1 /*****************************************************************************
2 * sdl.c : SDL audio output plugin for vlc
3 *****************************************************************************
4 * Copyright (C) 2000-2002 VideoLAN
5 * $Id: sdl.c,v 1.15 2002/11/14 22:38:47 massiot 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 module") );
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;
83 /* Check that no one uses the DSP. */
84 Uint32 i_flags = SDL_INIT_AUDIO;
85 if( SDL_WasInit( i_flags ) )
91 /* Win32 SDL implementation doesn't support SDL_INIT_EVENTTHREAD yet */
92 i_flags |= SDL_INIT_EVENTTHREAD;
95 /* In debug mode you may want vlc to dump a core instead of staying
97 i_flags |= SDL_INIT_NOPARACHUTE;
100 /* Initialize library */
101 if( SDL_Init( i_flags ) < 0 )
103 msg_Err( p_aout, "cannot initialize SDL (%s)", SDL_GetError() );
107 if ( var_Type( p_aout, "audio-device" ) ==
108 (VLC_VAR_STRING | VLC_VAR_ISLIST) )
110 /* The user has selected an audio device. */
112 var_Get( p_aout, "audio-device", &val );
113 if ( !strcmp( val.psz_string, N_("Stereo") ) )
115 p_aout->output.output.i_physical_channels
116 = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
118 else if ( !strcmp( val.psz_string, N_("Mono") ) )
120 p_aout->output.output.i_physical_channels = AOUT_CHAN_CENTER;
122 free( val.psz_string );
125 i_nb_channels = aout_FormatNbChannels( &p_aout->output.output );
126 if ( i_nb_channels > 2 )
128 /* SDL doesn't support more than two channels. */
130 p_aout->output.output.i_physical_channels
131 = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
133 desired.freq = p_aout->output.output.i_rate;
134 desired.format = AUDIO_S16SYS;
135 desired.channels = i_nb_channels;
136 desired.callback = SDLCallback;
137 desired.userdata = p_aout;
138 desired.samples = FRAME_SIZE;
140 /* Open the sound device. */
141 if( SDL_OpenAudio( &desired, &obtained ) < 0 )
148 /* Now have a look at what we got. */
149 switch ( obtained.format )
152 p_aout->output.output.i_format = VLC_FOURCC('s','1','6','l'); break;
154 p_aout->output.output.i_format = VLC_FOURCC('s','1','6','b'); break;
156 p_aout->output.output.i_format = VLC_FOURCC('u','1','6','l'); break;
158 p_aout->output.output.i_format = VLC_FOURCC('u','1','6','b'); break;
160 p_aout->output.output.i_format = VLC_FOURCC('s','8',' ',' '); break;
162 p_aout->output.output.i_format = VLC_FOURCC('u','8',' ',' '); break;
164 /* Volume is entirely done in software. */
165 aout_VolumeSoftInit( p_aout );
167 if ( obtained.channels != i_nb_channels )
169 p_aout->output.output.i_physical_channels = (obtained.channels == 2 ?
170 AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT :
173 if ( var_Type( p_aout, "audio-device" ) < 0 )
176 var_Create( p_aout, "audio-device", VLC_VAR_STRING | VLC_VAR_ISLIST );
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 )
188 var_Create( p_aout, "audio-device", VLC_VAR_STRING | VLC_VAR_ISLIST );
189 val.psz_string = N_("Stereo");
190 var_Change( p_aout, "audio-device", VLC_VAR_ADDCHOICE, &val );
191 val.psz_string = N_("Mono");
192 var_Change( p_aout, "audio-device", VLC_VAR_ADDCHOICE, &val );
193 if ( i_nb_channels == 2 )
195 val.psz_string = N_("Stereo");
199 val.psz_string = N_("Mono");
201 var_Change( p_aout, "audio-device", VLC_VAR_SETDEFAULT, &val );
203 var_AddCallback( p_aout, "audio-device", aout_ChannelsRestart,
207 p_aout->output.output.i_rate = obtained.freq;
208 p_aout->output.i_nb_samples = obtained.samples;
209 p_aout->output.pf_play = Play;
214 /*****************************************************************************
215 * Play: play a sound samples buffer
216 *****************************************************************************/
217 static void Play( aout_instance_t * p_aout )
221 /*****************************************************************************
222 * Close: close the audio device
223 *****************************************************************************/
224 static void Close ( vlc_object_t *p_this )
228 SDL_QuitSubSystem( SDL_INIT_AUDIO );
231 /*****************************************************************************
232 * SDLCallback: what to do once SDL has played sound samples
233 *****************************************************************************/
234 static void SDLCallback( void * _p_aout, byte_t * p_stream, int i_len )
236 aout_instance_t * p_aout = (aout_instance_t *)_p_aout;
237 aout_buffer_t * p_buffer;
239 /* SDL is unable to call us at regular times, or tell us its current
240 * hardware latency, or the buffer state. So we just pop data and throw
241 * it at SDL's face. Nah. */
243 vlc_mutex_lock( &p_aout->output_fifo_lock );
244 p_buffer = aout_FifoPop( p_aout, &p_aout->output.fifo );
245 vlc_mutex_unlock( &p_aout->output_fifo_lock );
247 if ( p_buffer != NULL )
249 p_aout->p_vlc->pf_memcpy( p_stream, p_buffer->p_buffer, i_len );
250 aout_BufferFree( p_buffer );
254 p_aout->p_vlc->pf_memset( p_stream, 0, i_len );