1 /*****************************************************************************
2 * aout_sdl.c : audio sdl functions library
3 *****************************************************************************
4 * Copyright (C) 1999-2001 VideoLAN
5 * $Id: aout_sdl.c,v 1.25 2002/02/15 13:32:53 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_Open ( aout_thread_t *p_aout );
65 static int aout_SetFormat ( aout_thread_t *p_aout );
66 static long aout_GetBufInfo ( aout_thread_t *p_aout, long l_buffer_info );
67 static void aout_Play ( aout_thread_t *p_aout,
68 byte_t *buffer, int i_size );
69 static void aout_Close ( aout_thread_t *p_aout );
71 static void aout_SDLCallback ( void *userdata, Uint8 *stream, int len );
73 /*****************************************************************************
74 * Functions exported as capabilities. They are declared as static so that
75 * we don't pollute the namespace too much.
76 *****************************************************************************/
77 void _M( aout_getfunctions )( function_list_t * p_function_list )
79 p_function_list->functions.aout.pf_open = aout_Open;
80 p_function_list->functions.aout.pf_setformat = aout_SetFormat;
81 p_function_list->functions.aout.pf_getbufinfo = aout_GetBufInfo;
82 p_function_list->functions.aout.pf_play = aout_Play;
83 p_function_list->functions.aout.pf_close = aout_Close;
86 /*****************************************************************************
87 * aout_Open: open the audio device
88 *****************************************************************************
89 * This function opens the dsp as a usual non-blocking write-only file, and
90 * modifies the p_aout->i_fd with the file's descriptor.
91 *****************************************************************************/
92 static int aout_Open( aout_thread_t *p_aout )
94 SDL_AudioSpec desired;
95 int i_channels = p_aout->b_stereo ? 2 : 1;
97 if( SDL_WasInit( SDL_INIT_AUDIO ) != 0 )
102 /* Allocate structure */
103 p_aout->p_sys = malloc( sizeof( aout_sys_t ) );
105 if( p_aout->p_sys == NULL )
107 intf_ErrMsg( "aout error: %s", strerror(ENOMEM) );
111 /* Initialize library */
112 if( SDL_Init( SDL_INIT_AUDIO
114 /* Win32 SDL implementation doesn't support SDL_INIT_EVENTTHREAD yet*/
115 | SDL_INIT_EVENTTHREAD
118 /* In debug mode you may want vlc to dump a core instead of staying
120 | SDL_INIT_NOPARACHUTE
124 intf_ErrMsg( "aout error: can't initialize SDL (%s)", SDL_GetError() );
125 free( p_aout->p_sys );
129 p_aout->p_sys->i_audio_end = 0;
130 p_aout->p_sys->audio_buf = malloc( OVERFLOWLIMIT );
132 /* Initialize some variables */
133 p_aout->psz_device = 0;
134 desired.freq = p_aout->l_rate;
136 /* TODO: write conversion beetween AOUT_FORMAT_DEFAULT
137 * AND AUDIO* from SDL. */
138 desired.format = AUDIO_S16LSB; /* stereo 16 bits */
139 desired.channels = i_channels;
140 desired.callback = aout_SDLCallback;
141 desired.userdata = p_aout->p_sys;
142 desired.samples = 1024;
144 /* Open the sound device
145 * we just ask the SDL to wrap at the good frequency if the one we
146 * ask for is unavailable. This is done by setting the second parar
149 if( SDL_OpenAudio( &desired, NULL ) < 0 )
151 intf_ErrMsg( "aout error: SDL_OpenAudio failed (%s)", SDL_GetError() );
152 SDL_QuitSubSystem( SDL_INIT_AUDIO );
153 free( p_aout->p_sys );
157 p_aout->p_sys->b_active = 1;
163 /*****************************************************************************
164 * aout_SetFormat: reset the audio device and sets its format
165 *****************************************************************************
166 * This functions resets the audio device, tries to initialize the output
167 * format with the value contained in the dsp structure, and if this value
168 * could not be set, the default value returned by ioctl is set. It then
169 * does the same for the stereo mode, and for the output rate.
170 *****************************************************************************/
171 static int aout_SetFormat( aout_thread_t *p_aout )
173 /* TODO: finish and clean this */
174 SDL_AudioSpec desired;
175 int i_stereo = p_aout->b_stereo ? 2 : 1;
177 /*i_format = p_aout->i_format;*/
178 desired.freq = p_aout->l_rate; /* Set the output rate */
179 desired.format = AUDIO_S16LSB; /* stereo 16 bits */
180 desired.channels = i_stereo;
181 desired.callback = aout_SDLCallback;
182 desired.userdata = p_aout->p_sys;
183 desired.samples = 2048;
185 /* Open the sound device */
189 if( SDL_OpenAudio( &desired, NULL ) < 0 )
191 p_aout->p_sys->b_active = 0;
195 p_aout->p_sys->b_active = 1;
201 /*****************************************************************************
202 * aout_GetBufInfo: buffer status query
203 *****************************************************************************
204 * returns the number of bytes in the audio buffer compared to the size of
206 *****************************************************************************/
207 static long aout_GetBufInfo( aout_thread_t *p_aout, long l_buffer_limit )
209 if(l_buffer_limit > p_aout->p_sys->i_audio_end)
211 /* returning 0 here juste gives awful sound in the speakers :/ */
212 return( l_buffer_limit );
214 return( p_aout->p_sys->i_audio_end - l_buffer_limit);
217 /*****************************************************************************
218 * aout_Play: play a sound samples buffer
219 *****************************************************************************
220 * This function writes a buffer of i_length bytes in the dsp
221 *****************************************************************************/
222 static void aout_Play( aout_thread_t *p_aout, byte_t *buffer, int i_size )
224 byte_t * audio_buf = p_aout->p_sys->audio_buf;
226 SDL_LockAudio(); /* Stop callbacking */
228 p_aout->p_sys->audio_buf = realloc( audio_buf,
229 p_aout->p_sys->i_audio_end + i_size);
230 memcpy( p_aout->p_sys->audio_buf + p_aout->p_sys->i_audio_end,
233 p_aout->p_sys->i_audio_end += i_size;
235 SDL_UnlockAudio(); /* go on callbacking */
238 /*****************************************************************************
239 * aout_Close: close the audio device
240 *****************************************************************************/
241 static void aout_Close( aout_thread_t *p_aout )
243 if( p_aout->p_sys->b_active )
245 SDL_PauseAudio( 1 ); /* pause audio */
247 if( p_aout->p_sys->audio_buf != NULL ) /* do we have a buffer now ? */
249 free( p_aout->p_sys->audio_buf );
255 SDL_QuitSubSystem( SDL_INIT_AUDIO );
257 free( p_aout->p_sys ); /* Close the Output. */
260 /*****************************************************************************
261 * aout_SDLCallback: what to do once SDL has played sound samples
262 *****************************************************************************/
263 static void aout_SDLCallback( void *userdata, byte_t *stream, int len )
265 struct aout_sys_s * p_sys = userdata;
267 if( p_sys->i_audio_end > OVERFLOWLIMIT )
269 intf_ErrMsg( "aout error: aout_SDLCallback overflowed" );
271 free( p_sys->audio_buf );
272 p_sys->audio_buf = NULL;
274 p_sys->i_audio_end = 0;
275 /* we've gone to slow, increase output freq */
278 /* if we are not in underrun */
279 if( p_sys->i_audio_end > len )
281 p_sys->i_audio_end -= len;
282 memcpy( stream, p_sys->audio_buf, len );
283 memmove( p_sys->audio_buf, p_sys->audio_buf + len, p_sys->i_audio_end );