directx.c

/*****************************************************************************
 * directx.c: Windows DirectX audio output method
 *****************************************************************************
 * Copyright (C) 2001-2009 the VideoLAN team
 * $Id$
 *
 * Authors: Gildas Bazin <gbazin@videolan.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_aout.h>
#include <vlc_charset.h>
#include <vlc_atomic.h>

#include "windows_audio_common.h"

#define FRAME_SIZE ((int)p_aout->format.i_rate/20) /* Size in samples */

/*****************************************************************************
 * notification_thread_t: DirectX event thread
 *****************************************************************************/
typedef struct notification_thread_t
{
    audio_output_t *p_aout;
    int i_frame_size;                          /* size in bytes of one frame */
    int i_write_slot;       /* current write position in our circular buffer */

    mtime_t start_date;
    HANDLE event;

    vlc_thread_t thread;
    vlc_atomic_t abort;

} notification_thread_t;

/*****************************************************************************
 * aout_sys_t: directx audio output method descriptor
 *****************************************************************************
 * This structure is part of the audio output thread descriptor.
 * It describes the direct sound specific properties of an audio device.
 *****************************************************************************/
struct aout_sys_t
{
    HINSTANCE           hdsound_dll;      /* handle of the opened dsound dll */

    char *              psz_device;              /* user defined device name */
    LPGUID              p_device_guid;

    LPDIRECTSOUND       p_dsobject;              /* main Direct Sound object */
    LPDIRECTSOUNDBUFFER p_dsbuffer;   /* the sound buffer we use (direct sound
                                       * takes care of mixing all the
                                       * secondary buffers into the primary) */

    notification_thread_t *p_notif;                  /* DirectSoundThread id */

    int      b_playing;                                    /* playing status */

    int      i_frame_size;                     /* Size in bytes of one frame */

    int      i_speaker_setup;                      /* Speaker setup override */

    bool     b_chan_reorder;                /* do we need channel reordering */
    int      pi_chan_table[AOUT_CHAN_MAX];
    uint32_t i_channel_mask;
    uint32_t i_bits_per_sample;
    uint32_t i_channels;
};

/*****************************************************************************
 * Local prototypes.
 *****************************************************************************/
static int  OpenAudio  ( vlc_object_t * );
static void CloseAudio ( vlc_object_t * );
static void Play       ( audio_output_t * );

/* local functions */
static void Probe             ( audio_output_t * );
static int  InitDirectSound   ( audio_output_t * );
static int  CreateDSBuffer    ( audio_output_t *, int, int, int, int, int, bool );
static int  CreateDSBufferPCM ( audio_output_t *, vlc_fourcc_t*, int, int, int, bool );
static void DestroyDSBuffer   ( audio_output_t * );
static void* DirectSoundThread( void * );
static int  FillBuffer        ( audio_output_t *, int, aout_buffer_t * );

static int ReloadDirectXDevices( vlc_object_t *, char const *,
                                vlc_value_t, vlc_value_t, void * );

/* Speaker setup override options list */
static const char *const speaker_list[] = { "Windows default", "Mono", "Stereo",
                                            "Quad", "5.1", "7.1" };
static const char *const ppsz_adev[] = {"default",  };
static const char *const ppsz_adev_text[] = {"default", };

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
#define DEVICE_TEXT N_("Output device")
#define DEVICE_LONGTEXT N_("Select your audio output device")

#define SPEAKER_TEXT N_("Speaker configuration")
#define SPEAKER_LONGTEXT N_("Select speaker configuration you want to use. " \
    "This option doesn't upmix! So NO e.g. Stereo -> 5.1 conversion." )

vlc_module_begin ()
    set_description( N_("DirectX audio output") )
    set_shortname( "DirectX" )
    set_capability( "audio output", 100 )
    set_category( CAT_AUDIO )
    set_subcategory( SUBCAT_AUDIO_AOUT )
    add_shortcut( "directx", "directsound" )

    add_string( "directx-audio-device-name", "default",
             DEVICE_TEXT, DEVICE_LONGTEXT, false )
        add_deprecated_alias( "directx-audio-device" ) /* Since 1.1.0 */
        change_string_list( ppsz_adev, ppsz_adev_text, ReloadDirectXDevices )
        change_action_add( ReloadDirectXDevices, N_("Refresh list") )
    add_bool( "directx-audio-float32", false, FLOAT_TEXT,
              FLOAT_LONGTEXT, true )
    add_string( "directx-audio-speaker", "Windows default",
                 SPEAKER_TEXT, SPEAKER_LONGTEXT, true )
        change_string_list( speaker_list, 0, 0 )

    set_callbacks( OpenAudio, CloseAudio )
vlc_module_end ()

/*****************************************************************************
 * OpenAudio: open the audio device
 *****************************************************************************
 * This function opens and setups Direct Sound.
 *****************************************************************************/
static int OpenAudio( vlc_object_t *p_this )
{
    audio_output_t * p_aout = (audio_output_t *)p_this;
    vlc_value_t val;
    char * psz_speaker;
    int i = 0;

    const char * const * ppsz_compare = speaker_list;

    msg_Dbg( p_aout, "Opening DirectSound Audio Output" );

   /* Allocate structure */
    p_aout->sys = malloc( sizeof( aout_sys_t ) );
    if( p_aout->sys == NULL )
        return VLC_ENOMEM;

    /* Initialize some variables */
    p_aout->sys->p_dsobject = NULL;
    p_aout->sys->p_dsbuffer = NULL;
    p_aout->sys->p_notif = NULL;
    p_aout->sys->b_playing = 0;

    p_aout->pf_play = Play;
    p_aout->pf_pause = NULL;
    p_aout->pf_flush = NULL;
    aout_VolumeSoftInit( p_aout );

    /* Retrieve config values */
    var_Create( p_aout, "directx-audio-float32",
                VLC_VAR_BOOL | VLC_VAR_DOINHERIT );
    psz_speaker = var_CreateGetString( p_aout, "directx-audio-speaker" );

    while ( *ppsz_compare != NULL )
    {
        if ( !strncmp( *ppsz_compare, psz_speaker, strlen(*ppsz_compare) ) )
        {
            break;
        }
        ppsz_compare++; i++;
    }

    if ( *ppsz_compare == NULL )
    {
        msg_Err( p_aout, "(%s) isn't valid speaker setup option", psz_speaker );
        msg_Err( p_aout, "Defaulting to Windows default speaker config");
        i = 0;
    }
    free( psz_speaker );
    p_aout->sys->i_speaker_setup = i;

    p_aout->sys->p_device_guid = 0;

    /* Initialise DirectSound */
    if( InitDirectSound( p_aout ) )
    {
        msg_Err( p_aout, "cannot initialize DirectSound" );
        goto error;
    }

    if( var_Type( p_aout, "audio-device" ) == 0 )
    {
        Probe( p_aout );
    }

    if( var_Get( p_aout, "audio-device", &val ) < 0 )
    {
        /* Probe() has failed. */
        goto error;
    }

    /* Open the device */
    if( val.i_int == AOUT_VAR_SPDIF )
    {
        p_aout->format.i_format = VLC_CODEC_SPDIFL;

        /* Calculate the frame size in bytes */
        p_aout->i_nb_samples = A52_FRAME_NB;
        p_aout->format.i_bytes_per_frame = AOUT_SPDIF_SIZE;
        p_aout->format.i_frame_length = A52_FRAME_NB;
        p_aout->sys->i_frame_size = p_aout->format.i_bytes_per_frame;

        if( CreateDSBuffer( p_aout, VLC_CODEC_SPDIFL,
                            p_aout->format.i_physical_channels,
                            aout_FormatNbChannels( &p_aout->format ),
                            p_aout->format.i_rate,
                            p_aout->sys->i_frame_size, false )
            != VLC_SUCCESS )
        {
            msg_Err( p_aout, "cannot open directx audio device" );
            free( p_aout->sys );
            return VLC_EGENERIC;
        }

        aout_VolumeNoneInit( p_aout );
    }
    else
    {
        if( val.i_int == AOUT_VAR_5_1 )
        {
            p_aout->format.i_physical_channels
                = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
                   | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
                   | AOUT_CHAN_LFE;
        }
        else if( val.i_int == AOUT_VAR_7_1 )
        {
                    p_aout->format.i_physical_channels
                        = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
                           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
                           | AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT
                           | AOUT_CHAN_LFE;
        }
        else if( val.i_int == AOUT_VAR_3F2R )
        {
            p_aout->format.i_physical_channels
                = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
                   | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
        }
        else if( val.i_int == AOUT_VAR_2F2R )
        {
            p_aout->format.i_physical_channels
                = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
                   | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
        }
        else if( val.i_int == AOUT_VAR_MONO )
        {
            p_aout->format.i_physical_channels = AOUT_CHAN_CENTER;
        }
        else
        {
            p_aout->format.i_physical_channels
                = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
        }

        if( CreateDSBufferPCM( p_aout, &p_aout->format.i_format,
                               p_aout->format.i_physical_channels,
                               aout_FormatNbChannels( &p_aout->format ),
                               p_aout->format.i_rate, false )
            != VLC_SUCCESS )
        {
            msg_Err( p_aout, "cannot open directx audio device" );
            free( p_aout->sys );
            return VLC_EGENERIC;
        }

        /* Calculate the frame size in bytes */
        p_aout->i_nb_samples = FRAME_SIZE;
        aout_FormatPrepare( &p_aout->format );
        aout_VolumeSoftInit( p_aout );
    }

    /* Now we need to setup our DirectSound play notification structure */
    p_aout->sys->p_notif = calloc( 1, sizeof( *p_aout->sys->p_notif ) );
    p_aout->sys->p_notif->p_aout = p_aout;

    vlc_atomic_set(&p_aout->sys->p_notif->abort, 0);
    p_aout->sys->p_notif->event = CreateEvent( 0, FALSE, FALSE, 0 );
    p_aout->sys->p_notif->i_frame_size =  p_aout->sys->i_frame_size;

    /* then launch the notification thread */
    msg_Dbg( p_aout, "creating DirectSoundThread" );
    if( vlc_clone( &p_aout->sys->p_notif->thread,
                   DirectSoundThread, p_aout->sys->p_notif,
                   VLC_THREAD_PRIORITY_HIGHEST ) )
    {
        msg_Err( p_aout, "cannot create DirectSoundThread" );
        CloseHandle( p_aout->sys->p_notif->event );
        free( p_aout->sys->p_notif );
        p_aout->sys->p_notif = NULL;
        goto error;
    }

    return VLC_SUCCESS;

 error:
    CloseAudio( VLC_OBJECT(p_aout) );
    return VLC_EGENERIC;
}

/*****************************************************************************
 * Probe: probe the audio device for available formats and channels
 *****************************************************************************/
static void Probe( audio_output_t * p_aout )
{
    vlc_value_t val, text;
    vlc_fourcc_t i_format;
    unsigned int i_physical_channels;
    DWORD ui_speaker_config;
    bool is_default_output_set = false;

    var_Create( p_aout, "audio-device", VLC_VAR_INTEGER | VLC_VAR_HASCHOICE );
    text.psz_string = _("Audio Device");
    var_Change( p_aout, "audio-device", VLC_VAR_SETTEXT, &text, NULL );

    /* Test for 5.1 support */
    i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
                          AOUT_CHAN_CENTER | AOUT_CHAN_REARLEFT |
                          AOUT_CHAN_REARRIGHT | AOUT_CHAN_LFE;
    if( p_aout->format.i_physical_channels == i_physical_channels )
    {
        if( CreateDSBufferPCM( p_aout, &i_format, i_physical_channels, 6,
                               p_aout->format.i_rate, true )
            == VLC_SUCCESS )
        {
            val.i_int = AOUT_VAR_5_1;
            text.psz_string = (char*) "5.1";
            var_Change( p_aout, "audio-device",
                        VLC_VAR_ADDCHOICE, &val, &text );
            var_Change( p_aout, "audio-device", VLC_VAR_SETDEFAULT, &val, NULL );
            is_default_output_set = true;
            msg_Dbg( p_aout, "device supports 5.1 channels" );
        }
    }

    /* Test for 7.1 support */
    i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
                             AOUT_CHAN_CENTER | AOUT_CHAN_REARLEFT |
                             AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT |
                             AOUT_CHAN_REARRIGHT | AOUT_CHAN_LFE;
    if( p_aout->format.i_physical_channels == i_physical_channels )
    {
        if( CreateDSBufferPCM( p_aout, &i_format, i_physical_channels, 8,
                                  p_aout->format.i_rate, true )
            == VLC_SUCCESS )
        {
            val.i_int = AOUT_VAR_7_1;
            text.psz_string = (char*) "7.1";
            var_Change( p_aout, "audio-device",
                        VLC_VAR_ADDCHOICE, &val, &text );
            var_Change( p_aout, "audio-device", VLC_VAR_SETDEFAULT, &val, NULL );
            is_default_output_set = true;
            msg_Dbg( p_aout, "device supports 7.1 channels" );
        }
    }

    /* Test for 3 Front 2 Rear support */
    i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
                          AOUT_CHAN_CENTER | AOUT_CHAN_REARLEFT |
                          AOUT_CHAN_REARRIGHT;
    if( p_aout->format.i_physical_channels == i_physical_channels )
    {
        if( CreateDSBufferPCM( p_aout, &i_format, i_physical_channels, 5,
                               p_aout->format.i_rate, true )
            == VLC_SUCCESS )
        {
            val.i_int = AOUT_VAR_3F2R;
            text.psz_string = _("3 Front 2 Rear");
            var_Change( p_aout, "audio-device",
                        VLC_VAR_ADDCHOICE, &val, &text );
            if(!is_default_output_set)
            {
                var_Change( p_aout, "audio-device", VLC_VAR_SETDEFAULT, &val, NULL );
                is_default_output_set = true;
            }
            msg_Dbg( p_aout, "device supports 5 channels" );
        }
    }

    /* Test for 2 Front 2 Rear support */
    i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT |
                          AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
    if( ( p_aout->format.i_physical_channels & i_physical_channels )
        == i_physical_channels )
    {
        if( CreateDSBufferPCM( p_aout, &i_format, i_physical_channels, 4,
                               p_aout->format.i_rate, true )
            == VLC_SUCCESS )
        {
            val.i_int = AOUT_VAR_2F2R;
            text.psz_string = _("2 Front 2 Rear");
            var_Change( p_aout, "audio-device",
                        VLC_VAR_ADDCHOICE, &val, &text );
            if(!is_default_output_set)
            {
                var_Change( p_aout, "audio-device", VLC_VAR_SETDEFAULT, &val, NULL );
                is_default_output_set = true;
            }
            msg_Dbg( p_aout, "device supports 4 channels" );
        }
    }

    /* Test for stereo support */
    i_physical_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
    if( CreateDSBufferPCM( p_aout, &i_format, i_physical_channels, 2,
                           p_aout->format.i_rate, true )
        == VLC_SUCCESS )
    {
        val.i_int = AOUT_VAR_STEREO;
        text.psz_string = _("Stereo");
        var_Change( p_aout, "audio-device", VLC_VAR_ADDCHOICE, &val, &text );
        if(!is_default_output_set)
        {
            var_Change( p_aout, "audio-device", VLC_VAR_SETDEFAULT, &val, NULL );
            is_default_output_set = true;
            msg_Dbg( p_aout, "device supports 2 channels (DEFAULT!)" );
        }
        else msg_Dbg( p_aout, "device supports 2 channels" );
    }

    /* Test for mono support */
    i_physical_channels = AOUT_CHAN_CENTER;
    if( CreateDSBufferPCM( p_aout, &i_format, i_physical_channels, 1,
                           p_aout->format.i_rate, true )
        == VLC_SUCCESS )
    {
        val.i_int = AOUT_VAR_MONO;
        text.psz_string = _("Mono");
        var_Change( p_aout, "audio-device", VLC_VAR_ADDCHOICE, &val, &text );
        msg_Dbg( p_aout, "device supports 1 channel" );
    }

    /* Check the speaker configuration to determine which channel config should
     * be the default */
    if FAILED( IDirectSound_GetSpeakerConfig( p_aout->sys->p_dsobject,
                                              &ui_speaker_config ) )
    {
        ui_speaker_config = DSSPEAKER_STEREO;
        msg_Dbg( p_aout, "GetSpeakerConfig failed" );
    }
    switch( DSSPEAKER_CONFIG(ui_speaker_config) )
    {
    case DSSPEAKER_7POINT1:
        msg_Dbg( p_aout, "Windows says your SpeakerConfig is 7.1" );
        val.i_int = AOUT_VAR_7_1;
        break;
    case DSSPEAKER_5POINT1:
        msg_Dbg( p_aout, "Windows says your SpeakerConfig is 5.1" );
        val.i_int = AOUT_VAR_5_1;
        break;
    case DSSPEAKER_QUAD:
        msg_Dbg( p_aout, "Windows says your SpeakerConfig is Quad" );
        val.i_int = AOUT_VAR_2F2R;
        break;
#if 0 /* Lots of people just get their settings wrong and complain that
       * this is a problem with VLC so just don't ever set mono by default. */
    case DSSPEAKER_MONO:
        val.i_int = AOUT_VAR_MONO;
        break;
#endif
    case DSSPEAKER_SURROUND:
        msg_Dbg( p_aout, "Windows says your SpeakerConfig is surround" );
    case DSSPEAKER_STEREO:
        msg_Dbg( p_aout, "Windows says your SpeakerConfig is stereo" );
    default:
        /* If nothing else is found, choose stereo output */
        val.i_int = AOUT_VAR_STEREO;
        break;
    }

    /* Check if we want to override speaker config */
    switch( p_aout->sys->i_speaker_setup )
    {
    case 0: /* Default value aka Windows default speaker setup */
        break;
    case 1: /* Mono */
        msg_Dbg( p_aout, "SpeakerConfig is forced to Mono" );
        val.i_int = AOUT_VAR_MONO;
        break;
    case 2: /* Stereo */
        msg_Dbg( p_aout, "SpeakerConfig is forced to Stereo" );
        val.i_int = AOUT_VAR_STEREO;
        break;
    case 3: /* Quad */
        msg_Dbg( p_aout, "SpeakerConfig is forced to Quad" );
        val.i_int = AOUT_VAR_2F2R;
        break;
    case 4: /* 5.1 */
        msg_Dbg( p_aout, "SpeakerConfig is forced to 5.1" );
        val.i_int = AOUT_VAR_5_1;
        break;
    case 5: /* 7.1 */
        msg_Dbg( p_aout, "SpeakerConfig is forced to 7.1" );
        val.i_int = AOUT_VAR_7_1;
        break;
    default:
        msg_Dbg( p_aout, "SpeakerConfig is forced to non-existing value" );
        break;
    }

    var_Set( p_aout, "audio-device", val );

    /* Test for SPDIF support */
    if ( AOUT_FMT_NON_LINEAR( &p_aout->format ) )
    {
        if( CreateDSBuffer( p_aout, VLC_CODEC_SPDIFL,
                            p_aout->format.i_physical_channels,
                            aout_FormatNbChannels( &p_aout->format ),
                            p_aout->format.i_rate,
                            AOUT_SPDIF_SIZE, true )
            == VLC_SUCCESS )
        {
            msg_Dbg( p_aout, "device supports A/52 over S/PDIF" );
            val.i_int = AOUT_VAR_SPDIF;
            text.psz_string = _("A/52 over S/PDIF");
            var_Change( p_aout, "audio-device",
                        VLC_VAR_ADDCHOICE, &val, &text );
            if( var_InheritBool( p_aout, "spdif" ) )
                var_Set( p_aout, "audio-device", val );
        }
    }

    var_Change( p_aout, "audio-device", VLC_VAR_CHOICESCOUNT, &val, NULL );
    if( val.i_int <= 0 )
    {
        /* Probe() has failed. */
        var_Destroy( p_aout, "audio-device" );
        return;
    }

    var_AddCallback( p_aout, "audio-device", aout_ChannelsRestart, NULL );
    var_TriggerCallback( p_aout, "intf-change" );
}

/*****************************************************************************
 * Play: we'll start playing the directsound buffer here because at least here
 *       we know the first buffer has been put in the aout fifo and we also
 *       know its date.
 *****************************************************************************/
static void Play( audio_output_t *p_aout )
{
    if( !p_aout->sys->b_playing )
    {
        aout_buffer_t *p_buffer;

        p_aout->sys->b_playing = 1;

        /* get the playing date of the first aout buffer */
        p_aout->sys->p_notif->start_date =
            aout_FifoFirstDate( &p_aout->fifo );

        /* fill in the first samples */
        for( int i = 0; i < FRAMES_NUM; i++ )
        {
            p_buffer = aout_FifoPop( &p_aout->fifo );
            if( !p_buffer ) break;
            FillBuffer( p_aout, i, p_buffer );
        }

        /* wake up the audio output thread */
        SetEvent( p_aout->sys->p_notif->event );
    }
}

/*****************************************************************************
 * CloseAudio: close the audio device
 *****************************************************************************/
static void CloseAudio( vlc_object_t *p_this )
{
    audio_output_t * p_aout = (audio_output_t *)p_this;
    aout_sys_t *p_sys = p_aout->sys;

    msg_Dbg( p_aout, "closing audio device" );

    /* kill the position notification thread, if any */
    if( p_sys->p_notif )
    {
        vlc_atomic_set(&p_aout->sys->p_notif->abort, 1);
        /* wake up the audio thread if needed */
        if( !p_sys->b_playing ) SetEvent( p_sys->p_notif->event );

        vlc_join( p_sys->p_notif->thread, NULL );
        free( p_sys->p_notif );
    }

    /* release the secondary buffer */
    DestroyDSBuffer( p_aout );

    /* finally release the DirectSound object */
    if( p_sys->p_dsobject ) IDirectSound_Release( p_sys->p_dsobject );

    /* free DSOUND.DLL */
    if( p_sys->hdsound_dll ) FreeLibrary( p_sys->hdsound_dll );

    free( p_aout->sys->p_device_guid );
    free( p_sys );
}

/*****************************************************************************
 * CallBackDirectSoundEnum: callback to enumerate available devices
 *****************************************************************************/
static int CALLBACK CallBackDirectSoundEnum( LPGUID p_guid, LPCWSTR psz_desc,
                                             LPCWSTR psz_mod, LPVOID _p_aout )
{
    VLC_UNUSED( psz_mod );

    audio_output_t *p_aout = (audio_output_t *)_p_aout;

    char *psz_device = FromWide( psz_desc );
    msg_Dbg( p_aout, "found device: %s", psz_device );

    if( p_aout->sys->psz_device &&
        !strcmp(p_aout->sys->psz_device, psz_device) && p_guid )
    {
        /* Use the device corresponding to psz_device */
        p_aout->sys->p_device_guid = malloc( sizeof( GUID ) );
        *p_aout->sys->p_device_guid = *p_guid;
        msg_Dbg( p_aout, "using device: %s", psz_device );
    }
    else
    {
        /* If no default device has been selected, chose the first one */
        if( !p_aout->sys->psz_device && p_guid )
        {
            p_aout->sys->psz_device = strdup( psz_device );
            p_aout->sys->p_device_guid = malloc( sizeof( GUID ) );
            *p_aout->sys->p_device_guid = *p_guid;
            msg_Dbg( p_aout, "using device: %s", psz_device );
        }
    }

    free( psz_device );
    return true;
}

/*****************************************************************************
 * InitDirectSound: handle all the gory details of DirectSound initialisation
 *****************************************************************************/
static int InitDirectSound( audio_output_t *p_aout )
{
    HRESULT (WINAPI *OurDirectSoundCreate)(LPGUID, LPDIRECTSOUND *, LPUNKNOWN);
    HRESULT (WINAPI *OurDirectSoundEnumerate)(LPDSENUMCALLBACKW, LPVOID);

    p_aout->sys->hdsound_dll = LoadLibrary("DSOUND.DLL");
    if( p_aout->sys->hdsound_dll == NULL )
    {
        msg_Warn( p_aout, "cannot open DSOUND.DLL" );
        goto error;
    }

    OurDirectSoundCreate = (void *)
        GetProcAddress( p_aout->sys->hdsound_dll,
                        "DirectSoundCreate" );
    if( OurDirectSoundCreate == NULL )
    {
        msg_Warn( p_aout, "GetProcAddress FAILED" );
        goto error;
    }

    /* Get DirectSoundEnumerate */
    OurDirectSoundEnumerate = (void *)
       GetProcAddress( p_aout->sys->hdsound_dll,
                       "DirectSoundEnumerateW" );
    if( OurDirectSoundEnumerate )
    {
        p_aout->sys->psz_device = var_InheritString(p_aout, "directx-audio-device-name");
        /* Attempt enumeration */
        if( FAILED( OurDirectSoundEnumerate( CallBackDirectSoundEnum,
                                             p_aout ) ) )
        {
            msg_Dbg( p_aout, "enumeration of DirectSound devices failed" );
        }
    }

    /* Create the direct sound object */
    if FAILED( OurDirectSoundCreate( p_aout->sys->p_device_guid,
                                     &p_aout->sys->p_dsobject,
                                     NULL ) )
    {
        msg_Warn( p_aout, "cannot create a direct sound device" );
        goto error;
    }

    /* Set DirectSound Cooperative level, ie what control we want over Windows
     * sound device. In our case, DSSCL_EXCLUSIVE means that we can modify the
     * settings of the primary buffer, but also that only the sound of our
     * application will be hearable when it will have the focus.
     * !!! (this is not really working as intended yet because to set the
     * cooperative level you need the window handle of your application, and
     * I don't know of any easy way to get it. Especially since we might play
     * sound without any video, and so what window handle should we use ???
     * The hack for now is to use the Desktop window handle - it seems to be
     * working */
    if( IDirectSound_SetCooperativeLevel( p_aout->sys->p_dsobject,
                                          GetDesktopWindow(),
                                          DSSCL_EXCLUSIVE) )
    {
        msg_Warn( p_aout, "cannot set direct sound cooperative level" );
    }

    return VLC_SUCCESS;

 error:
    p_aout->sys->p_dsobject = NULL;
    if( p_aout->sys->hdsound_dll )
    {
        FreeLibrary( p_aout->sys->hdsound_dll );
        p_aout->sys->hdsound_dll = NULL;
    }
    return VLC_EGENERIC;

}

/*****************************************************************************
 * CreateDSBuffer: Creates a direct sound buffer of the required format.
 *****************************************************************************
 * This function creates the buffer we'll use to play audio.
 * In DirectSound there are two kinds of buffers:
 * - the primary buffer: which is the actual buffer that the soundcard plays
 * - the secondary buffer(s): these buffers are the one actually used by
 *    applications and DirectSound takes care of mixing them into the primary.
 *
 * Once you create a secondary buffer, you cannot change its format anymore so
 * you have to release the current one and create another.
 *****************************************************************************/
static int CreateDSBuffer( audio_output_t *p_aout, int i_format,
                           int i_channels, int i_nb_channels, int i_rate,
                           int i_bytes_per_frame, bool b_probe )
{
    WAVEFORMATEXTENSIBLE waveformat;
    DSBUFFERDESC         dsbdesc;
    unsigned int         i;

    /* First set the sound buffer format */
    waveformat.dwChannelMask = 0;
    for( i = 0; i < sizeof(pi_channels_src)/sizeof(uint32_t); i++ )
    {
        if( i_channels & pi_channels_src[i] )
            waveformat.dwChannelMask |= pi_channels_in[i];
    }

    switch( i_format )
    {
    case VLC_CODEC_SPDIFL:
        i_nb_channels = 2;
        /* To prevent channel re-ordering */
        waveformat.dwChannelMask = SPEAKER_FRONT_LEFT | SPEAKER_FRONT_RIGHT;
        waveformat.Format.wBitsPerSample = 16;
        waveformat.Samples.wValidBitsPerSample =
            waveformat.Format.wBitsPerSample;
        waveformat.Format.wFormatTag = WAVE_FORMAT_DOLBY_AC3_SPDIF;
        waveformat.