/*****************************************************************************
 * directx.c: Windows DirectX audio output method
 *****************************************************************************
 * Copyright (C) 2001-2009 the VideoLAN team
 * $Id: 23cfe0af5f64e72fb448eeaf1f0dfb51450f7d43 $
 *
 * 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 "windows_audio_common.h"

#include <dsound.h>

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

/*****************************************************************************
 * notification_thread_t: DirectX event thread
 *****************************************************************************/
typedef struct notification_thread_t
{
    VLC_COMMON_MEMBERS

    aout_instance_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;

} 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       ( aout_instance_t * );

/* local functions */
static void Probe             ( aout_instance_t * );
static int  InitDirectSound   ( aout_instance_t * );
static int  CreateDSBuffer    ( aout_instance_t *, int, int, int, int, int, bool );
static int  CreateDSBufferPCM ( aout_instance_t *, vlc_fourcc_t*, int, int, int, bool );
static void DestroyDSBuffer   ( aout_instance_t * );
static void* DirectSoundThread( vlc_object_t * );
static int  FillBuffer        ( aout_instance_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" )
    add_shortcut( "directsound" )

    add_string( "directx-audio-device-name", "default", NULL,
             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") )
        change_need_restart ()
    add_bool( "directx-audio-float32", false, NULL, FLOAT_TEXT,
              FLOAT_LONGTEXT, true )
    add_string( "directx-audio-speaker", "Windows default", NULL,
                 SPEAKER_TEXT, SPEAKER_LONGTEXT, true )
        change_string_list( speaker_list, 0, 0 )
        change_need_restart ()

    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 )
{
    aout_instance_t * p_aout = (aout_instance_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->output.p_sys = malloc( sizeof( aout_sys_t ) );
    if( p_aout->output.p_sys == NULL )
        return VLC_ENOMEM;

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

    p_aout->output.pf_play = Play;
    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->output.p_sys->i_speaker_setup = i;

    p_aout->output.p_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->output.output.i_format = VLC_CODEC_SPDIFL;

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

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

        aout_VolumeNoneInit( p_aout );
    }
    else
    {
        if( val.i_int == AOUT_VAR_5_1 )
        {
            p_aout->output.output.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->output.output.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->output.output.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->output.output.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->output.output.i_physical_channels = AOUT_CHAN_CENTER;
        }
        else
        {
            p_aout->output.output.i_physical_channels
                = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
        }

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

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

    /* Now we need to setup our DirectSound play notification structure */
    p_aout->output.p_sys->p_notif =
        vlc_object_create( p_aout, sizeof(notification_thread_t) );
    p_aout->output.p_sys->p_notif->p_aout = p_aout;

    p_aout->output.p_sys->p_notif->event = CreateEvent( 0, FALSE, FALSE, 0 );
    p_aout->output.p_sys->p_notif->i_frame_size =
        p_aout->output.p_sys->i_frame_size;

    /* then launch the notification thread */
    msg_Dbg( p_aout, "creating DirectSoundThread" );
    if( vlc_thread_create( p_aout->output.p_sys->p_notif,
                           "DirectSound Notification Thread",
                           DirectSoundThread,
                           VLC_THREAD_PRIORITY_HIGHEST ) )
    {
        msg_Err( p_aout, "cannot create DirectSoundThread" );
        CloseHandle( p_aout->output.p_sys->p_notif->event );
        vlc_object_release( p_aout->output.p_sys->p_notif );
        p_aout->output.p_sys->p_notif = NULL;
        goto error;
    }

    vlc_object_attach( p_aout->output.p_sys->p_notif, p_aout );

    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( aout_instance_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->output.output.i_physical_channels == i_physical_channels )
    {
        if( CreateDSBufferPCM( p_aout, &i_format, i_physical_channels, 6,
                               p_aout->output.output.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->output.output.i_physical_channels == i_physical_channels )
    {
        if( CreateDSBufferPCM( p_aout, &i_format, i_physical_channels, 8,
                                  p_aout->output.output.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->output.output.i_physical_channels == i_physical_channels )
    {
        if( CreateDSBufferPCM( p_aout, &i_format, i_physical_channels, 5,
                               p_aout->output.output.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->output.output.i_physical_channels & i_physical_channels )
        == i_physical_channels )
    {
        if( CreateDSBufferPCM( p_aout, &i_format, i_physical_channels, 4,
                               p_aout->output.output.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->output.output.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->output.output.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->output.p_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->output.p_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->output.output ) )
    {
        if( CreateDSBuffer( p_aout, VLC_CODEC_SPDIFL,
                            p_aout->output.output.i_physical_channels,
                            aout_FormatNbChannels( &p_aout->output.output ),
                            p_aout->output.output.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_SetBool( p_aout, "intf-change", true );
}

/*****************************************************************************
 * 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( aout_instance_t *p_aout )
{
    if( !p_aout->output.p_sys->b_playing )
    {
        aout_buffer_t *p_buffer;

        p_aout->output.p_sys->b_playing = 1;

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

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

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

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

    msg_Dbg( p_aout, "closing audio device" );

    /* kill the position notification thread, if any */
    if( p_sys->p_notif )
    {
        vlc_object_kill( p_sys->p_notif );
        /* wake up the audio thread if needed */
        if( !p_sys->b_playing ) SetEvent( p_sys->p_notif->event );

        vlc_thread_join( p_sys->p_notif );
        vlc_object_release( 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->output.p_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 );

    aout_instance_t *p_aout = (aout_instance_t *)_p_aout;

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

    if( p_aout->output.p_sys->psz_device &&
        !strcmp(p_aout->output.p_sys->psz_device, psz_device) && p_guid )
    {
        /* Use the device corresponding to psz_device */
        p_aout->output.p_sys->p_device_guid = malloc( sizeof( GUID ) );
        *p_aout->output.p_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->output.p_sys->psz_device && p_guid )
        {
            p_aout->output.p_sys->psz_device = strdup( psz_device );
            p_aout->output.p_sys->p_device_guid = malloc( sizeof( GUID ) );
            *p_aout->output.p_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( aout_instance_t *p_aout )
{
    HRESULT (WINAPI *OurDirectSoundCreate)(LPGUID, LPDIRECTSOUND *, LPUNKNOWN);
    HRESULT (WINAPI *OurDirectSoundEnumerate)(LPDSENUMCALLBACKW, LPVOID);

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

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

    /* Get DirectSoundEnumerate */
    OurDirectSoundEnumerate = (void *)
       GetProcAddress( p_aout->output.p_sys->hdsound_dll,
                       "DirectSoundEnumerateW" );
    if( OurDirectSoundEnumerate )
    {
        p_aout->output.p_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->output.p_sys->p_device_guid,
                                     &p_aout->output.p_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->output.p_sys->p_dsobject,
                                          GetDesktopWindow(),
                                          DSSCL_EXCLUSIVE) )
    {
        msg_Warn( p_aout, "cannot set direct sound cooperative level" );
    }

    return VLC_SUCCESS;

 error:
    p_aout->output.p_sys->p_dsobject = NULL;
    if( p_aout->output.p_sys->hdsound_dll )
    {
        FreeLibrary( p_aout->output.p_sys->hdsound_dll );
        p_aout->output.p_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( aout_instance_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.SubFormat = _KSDATAFORMAT_SUBTYPE_DOLBY_AC3_SPDIF;
        break;

    case VLC_CODEC_FL32:
        waveformat.Format.wBitsPerSample = sizeof(float) * 8;
        waveformat.Samples.wValidBitsPerSample =
            waveformat.Format.wBitsPerSample;
        waveformat.Format.wFormatTag = WAVE_FORMAT_IEEE_FLOAT;
        waveformat.SubFormat = _KSDATAFORMAT_SUBTYPE_IEEE_FLOAT;
        break;

    case VLC_CODEC_S16L:
        waveformat.Format.wBitsPerSample = 16;
        waveformat.Samples.wValidBitsPerSample =
            waveformat.Format.wBitsPerSample;
        waveformat.Format.wFormatTag = WAVE_FORMAT_PCM;
        waveformat.SubFormat = _KSDATAFORMAT_SUBTYPE_PCM;
        break;
    }

    waveformat.Format.nChannels = i_nb_channels;
    waveformat.Format.nSamplesPerSec = i_rate;
    waveformat.Format.nBlockAlign =
        waveformat.Format.wBitsPerSample / 8 * i_nb_channels;
    waveformat.Format.nAvgBytesPerSec =
        waveformat.Format.nSamplesPerSec * waveformat.Format.nBlockAlign;

    p_aout->output.p_sys->i_bits_per_sample = waveformat.Format.wBitsPerSample;
    p_aout->output.p_sys->i_channels = i_nb_channels;

    /* Then fill in the direct sound descriptor */
    memset(&dsbdesc, 0, sizeof(DSBUFFERDESC));
    dsbdesc.dwSize = sizeof(DSBUFFERDESC);
    dsbdesc.dwFlags = DSBCAPS_GETCURRENTPOSITION2/* Better position accuracy */
                    | DSBCAPS_GLOBALFOCUS;      /* Allows background playing */

    /* Only use the new WAVE_FORMAT_EXTENSIBLE format for multichannel audio */
    if( i_nb_channels <= 2 )
    {
        waveformat.Format.cbSize = 0;
    }
    else
    {
        waveformat.Format.wFormatTag = WAVE_FORMAT_EXTENSIBLE;
        waveformat.Format.cbSize =
            sizeof(WAVEFORMATEXTENSIBLE) - sizeof(WAVEFORMATEX);

        /* Needed for 5.1 on emu101k */
        dsbdesc.dwFlags |= DSBCAPS_LOCHARDWARE;
    }

    dsbdesc.dwBufferBytes = FRAMES_NUM * i_bytes_per_frame;   /* buffer size */
    dsbdesc.lpwfxFormat = (WAVEFORMATEX *)&waveformat;

    if FAILED( IDirectSound_CreateSoundBuffer(
                   p_aout->output.p_sys->p_dsobject, &dsbdesc,
                   &p_aout->output.p_sys->p_dsbuffer, NULL) )
    {
        if( dsbdesc.dwFlags & DSBCAPS_LOCHARDWARE )
        {
            /* Try without DSBCAPS_LOCHARDWARE */
            dsbdesc.dwFlags &= ~DSBCAPS_LOCHARDWARE;
            if FAILED( IDirectSound_CreateSoundBuffer(
                   p_aout->output.p_sys->p_dsobject, &dsbdesc,
                   &p_aout->output.p_sys->p_dsbuffer, NULL) )
            {
                return VLC_EGENERIC;
            }
            if( !b_probe )
                msg_Dbg( p_aout, "couldn't use hardware sound buffer" );
        }
        else
        {
            return VLC_EGENERIC;
        }
    }

    /* Stop here if we were just probing */
    if( b_probe )
    {
        IDirectSoundBuffer_Release( p_aout->output.p_sys->p_dsbuffer );
        p_aout->output.p_sys->p_dsbuffer = NULL;
        return VLC_SUCCESS;
    }

    p_aout->output.p_sys->i_frame_size = i_bytes_per_frame;
    p_aout->output.p_sys->i_channel_mask = waveformat.dwChannelMask;
    p_aout->output.p_sys->b_chan_reorder =
        aout_CheckChannelReorder( pi_channels_in, pi_channels_out,
                                  waveformat.dwChannelMask, i_nb_channels,
                                  p_aout->output.p_sys->pi_chan_table );

    if( p_aout->output.p_sys->b_chan_reorder )
    {
        msg_Dbg( p_aout, "channel reordering needed" );
    }

    return VLC_SUCCESS;
}

/*****************************************************************************
 * CreateDSBufferPCM: creates a PCM direct sound buffer.
 *****************************************************************************
 * We first try to create a WAVE_FORMAT_IEEE_FLOAT buffer if supported by
 * the hardware, otherwise we create a WAVE_FORMAT_PCM buffer.
 ****************************************************************************/
static int CreateDSBufferPCM( aout_instance_t *p_aout, vlc_fourcc_t *i_format,
                              int i_channels, int i_nb_channels, int i_rate,
                              bool b_probe )
{
    /* Float32 audio samples are not supported for 5.1 output on the emu101k */
    if( !var_GetBool( p_aout, "directx-audio-float32" ) ||
        i_nb_channels > 2 ||
        CreateDSBuffer( p_aout, VLC_CODEC_FL32,
                        i_channels, i_nb_channels, i_rate,
                        FRAME_SIZE * 4 * i_nb_channels, b_probe )
        != VLC_SUCCESS )
    {
        if ( CreateDSBuffer( p_aout, VLC_CODEC_S16L,
                             i_channels, i_nb_channels, i_rate,
                             FRAME_SIZE * 2 * i_nb_channels, b_probe )
             != VLC_SUCCESS )
        {
            return VLC_EGENERIC;
        }
        else
        {
            *i_format = VLC_CODEC_S16L;
            return VLC_SUCCESS;
        }
    }
    else
    {
        *i_format = VLC_CODEC_FL32;
        return VLC_SUCCESS;
    }
}

/*****************************************************************************
 * DestroyDSBuffer
 *****************************************************************************
 * This function destroys the secondary buffer.
 *****************************************************************************/
static void DestroyDSBuffer( aout_instance_t *p_aout )
{
    if( p_aout->output.p_sys->p_dsbuffer )
    {
        IDirectSoundBuffer_Release( p_aout->output.p_sys->p_dsbuffer );
        p_aout->output.p_sys->p_dsbuffer = NULL;
    }
}

/*****************************************************************************
 * FillBuffer: Fill in one of the direct sound frame buffers.
 *****************************************************************************
 * Returns VLC_SUCCESS on success.
 *****************************************************************************/
static int FillBuffer( aout_instance_t *p_aout, int i_frame,
                       aout_buffer_t *p_buffer )
{
    notification_thread_t *p_notif = p_aout->output.p_sys->p_notif;
    aout_sys_t *p_sys = p_aout->output.p_sys;
    void *p_write_position, *p_wrap_around;
    unsigned long l_bytes1, l_bytes2;
    HRESULT dsresult;

    /* Before copying anything, we have to lock the buffer */
    dsresult = IDirectSoundBuffer_Lock(
                p_sys->p_dsbuffer,                              /* DS buffer */
                i_frame * p_notif->i_frame_size,             /* Start offset */
                p_notif->i_frame_size,                    /* Number of bytes */
                &p_write_position,                  /* Address of lock start */
                &l_bytes1,       /* Count of bytes locked before wrap around */
                &p_wrap_around,           /* Buffer address (if wrap around) */
                &l_bytes2,               /* Count of bytes after wrap around */
                0 );                                                /* Flags */
    if( dsresult == DSERR_BUFFERLOST )
    {
        IDirectSoundBuffer_Restore( p_sys->p_dsbuffer );
        dsresult = IDirectSoundBuffer_Lock(
                               p_sys->p_dsbuffer,
                               i_frame * p_notif->i_frame_size,
                               p_notif->i_frame_size,
                               &p_write_position,
                               &l_bytes1,
                               &p_wrap_around,
                               &l_bytes2,
                               0 );
    }
    if( dsresult != DS_OK )
    {
        msg_Warn( p_notif, "cannot lock buffer" );
        if( p_buffer ) aout_BufferFree( p_buffer );
        return VLC_EGENERIC;
    }

    if( p_buffer == NULL )
    {
        memset( p_write_position, 0, l_bytes1 );
    }
    else
    {
        if( p_sys->b_chan_reorder )
        {
            /* Do the channel reordering here */
            aout_ChannelReorder( p_buffer->p_buffer, p_buffer->i_buffer,
                                 p_sys->i_channels, p_sys->pi_chan_table,
                                 p_sys->i_bits_per_sample );
        }

        vlc_memcpy( p_write_position, p_buffer->p_buffer, l_bytes1 );
        aout_BufferFree( p_buffer );
    }

    /* Now the data has been copied, unlock the buffer */
    IDirectSoundBuffer_Unlock( p_sys->p_dsbuffer, p_write_position, l_bytes1,
                               p_wrap_around, l_bytes2 );

    p_notif->i_write_slot = (i_frame + 1) % FRAMES_NUM;
    return VLC_SUCCESS;
}

/*****************************************************************************
 * DirectSoundThread: this thread will capture play notification events.
 *****************************************************************************
 * We use this thread to emulate a callback mechanism. The thread probes for
 * event notification and fills up the DS secondary buffer when needed.
 *****************************************************************************/
static void* DirectSoundThread( vlc_object_t *p_this )
{
    notification_thread_t *p_notif = (notification_thread_t*)p_this;
    aout_instance_t *p_aout = p_notif->p_aout;
    mtime_t last_time;
    int canc = vlc_savecancel ();

    /* We don't want any resampling when using S/PDIF output */
    bool b_sleek = (p_aout->output.output.i_format == VLC_CODEC_SPDIFL);

    msg_Dbg( p_notif, "DirectSoundThread ready" );

    /* Wait here until Play() is called */
    WaitForSingleObject( p_notif->event, INFINITE );

    if( vlc_object_alive (p_notif) )
    {
        HRESULT dsresult;
        mwait( p_notif->start_date - AOUT_PTS_TOLERANCE / 2 );

        /* start playing the buffer */
        dsresult = IDirectSoundBuffer_Play( p_aout->output.p_sys->p_dsbuffer,
                                        0,                         /* Unused */
                                        0,                         /* Unused */
                                        DSBPLAY_LOOPING );          /* Flags */
        if( dsresult == DSERR_BUFFERLOST )
        {
            IDirectSoundBuffer_Restore( p_aout->output.p_sys->p_dsbuffer );
            dsresult = IDirectSoundBuffer_Play(
                                            p_aout->output.p_sys->p_dsbuffer,
                                            0,                     /* Unused */
                                            0,                     /* Unused */
                                            DSBPLAY_LOOPING );      /* Flags */
        }
        if( dsresult != DS_OK )
        {
            msg_Err( p_aout, "cannot start playing buffer" );
        }
    }
    last_time = mdate();

    while( vlc_object_alive (p_notif) )
    {
        DWORD l_read;
        int l_queued = 0, l_free_slots;
        unsigned i_frame_siz = p_aout->output.i_nb_samples;
        mtime_t mtime = mdate();
        int i;

        /*
         * Fill in as much audio data as we can in our circular buffer
         */

        /* Find out current play position */
        if FAILED( IDirectSoundBuffer_GetCurrentPosition(
                   p_aout->output.p_sys->p_dsbuffer, &l_read, NULL ) )
        {
            msg_Err( p_aout, "GetCurrentPosition() failed!" );
            l_read = 0;
        }

        /* Detect underruns */
        if( l_queued && mtime - last_time >
            INT64_C(1000000) * l_queued / p_aout->output.output.i_rate )
        {
            msg_Dbg( p_aout, "detected underrun!" );
        }
        last_time = mtime;

        /* Try to fill in as many frame buffers as possible */
        l_read /= (p_aout->output.output.i_bytes_per_frame /
            p_aout->output.output.i_frame_length);
        l_queued = p_notif->i_write_slot * i_frame_siz - l_read;
        if( l_queued < 0 ) l_queued += (i_frame_siz * FRAMES_NUM);
        l_free_slots = (FRAMES_NUM * i_frame_siz - l_queued) / i_frame_siz;

        for( i = 0; i < l_free_slots; i++ )
        {
            aout_buffer_t *p_buffer = aout_OutputNextBuffer( p_aout,
                mtime + INT64_C(1000000) * (i * i_frame_siz + l_queued) /
                p_aout->output.output.i_rate, b_sleek );

            /* If there is no audio data available and we have some buffered
             * already, then just wait for the next time */
            if( !p_buffer && (i || l_queued / i_frame_siz) ) break;

            if( FillBuffer( p_aout, p_notif->i_write_slot % FRAMES_NUM,
                            p_buffer ) != VLC_SUCCESS ) break;
        }

        /* Sleep a reasonable amount of time */
        l_queued += (i * i_frame_siz);
        msleep( INT64_C(1000000) * l_queued / p_aout->output.output.i_rate / 2 );
    }

    /* make sure the buffer isn't playing */
    IDirectSoundBuffer_Stop( p_aout->output.p_sys->p_dsbuffer );

    /* free the event */
    CloseHandle( p_notif->event );

    vlc_restorecancel (canc);
    msg_Dbg( p_notif, "DirectSoundThread exiting" );
    return NULL;
}

/*****************************************************************************
 * CallBackConfigNBEnum: callback to get the number of available devices
 *****************************************************************************/
static int CALLBACK CallBackConfigNBEnum( LPGUID p_guid, LPCWSTR psz_desc,
                                             LPCWSTR psz_mod, LPVOID p_nb )
{
    VLC_UNUSED( psz_mod ); VLC_UNUSED( psz_desc ); VLC_UNUSED( p_guid );

    int * a = (int *)p_nb;
    (*a)++;
    return true;
}

/*****************************************************************************
 * CallBackConfigEnum: callback to add available devices to the preferences list
 *****************************************************************************/
static int CALLBACK CallBackConfigEnum( LPGUID p_guid, LPCWSTR psz_desc,
                                             LPCWSTR psz_mod, LPVOID _p_item )
{
    VLC_UNUSED( psz_mod ); VLC_UNUSED( p_guid );

    module_config_t *p_item = (module_config_t *) _p_item;

    p_item->ppsz_list[p_item->i_list] = FromWide( psz_desc );
    p_item->ppsz_list_text[p_item->i_list] = FromWide( psz_desc );
    p_item->i_list++;
    return true;
}

/*****************************************************************************
 * ReloadDirectXDevices: store the list of devices in preferences
 *****************************************************************************/
static int ReloadDirectXDevices( vlc_object_t *p_this, char const *psz_name,
                                 vlc_value_t newval, vlc_value_t oldval, void *data )
{
    VLC_UNUSED( newval ); VLC_UNUSED( oldval ); VLC_UNUSED( data );

    module_config_t *p_item = config_FindConfig( p_this, psz_name );
    if( !p_item ) return VLC_SUCCESS;

    /* Clear-up the current list */
    if( p_item->i_list )
    {
        for( int i = 0; i < p_item->i_list; i++ )
        {
            free((char *)(p_item->ppsz_list[i]) );
            free((char *)(p_item->ppsz_list_text[i]) );
        }
    }

    HRESULT (WINAPI *OurDirectSoundEnumerate)(LPDSENUMCALLBACKW, LPVOID);

    HANDLE hdsound_dll = LoadLibrary("DSOUND.DLL");
    if( hdsound_dll == NULL )
    {
        msg_Warn( p_this, "cannot open DSOUND.DLL" );
        return VLC_SUCCESS;
    }

    /* Get DirectSoundEnumerate */
    OurDirectSoundEnumerate = (void *)
                    GetProcAddress( hdsound_dll, "DirectSoundEnumerateW" );

    if( OurDirectSoundEnumerate == NULL )
        goto error;

    int nb_devices = 0;
    OurDirectSoundEnumerate(CallBackConfigNBEnum, &nb_devices);
    msg_Dbg(p_this,"found %d devices", nb_devices);

    p_item->ppsz_list = xrealloc( p_item->ppsz_list,
                                  nb_devices * sizeof(char *) );
    p_item->ppsz_list_text = xrealloc( p_item->ppsz_list_text,
                                  nb_devices * sizeof(char *) );

    p_item->i_list = 0;
    OurDirectSoundEnumerate(CallBackConfigEnum, p_item);

    /* Signal change to the interface */
    p_item->b_dirty = true;

error:
    FreeLibrary(hdsound_dll);

    return VLC_SUCCESS;
}

