1 /*****************************************************************************
2 * sdl.c : SDL audio output plugin for vlc
3 *****************************************************************************
4 * Copyright (C) 2000-2002 VideoLAN
5 * $Id: sdl.c,v 1.21 2003/03/30 18:14:36 gbazin Exp $
7 * Authors: Michel Kaempf <maxx@via.ecp.fr>
8 * Samuel Hocevar <sam@zoy.org>
9 * Pierre Baillet <oct@zoy.org>
10 * Christophe Massiot <massiot@via.ecp.fr>
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
25 *****************************************************************************/
27 /*****************************************************************************
29 *****************************************************************************/
30 #include <errno.h> /* ENOMEM */
31 #include <fcntl.h> /* open(), O_WRONLY */
32 #include <string.h> /* strerror() */
33 #include <unistd.h> /* write(), close() */
34 #include <stdlib.h> /* calloc(), malloc(), free() */
38 #include "aout_internal.h"
40 #include SDL_INCLUDE_FILE
42 #define FRAME_SIZE 2048
44 /*****************************************************************************
45 * aout_sys_t: SDL audio output method descriptor
46 *****************************************************************************
47 * This structure is part of the audio output thread descriptor.
48 * It describes the specific properties of an audio device.
49 *****************************************************************************/
56 /*****************************************************************************
58 *****************************************************************************/
59 static int Open ( vlc_object_t * );
60 static void Close ( vlc_object_t * );
61 static void Play ( aout_instance_t * );
62 static void SDLCallback ( void *, byte_t *, int );
64 /*****************************************************************************
66 *****************************************************************************/
68 set_description( _("Simple DirectMedia Layer audio output") );
69 set_capability( "audio output", 40 );
70 add_shortcut( "sdl" );
71 set_callbacks( Open, Close );
74 /*****************************************************************************
75 * Open: open the audio device
76 *****************************************************************************/
77 static int Open ( vlc_object_t *p_this )
79 aout_instance_t *p_aout = (aout_instance_t *)p_this;
80 SDL_AudioSpec desired, obtained;
84 /* Check that no one uses the DSP. */
85 Uint32 i_flags = SDL_INIT_AUDIO;
86 if( SDL_WasInit( i_flags ) )
92 /* Win32 SDL implementation doesn't support SDL_INIT_EVENTTHREAD yet */
93 i_flags |= SDL_INIT_EVENTTHREAD;
96 /* In debug mode you may want vlc to dump a core instead of staying
98 i_flags |= SDL_INIT_NOPARACHUTE;
101 /* Initialize library */
102 if( SDL_Init( i_flags ) < 0 )
104 msg_Err( p_aout, "cannot initialize SDL (%s)", SDL_GetError() );
108 if ( var_Type( p_aout, "audio-device" ) ==
109 (VLC_VAR_STRING | VLC_VAR_HASCHOICE) )
111 /* The user has selected an audio device. */
113 var_Get( p_aout, "audio-device", &val );
114 if ( !strcmp( val.psz_string, N_("Stereo") ) )
116 p_aout->output.output.i_physical_channels
117 = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
119 else if ( !strcmp( val.psz_string, N_("Mono") ) )
121 p_aout->output.output.i_physical_channels = AOUT_CHAN_CENTER;
123 free( val.psz_string );
126 i_nb_channels = aout_FormatNbChannels( &p_aout->output.output );
127 if ( i_nb_channels > 2 )
129 /* SDL doesn't support more than two channels. */
131 p_aout->output.output.i_physical_channels
132 = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
134 desired.freq = p_aout->output.output.i_rate;
135 desired.format = AUDIO_S16SYS;
136 desired.channels = i_nb_channels;
137 desired.callback = SDLCallback;
138 desired.userdata = p_aout;
139 desired.samples = FRAME_SIZE;
141 /* Open the sound device. */
142 if( SDL_OpenAudio( &desired, &obtained ) < 0 )
149 /* Now have a look at what we got. */
150 switch ( obtained.format )
153 p_aout->output.output.i_format = VLC_FOURCC('s','1','6','l'); break;
155 p_aout->output.output.i_format = VLC_FOURCC('s','1','6','b'); break;
157 p_aout->output.output.i_format = VLC_FOURCC('u','1','6','l'); break;
159 p_aout->output.output.i_format = VLC_FOURCC('u','1','6','b'); break;
161 p_aout->output.output.i_format = VLC_FOURCC('s','8',' ',' '); break;
163 p_aout->output.output.i_format = VLC_FOURCC('u','8',' ',' '); break;
165 /* Volume is entirely done in software. */
166 aout_VolumeSoftInit( p_aout );
168 if ( obtained.channels != i_nb_channels )
170 p_aout->output.output.i_physical_channels = (obtained.channels == 2 ?
171 AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT :
174 if ( var_Type( p_aout, "audio-device" ) == 0 )
176 var_Create( p_aout, "audio-device", VLC_VAR_STRING | VLC_VAR_HASCHOICE );
177 val.psz_string = (obtained.channels == 2) ? N_("Stereo") :
179 var_Change( p_aout, "audio-device", VLC_VAR_ADDCHOICE, &val );
180 var_AddCallback( p_aout, "audio-device", aout_ChannelsRestart,
184 else if ( var_Type( p_aout, "audio-device" ) == 0 )
187 var_Create( p_aout, "audio-device", VLC_VAR_STRING | VLC_VAR_HASCHOICE );
188 val.psz_string = N_("Stereo");
189 var_Change( p_aout, "audio-device", VLC_VAR_ADDCHOICE, &val );
190 val.psz_string = N_("Mono");
191 var_Change( p_aout, "audio-device", VLC_VAR_ADDCHOICE, &val );
192 if ( i_nb_channels == 2 )
194 val.psz_string = N_("Stereo");
198 val.psz_string = N_("Mono");
200 var_Change( p_aout, "audio-device", VLC_VAR_SETDEFAULT, &val );
201 var_AddCallback( p_aout, "audio-device", aout_ChannelsRestart,
205 val.b_bool = VLC_TRUE;
206 var_Set( p_aout, "intf-change", val );
208 p_aout->output.output.i_rate = obtained.freq;
209 p_aout->output.i_nb_samples = obtained.samples;
210 p_aout->output.pf_play = Play;
215 /*****************************************************************************
216 * Play: play a sound samples buffer
217 *****************************************************************************/
218 static void Play( aout_instance_t * p_aout )
222 /*****************************************************************************
223 * Close: close the audio device
224 *****************************************************************************/
225 static void Close ( vlc_object_t *p_this )
229 SDL_QuitSubSystem( SDL_INIT_AUDIO );
232 /*****************************************************************************
233 * SDLCallback: what to do once SDL has played sound samples
234 *****************************************************************************/
235 static void SDLCallback( void * _p_aout, byte_t * p_stream, int i_len )
237 aout_instance_t * p_aout = (aout_instance_t *)_p_aout;
238 aout_buffer_t * p_buffer;
240 /* SDL is unable to call us at regular times, or tell us its current
241 * hardware latency, or the buffer state. So we just pop data and throw
242 * it at SDL's face. Nah. */
244 vlc_mutex_lock( &p_aout->output_fifo_lock );
245 p_buffer = aout_FifoPop( p_aout, &p_aout->output.fifo );
246 vlc_mutex_unlock( &p_aout->output_fifo_lock );
248 if ( p_buffer != NULL )
250 p_aout->p_vlc->pf_memcpy( p_stream, p_buffer->p_buffer, i_len );
251 aout_BufferFree( p_buffer );
255 p_aout->p_vlc->pf_memset( p_stream, 0, i_len );