--- /dev/null
+/*****************************************************************************
+ * simple.c : simple channel mixer plug-in (only 7/7.1/5/5.1 -> Stereo for now)
+ *****************************************************************************
+ * Copyright (C) 2002 VideoLAN
+ * $Id$
+ *
+ * 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., 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 DoWork ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
+ aout_buffer_t * );
+
+/*****************************************************************************
+ * Module descriptor
+ *****************************************************************************/
+vlc_module_begin();
+ set_description( _("audio filter for simple channel mixing") );
+ set_capability( "audio filter", 10 );
+ set_callbacks( Create, NULL );
+vlc_module_end();
+
+/*****************************************************************************
+ * Create: allocate trivial channel mixer
+ *****************************************************************************/
+static int Create( vlc_object_t *p_this )
+{
+ aout_filter_t * p_filter = (aout_filter_t *)p_this;
+
+ if ( (p_filter->input.i_physical_channels
+ == p_filter->output.i_physical_channels
+ && p_filter->input.i_original_channels
+ == p_filter->output.i_original_channels)
+ || p_filter->input.i_format != p_filter->output.i_format
+ || p_filter->input.i_rate != p_filter->output.i_rate
+ || p_filter->input.i_format != VLC_FOURCC('f','l','3','2') )
+ {
+ return -1;
+ }
+
+ msg_Err( p_this, aout_FormatPrintChannels( &p_filter->input ) );
+
+ /* Only conversion to Stereo right now */
+ if( p_filter->output.i_physical_channels !=
+ (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT) ) return -1;
+
+ /* Only from 7/7.1/5/5.1 */
+ if( (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
+ (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
+ AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) &&
+ (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
+ (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
+ AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT |
+ AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) )
+ {
+ return -1;
+ }
+
+ p_filter->pf_do_work = DoWork;
+ p_filter->b_in_place = 0;
+
+ return 0;
+}
+
+/*****************************************************************************
+ * 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 )
+{
+ int i_input_nb = aout_FormatNbChannels( &p_filter->input );
+ int i_output_nb = aout_FormatNbChannels( &p_filter->output );
+ float *p_dest = (float *)p_out_buf->p_buffer;
+ float *p_src = (float *)p_in_buf->p_buffer;
+ int i;
+
+ p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
+ p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
+
+ if( p_filter->input.i_physical_channels & AOUT_CHAN_MIDDLELEFT )
+ for( i = p_in_buf->i_nb_samples; i--; )
+ {
+ *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 4 + p_src[4] / 4;
+ p_dest++;
+ *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 4 + p_src[5] / 4;
+ p_dest++;
+
+ p_src += 7;
+
+ if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
+ }
+ else
+ for( i = p_in_buf->i_nb_samples; i--; )
+ {
+ *p_dest = p_src[4] + 0.5 * p_src[0] + 0.33 * p_src[2];
+ p_dest++;
+ *p_dest = p_src[4] + 0.5 * p_src[1] + 0.33 * p_src[3];
+ p_dest++;
+
+ p_src += 5;
+
+ if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
+ }
+}