modules/audio_output/sdl.c

   1 /*****************************************************************************
   2  * sdl.c : SDL audio output plugin for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2000-2002 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Michel Kaempf <maxx@via.ecp.fr>
   8  *          Sam Hocevar <sam@zoy.org>
   9  *          Pierre Baillet <oct@zoy.org>
  10  *          Christophe Massiot <massiot@via.ecp.fr>
  11  *
  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.
  16  *
  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.
  21  *
  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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  25  *****************************************************************************/
  26
  27 /*****************************************************************************
  28  * Preamble
  29  *****************************************************************************/
  30 #include <unistd.h>                                      /* write(), close() */
  31
  32 #ifdef HAVE_CONFIG_H
  33 # include "config.h"
  34 #endif
  35
  36 #include <vlc/vlc.h>
  37 #include <vlc_aout.h>
  38
  39 #include SDL_INCLUDE_FILE
  40
  41 #define FRAME_SIZE 2048
  42
  43 /*****************************************************************************
  44  * aout_sys_t: SDL audio output method descriptor
  45  *****************************************************************************
  46  * This structure is part of the audio output thread descriptor.
  47  * It describes the specific properties of an audio device.
  48  *****************************************************************************/
  49 struct aout_sys_t
  50 {
  51     mtime_t next_date;
  52     mtime_t buffer_time;
  53 };
  54
  55 /*****************************************************************************
  56  * Local prototypes
  57  *****************************************************************************/
  58 static int  Open        ( vlc_object_t * );
  59 static void Close       ( vlc_object_t * );
  60 static void Play        ( aout_instance_t * );
  61 static void SDLCallback ( void *, byte_t *, int );
  62
  63 /*****************************************************************************
  64  * Module descriptor
  65  *****************************************************************************/
  66 vlc_module_begin();
  67     set_shortname( "SDL" );
  68     set_description( _("Simple DirectMedia Layer audio output") );
  69     set_capability( "audio output", 40 );
  70     set_category( CAT_AUDIO );
  71     set_subcategory( SUBCAT_AUDIO_AOUT );
  72     add_shortcut( "sdl" );
  73     set_callbacks( Open, Close );
  74 vlc_module_end();
  75
  76 /*****************************************************************************
  77  * Open: open the audio device
  78  *****************************************************************************/
  79 static int Open ( vlc_object_t *p_this )
  80 {
  81     aout_instance_t *p_aout = (aout_instance_t *)p_this;
  82     SDL_AudioSpec desired, obtained;
  83     int i_nb_channels;
  84     vlc_value_t val, text;
  85
  86     /* Check that no one uses the DSP. */
  87     uint32_t i_flags = SDL_INIT_AUDIO;
  88     if( SDL_WasInit( i_flags ) )
  89     {
  90         return VLC_EGENERIC;
  91     }
  92
  93 #ifndef WIN32
  94     /* Win32 SDL implementation doesn't support SDL_INIT_EVENTTHREAD yet */
  95     i_flags |= SDL_INIT_EVENTTHREAD;
  96 #endif
  97 #ifndef NDEBUG
  98     /* In debug mode you may want vlc to dump a core instead of staying
  99      * stuck */
 100     i_flags |= SDL_INIT_NOPARACHUTE;
 101 #endif
 102
 103     /* Initialize library */
 104     if( SDL_Init( i_flags ) < 0 )
 105     {
 106         msg_Err( p_aout, "cannot initialize SDL (%s)", SDL_GetError() );
 107         return VLC_EGENERIC;
 108     }
 109
 110     if ( var_Type( p_aout, "audio-device" ) != 0 )
 111     {
 112         /* The user has selected an audio device. */
 113         vlc_value_t val;
 114         var_Get( p_aout, "audio-device", &val );
 115         if ( val.i_int == AOUT_VAR_STEREO )
 116         {
 117             p_aout->output.output.i_physical_channels
 118                 = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 119         }
 120         else if ( val.i_int == AOUT_VAR_MONO )
 121         {
 122             p_aout->output.output.i_physical_channels = AOUT_CHAN_CENTER;
 123         }
 124     }
 125
 126     i_nb_channels = aout_FormatNbChannels( &p_aout->output.output );
 127     if ( i_nb_channels > 2 )
 128     {
 129         /* SDL doesn't support more than two channels. */
 130         i_nb_channels = 2;
 131         p_aout->output.output.i_physical_channels
 132             = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 133     }
 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;
 140
 141     /* Open the sound device. */
 142     if( SDL_OpenAudio( &desired, &obtained ) < 0 )
 143     {
 144         return VLC_EGENERIC;
 145     }
 146
 147     SDL_PauseAudio( 0 );
 148
 149     /* Now have a look at what we got. */
 150     switch ( obtained.format )
 151     {
 152     case AUDIO_S16LSB:
 153         p_aout->output.output.i_format = VLC_FOURCC('s','1','6','l'); break;
 154     case AUDIO_S16MSB:
 155         p_aout->output.output.i_format = VLC_FOURCC('s','1','6','b'); break;
 156     case AUDIO_U16LSB:
 157         p_aout->output.output.i_format = VLC_FOURCC('u','1','6','l'); break;
 158     case AUDIO_U16MSB:
 159         p_aout->output.output.i_format = VLC_FOURCC('u','1','6','b'); break;
 160     case AUDIO_S8:
 161         p_aout->output.output.i_format = VLC_FOURCC('s','8',' ',' '); break;
 162     case AUDIO_U8:
 163         p_aout->output.output.i_format = VLC_FOURCC('u','8',' ',' '); break;
 164     }
 165     /* Volume is entirely done in software. */
 166     aout_VolumeSoftInit( p_aout );
 167
 168     if ( obtained.channels != i_nb_channels )
 169     {
 170         p_aout->output.output.i_physical_channels = (obtained.channels == 2 ?
 171                                             AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT :
 172                                             AOUT_CHAN_CENTER);
 173
 174         if ( var_Type( p_aout, "audio-device" ) == 0 )
 175         {
 176             var_Create( p_aout, "audio-device",
 177                         VLC_VAR_INTEGER | VLC_VAR_HASCHOICE );
 178             text.psz_string = _("Audio Device");
 179             var_Change( p_aout, "audio-device", VLC_VAR_SETTEXT, &text, NULL );
 180
 181             val.i_int = (obtained.channels == 2) ? AOUT_VAR_STEREO :
 182                         AOUT_VAR_MONO;
 183             text.psz_string = (obtained.channels == 2) ? N_("Stereo") :
 184                               N_("Mono");
 185             var_Change( p_aout, "audio-device",
 186                         VLC_VAR_ADDCHOICE, &val, &text );
 187             var_AddCallback( p_aout, "audio-device", aout_ChannelsRestart,
 188                              NULL );
 189         }
 190     }
 191     else if ( var_Type( p_aout, "audio-device" ) == 0 )
 192     {
 193         /* First launch. */
 194         var_Create( p_aout, "audio-device",
 195                     VLC_VAR_INTEGER | VLC_VAR_HASCHOICE );
 196         text.psz_string = _("Audio Device");
 197         var_Change( p_aout, "audio-device", VLC_VAR_SETTEXT, &text, NULL );
 198
 199         val.i_int = AOUT_VAR_STEREO;
 200         text.psz_string = N_("Stereo");
 201         var_Change( p_aout, "audio-device", VLC_VAR_ADDCHOICE, &val, &text );
 202         val.i_int = AOUT_VAR_MONO;
 203         text.psz_string = N_("Mono");
 204         var_Change( p_aout, "audio-device", VLC_VAR_ADDCHOICE, &val, &text );
 205         if ( i_nb_channels == 2 )
 206         {
 207             val.i_int = AOUT_VAR_STEREO;
 208         }
 209         else
 210         {
 211             val.i_int = AOUT_VAR_MONO;
 212         }
 213         var_Change( p_aout, "audio-device", VLC_VAR_SETDEFAULT, &val, NULL );
 214         var_AddCallback( p_aout, "audio-device", aout_ChannelsRestart, NULL );
 215     }
 216
 217     val.b_bool = VLC_TRUE;
 218     var_Set( p_aout, "intf-change", val );
 219
 220     p_aout->output.output.i_rate = obtained.freq;
 221     p_aout->output.i_nb_samples = obtained.samples;
 222     p_aout->output.pf_play = Play;
 223
 224     return VLC_SUCCESS;
 225 }
 226
 227 /*****************************************************************************
 228  * Play: play a sound samples buffer
 229  *****************************************************************************/
 230 static void Play( aout_instance_t * p_aout )
 231 {
 232     VLC_UNUSED(p_aout);
 233 }
 234
 235 /*****************************************************************************
 236  * Close: close the audio device
 237  *****************************************************************************/
 238 static void Close ( vlc_object_t *p_this )
 239 {
 240     VLC_UNUSED(p_this);
 241     SDL_PauseAudio( 1 );
 242     SDL_CloseAudio();
 243     SDL_QuitSubSystem( SDL_INIT_AUDIO );
 244 }
 245
 246 /*****************************************************************************
 247  * SDLCallback: what to do once SDL has played sound samples
 248  *****************************************************************************/
 249 static void SDLCallback( void * _p_aout, byte_t * p_stream, int i_len )
 250 {
 251     aout_instance_t * p_aout = (aout_instance_t *)_p_aout;
 252     aout_buffer_t *   p_buffer;
 253
 254     /* SDL is unable to call us at regular times, or tell us its current
 255      * hardware latency, or the buffer state. So we just pop data and throw
 256      * it at SDL's face. Nah. */
 257
 258     vlc_mutex_lock( &p_aout->output_fifo_lock );
 259     p_buffer = aout_FifoPop( p_aout, &p_aout->output.fifo );
 260     vlc_mutex_unlock( &p_aout->output_fifo_lock );
 261
 262     if ( p_buffer != NULL )
 263     {
 264         p_aout->p_libvlc->pf_memcpy( p_stream, p_buffer->p_buffer, i_len );
 265         aout_BufferFree( p_buffer );
 266     }
 267     else
 268     {
 269         p_aout->p_libvlc->pf_memset( p_stream, 0, i_len );
 270     }
 271 }
 272