+/*****************************************************************************
+ * dolby.c : simple decoder for dolby surround encoded streams
+ *****************************************************************************
+ * Copyright (C) 2005 the VideoLAN team
+ * $Id: headphone.c 11664 2005-07-09 06:17:09Z courmisch $
+ *
+ * Authors: Boris Dorès <babal@via.ecp.fr>
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Preamble
+ *****************************************************************************/
+#include <stdlib.h> /* malloc(), free() */
+#include <string.h>
+
+#include <vlc/vlc.h>
+#include "audio_output.h"
+#include "aout_internal.h"
+
+/*****************************************************************************
+ * Local prototypes
+ *****************************************************************************/
+static int Create ( vlc_object_t * );
+static void Destroy ( vlc_object_t * );
+
+static void DoWork ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
+ aout_buffer_t * );
+
+/*****************************************************************************
+ * Module descriptor
+ *****************************************************************************/
+vlc_module_begin();
+ set_description( N_("Simple decoder for dolby surround encoded streams") );
+ set_shortname( _("Dolby surround decoder") );
+ set_category( CAT_INPUT );
+ set_subcategory( SUBCAT_INPUT_ACODEC );
+ set_capability( "audio filter", 5 );
+ set_callbacks( Create, Destroy );
+vlc_module_end();
+
+/*****************************************************************************
+ * Internal data structures
+ *****************************************************************************/
+struct aout_filter_sys_t
+{
+ int i_left;
+ int i_center;
+ int i_right;
+ int i_rear_left;
+ int i_rear_center;
+ int i_rear_right;
+};
+
+/* our internal channel order (WG-4 order) */
+static const uint32_t pi_channels[] =
+{ AOUT_CHAN_LEFT, AOUT_CHAN_RIGHT, AOUT_CHAN_MIDDLELEFT, AOUT_CHAN_MIDDLERIGHT,
+ AOUT_CHAN_REARLEFT, AOUT_CHAN_REARRIGHT, AOUT_CHAN_REARCENTER,
+ AOUT_CHAN_CENTER, AOUT_CHAN_LFE, 0 };
+
+/*****************************************************************************
+ * Create: allocate headphone downmixer
+ *****************************************************************************/
+static int Create( vlc_object_t *p_this )
+{
+ int i = 0;
+ int i_offset = 0;
+ aout_filter_t * p_filter = (aout_filter_t *)p_this;
+
+ /* Validate audio filter format */
+ if ( p_filter->input.i_original_channels
+ != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT|AOUT_CHAN_DOLBYSTEREO )
+ || aout_FormatNbChannels( &p_filter->output ) <= 2
+ || p_filter->output.i_physical_channels
+ != ( p_filter->output.i_original_channels & AOUT_CHAN_PHYSMASK )
+ || p_filter->input.i_physical_channels
+ != ( p_filter->input.i_original_channels & AOUT_CHAN_PHYSMASK ))
+ {
+ return VLC_EGENERIC;
+ }
+
+ if ( p_filter->input.i_rate != p_filter->output.i_rate )
+ {
+ return VLC_EGENERIC;
+ }
+
+ if ( p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
+ || p_filter->output.i_format != VLC_FOURCC('f','l','3','2') )
+ {
+ return VLC_EGENERIC;
+ }
+
+ /* Allocate the memory needed to store the module's structure */
+ p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
+ if ( p_filter->p_sys == NULL )
+ {
+ msg_Err( p_filter, "Out of memory" );
+ return VLC_EGENERIC;
+ }
+ p_filter->p_sys->i_left = -1;
+ p_filter->p_sys->i_center = -1;
+ p_filter->p_sys->i_right = -1;
+ p_filter->p_sys->i_rear_left = -1;
+ p_filter->p_sys->i_rear_center = -1;
+ p_filter->p_sys->i_rear_right = -1;
+
+ while ( pi_channels[i] )
+ {
+ if ( p_filter->output.i_physical_channels & pi_channels[i] )
+ {
+ switch ( pi_channels[i] )
+ {
+ case AOUT_CHAN_LEFT:
+ p_filter->p_sys->i_left = i_offset;
+ break;
+ case AOUT_CHAN_CENTER:
+ p_filter->p_sys->i_center = i_offset;
+ break;
+ case AOUT_CHAN_RIGHT:
+ p_filter->p_sys->i_right = i_offset;
+ break;
+ case AOUT_CHAN_REARLEFT:
+ p_filter->p_sys->i_rear_left = i_offset;
+ break;
+ case AOUT_CHAN_REARCENTER:
+ p_filter->p_sys->i_rear_center = i_offset;
+ break;
+ case AOUT_CHAN_REARRIGHT:
+ p_filter->p_sys->i_rear_right = i_offset;
+ break;
+ }
+ ++i_offset;
+ }
+ ++i;
+ }
+
+ p_filter->pf_do_work = DoWork;
+ p_filter->b_in_place = 0;
+
+ return VLC_SUCCESS;
+}
+
+/*****************************************************************************
+ * Destroy: deallocate resources associated with headphone downmixer
+ *****************************************************************************/
+static void Destroy( vlc_object_t *p_this )
+{
+ aout_filter_t * p_filter = (aout_filter_t *)p_this;
+
+ if ( p_filter->p_sys != NULL )
+ {
+ free ( p_filter->p_sys );
+ p_filter->p_sys = NULL;
+ }
+}
+
+/*****************************************************************************
+ * DoWork: convert a buffer
+ *****************************************************************************/
+static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
+ aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
+{
+ float * p_in = (float*) p_in_buf->p_buffer;
+ float * p_out = (float*) p_out_buf->p_buffer;
+ size_t i_nb_samples = p_in_buf->i_nb_samples;
+ size_t i_nb_channels = aout_FormatNbChannels( &p_filter->output );
+
+ p_out_buf->i_nb_samples = i_nb_samples;
+ p_out_buf->i_nb_bytes = sizeof(float) * i_nb_samples
+ * aout_FormatNbChannels( &p_filter->output );
+ memset ( p_out , 0 , p_out_buf->i_nb_bytes );
+
+ if ( p_filter->p_sys != NULL )
+ {
+ struct aout_filter_sys_t * p_sys = p_filter->p_sys;
+ size_t i_nb_rear = 0;
+ size_t i;
+
+ if ( p_sys->i_rear_left >= 0 )
+ {
+ ++i_nb_rear;
+ }
+ if ( p_sys->i_rear_center >= 0 )
+ {
+ ++i_nb_rear;
+ }
+ if ( p_sys->i_rear_right >= 0 )
+ {
+ ++i_nb_rear;
+ }
+
+ for ( i = 0; i < i_nb_samples; ++i )
+ {
+ float f_left = p_in[ i * 2 ];
+ float f_right = p_in[ i * 2 + 1 ];
+ float f_rear = ( f_left - f_right ) / i_nb_rear;
+
+ if ( p_sys->i_center >= 0 )
+ {
+ float f_center = f_left + f_right;
+ f_left -= f_center / 2;
+ f_right -= f_center / 2;
+
+ p_out[ i * i_nb_channels + p_sys->i_center ] = f_center;
+ }
+
+ if ( p_sys->i_left >= 0 )
+ {
+ p_out[ i * i_nb_channels + p_sys->i_left ] = f_left;
+ }
+ if ( p_sys->i_right >= 0 )
+ {
+ p_out[ i * i_nb_channels + p_sys->i_right ] = f_right;
+ }
+ if ( p_sys->i_rear_left >= 0 )
+ {
+ p_out[ i * i_nb_channels + p_sys->i_rear_left ] = f_rear;
+ }
+ if ( p_sys->i_rear_center >= 0 )
+ {
+ p_out[ i * i_nb_channels + p_sys->i_rear_center ] = f_rear;
+ }
+ if ( p_sys->i_rear_right >= 0 )
+ {
+ p_out[ i * i_nb_channels + p_sys->i_rear_right ] = f_rear;
+ }
+ }
+ }
+}