
255 * aout_GetBufInfo: buffer status query
256 *****************************************************************************
257 * returns the number of bytes in the audio buffer compared to the size of
259 *****************************************************************************/
260 static long aout_GetBufInfo( aout_thread_t *p_aout, long l_buffer_limit )
262 if(l_buffer_limit > p_aout->p_sys->i_audio_end)
264 /* returning 0 here juste gives awful sound in the speakers :/ */
265 return( l_buffer_limit );
267 return( p_aout->p_sys->i_audio_end - l_buffer_limit);
270 /*****************************************************************************
271 * aout_Play: play a sound samples buffer
272 *****************************************************************************
273 * This function writes a buffer of i_length bytes in the dsp
274 *****************************************************************************/
275 static void aout_Play( aout_thread_t *p_aout, byte_t *buffer, int i_size )
277 byte_t * audio_buf = p_aout->p_sys->audio_buf;
279 SDL_LockAudio(); /* Stop callbacking */
281 p_aout->p_sys->audio_buf = realloc( audio_buf,
282 p_aout->p_sys->i_audio_end + i_size);
283 memcpy( p_aout->p_sys->audio_buf + p_aout->p_sys->i_audio_end,
286 p_aout->p_sys->i_audio_end += i_size;
288 SDL_UnlockAudio(); /* go on callbacking */
291 /*****************************************************************************
292 * aout_Close: close the audio device
293 *****************************************************************************/
294 static void aout_Close( aout_thread_t *p_aout )
296 if( p_aout->p_sys->b_active )
298 SDL_PauseAudio( 1 ); /* pause audio */
300 if( p_aout->p_sys->audio_buf != NULL ) /* do we have a buffer now ? */
302 free( p_aout->p_sys->audio_buf );
308 SDL_QuitSubSystem( SDL_INIT_AUDIO );
310 free( p_aout->p_sys ); /* Close the Output. */
313 /*****************************************************************************
314 * aout_SDLCallback: what to do once SDL has played sound samples
315 *****************************************************************************/
316 static void aout_SDLCallback( void *userdata, byte_t *stream, int len )
318 struct aout_sys_s * p_sys = userdata;
320 if( p_sys->i_audio_end > OVERFLOWLIMIT )
322 intf_ErrMsg( "aout error: aout_SDLCallback overflowed" );
324 free( p_sys->audio_buf );
325 p_sys->audio_buf = NULL;
327 p_sys->i_audio_end = 0;
328 /* we've gone to slow, increase output freq */
331 /* if we are not in underrun */
332 if( p_sys->i_audio_end > len )
334 p_sys->i_audio_end -= len;
335 memcpy( stream, p_sys->audio_buf, len );
336 memmove( p_sys->audio_buf, p_sys->audio_buf + len, p_sys->i_audio_end );