]> git.sesse.net Git - vlc/blobdiff - src/audio_output/input.c
* forgot to include the Turkish locale here as well
[vlc] / src / audio_output / input.c
index 62e218e0c43c5891ec88f201ef9a443b224f049e..c39e8cef48195f81a756aba6fc07fe32e263b275 100644 (file)
@@ -1,8 +1,8 @@
 /*****************************************************************************
  * input.c : internal management of input streams for the audio output
  *****************************************************************************
- * Copyright (C) 2002 VideoLAN
- * $Id: input.c,v 1.32 2003/02/21 22:59:38 gbazin Exp $
+ * Copyright (C) 2002-2004 VideoLAN
+ * $Id$
  *
  * Authors: Christophe Massiot <massiot@via.ecp.fr>
  *
@@ -28,6 +28,7 @@
 #include <string.h>
 
 #include <vlc/vlc.h>
+#include <vlc/input.h>                 /* for input_thread_t and i_pts_delay */
 
 #ifdef HAVE_ALLOCA_H
 #   include <alloca.h>
 #include "audio_output.h"
 #include "aout_internal.h"
 
+static int VisualizationCallback( vlc_object_t *, char const *,
+                                  vlc_value_t, vlc_value_t, void * );
+static int EqualizerCallback( vlc_object_t *, char const *,
+                              vlc_value_t, vlc_value_t, void * );
+static aout_filter_t * allocateUserChannelMixer( aout_instance_t *,
+                                                 audio_sample_format_t *,
+                                                 audio_sample_format_t * );
+
 /*****************************************************************************
  * aout_InputNew : allocate a new input and rework the filter pipeline
  *****************************************************************************/
 int aout_InputNew( aout_instance_t * p_aout, aout_input_t * p_input )
 {
-    audio_sample_format_t intermediate_format, headphone_intermediate_format;
-    aout_filter_t * p_headphone_filter;
-    vlc_bool_t b_use_headphone_filter = VLC_FALSE;
+    audio_sample_format_t user_filter_format;
+    audio_sample_format_t intermediate_format;/* input of resampler */
+    vlc_value_t val, text;
+    char * psz_filters, *psz_visual;
+    aout_filter_t * p_user_channel_mixer;
 
     aout_FormatPrint( p_aout, "input", &p_input->input );
 
@@ -56,82 +67,216 @@ int aout_InputNew( aout_instance_t * p_aout, aout_input_t * p_input )
             sizeof(audio_sample_format_t) );
     intermediate_format.i_rate = p_input->input.i_rate;
 
-    /* Headphone filter add-ons. */
-    memcpy( &headphone_intermediate_format, &p_aout->mixer.mixer,
-            sizeof(audio_sample_format_t) );
-    headphone_intermediate_format.i_rate = p_input->input.i_rate;
-    if ( config_GetInt( p_aout , "headphone" ) )
+    /* Try to use the channel mixer chosen by the user */
+    memcpy ( &user_filter_format, &intermediate_format,
+             sizeof(audio_sample_format_t) );
+    user_filter_format.i_physical_channels = p_input->input.i_physical_channels;
+    user_filter_format.i_original_channels = p_input->input.i_original_channels;
+    user_filter_format.i_bytes_per_frame = user_filter_format.i_bytes_per_frame
+                              * aout_FormatNbChannels( &user_filter_format )
+                              / aout_FormatNbChannels( &intermediate_format );
+    p_user_channel_mixer = allocateUserChannelMixer( p_aout, &user_filter_format,
+                                                   &intermediate_format );
+    /* If it failed, let the main pipeline do channel mixing */
+    if ( ! p_user_channel_mixer )
     {
-        /* Do we use heaphone filter ? */
-        if ( intermediate_format.i_physical_channels
-                == ( AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT )
-            && ( intermediate_format.i_format != VLC_FOURCC('f','l','3','2')
-                || intermediate_format.i_format != VLC_FOURCC('f','i','3','2')
-                ) )
-        {
-            b_use_headphone_filter = VLC_TRUE;
-        }
-    }
-    if ( b_use_headphone_filter == VLC_TRUE )
-    {
-        /* Split the filter pipeline. */
-        headphone_intermediate_format.i_physical_channels = p_input->input.i_physical_channels;
-        headphone_intermediate_format.i_original_channels = p_input->input.i_original_channels;
-        headphone_intermediate_format.i_bytes_per_frame =
-                headphone_intermediate_format.i_bytes_per_frame
-                * aout_FormatNbChannels( &headphone_intermediate_format )
-                / aout_FormatNbChannels( &intermediate_format );
+        memcpy ( &user_filter_format, &intermediate_format,
+                 sizeof(audio_sample_format_t) );
     }
 
     /* Create filters. */
     if ( aout_FiltersCreatePipeline( p_aout, p_input->pp_filters,
-                                     &p_input->i_nb_filters, &p_input->input,
-                                     &headphone_intermediate_format ) < 0 )
+                                     &p_input->i_nb_filters,
+                                     &p_input->input,
+                                     &user_filter_format
+                                     ) < 0 )
     {
         msg_Err( p_aout, "couldn't set an input pipeline" );
 
         aout_FifoDestroy( p_aout, &p_input->fifo );
         p_input->b_error = 1;
-
         return -1;
     }
 
-    /* Headphone filter add-ons. */
-    if ( b_use_headphone_filter == VLC_TRUE )
+    /* Now add user filters */
+    if( var_Type( p_aout, "visual" ) == 0 )
     {
-        /* create a vlc object */
-        p_headphone_filter = vlc_object_create( p_aout
-                , sizeof(aout_filter_t) );
-        if ( p_headphone_filter == NULL )
+        module_t *p_module;
+        var_Create( p_aout, "visual", VLC_VAR_STRING | VLC_VAR_HASCHOICE );
+        text.psz_string = _("Visualizations");
+        var_Change( p_aout, "visual", VLC_VAR_SETTEXT, &text, NULL );
+        val.psz_string = ""; text.psz_string = _("Disable");
+        var_Change( p_aout, "visual", VLC_VAR_ADDCHOICE, &val, &text );
+        val.psz_string = "random"; text.psz_string = _("Random");
+        var_Change( p_aout, "visual", VLC_VAR_ADDCHOICE, &val, &text );
+        val.psz_string = "scope"; text.psz_string = _("Scope");
+        var_Change( p_aout, "visual", VLC_VAR_ADDCHOICE, &val, &text );
+        val.psz_string = "spectrum"; text.psz_string = _("Spectrum");
+        var_Change( p_aout, "visual", VLC_VAR_ADDCHOICE, &val, &text );
+
+        /* Look for goom plugin */
+        p_module = config_FindModule( VLC_OBJECT(p_aout), "goom" );
+        if( p_module )
         {
-            msg_Err( p_aout, "couldn't open the headphone virtual spatialization module" );
-            aout_FifoDestroy( p_aout, &p_input->fifo );
-            p_input->b_error = 1;
-            return -1;
+            val.psz_string = "goom"; text.psz_string = "Goom";
+            var_Change( p_aout, "visual", VLC_VAR_ADDCHOICE, &val, &text );
         }
-        vlc_object_attach( p_headphone_filter, p_aout );
-
-        /* find the headphone filter */
-        memcpy( &p_headphone_filter->input, &headphone_intermediate_format
-                , sizeof(audio_sample_format_t) );
-        memcpy( &p_headphone_filter->output, &intermediate_format
-                , sizeof(audio_sample_format_t) );
-        p_headphone_filter->p_module = module_Need( p_headphone_filter, "audio filter"
-                , "headphone" );
-        if ( p_headphone_filter->p_module == NULL )
+
+        /* Look for galaktos plugin */
+        p_module = config_FindModule( VLC_OBJECT(p_aout), "galaktos" );
+        if( p_module )
         {
-            vlc_object_detach( p_headphone_filter );
-            vlc_object_destroy( p_headphone_filter );
+            val.psz_string = "galaktos"; text.psz_string = "GaLaktos";
+            var_Change( p_aout, "visual", VLC_VAR_ADDCHOICE, &val, &text );
+        }
 
-            msg_Err( p_aout, "couldn't open the headphone virtual spatialization module" );
-            aout_FifoDestroy( p_aout, &p_input->fifo );
-            p_input->b_error = 1;
-            return -1;
+        if( var_Get( p_aout, "effect-list", &val ) == VLC_SUCCESS )
+        {
+            var_Set( p_aout, "visual", val );
+            if( val.psz_string ) free( val.psz_string );
+        }
+        var_AddCallback( p_aout, "visual", VisualizationCallback, NULL );
+    }
+
+    if( var_Type( p_aout, "equalizer" ) == 0 )
+    {
+        module_config_t *p_config;
+        int i;
+
+        p_config = config_FindConfig( VLC_OBJECT(p_aout), "equalizer-preset" );
+        if( p_config && p_config->i_list )
+        {
+               var_Create( p_aout, "equalizer",
+                           VLC_VAR_STRING | VLC_VAR_HASCHOICE );
+            text.psz_string = _("Equalizer");
+            var_Change( p_aout, "equalizer", VLC_VAR_SETTEXT, &text, NULL );
+
+            val.psz_string = ""; text.psz_string = _("Disable");
+            var_Change( p_aout, "equalizer", VLC_VAR_ADDCHOICE, &val, &text );
+
+            for( i = 0; i < p_config->i_list; i++ )
+            {
+                val.psz_string = p_config->ppsz_list[i];
+                text.psz_string = p_config->ppsz_list_text[i];
+                var_Change( p_aout, "equalizer", VLC_VAR_ADDCHOICE,
+                            &val, &text );
+            }
+
+            var_AddCallback( p_aout, "equalizer", EqualizerCallback, NULL );
+        }
+    }
+
+    if( var_Type( p_aout, "audio-filter" ) == 0 )
+    {
+        var_Create( p_aout, "audio-filter",
+                    VLC_VAR_STRING | VLC_VAR_DOINHERIT );
+        text.psz_string = _("Audio filters");
+        var_Change( p_aout, "audio-filter", VLC_VAR_SETTEXT, &text, NULL );
+    }
+    if( var_Type( p_aout, "audio-visual" ) == 0 )
+    {
+        var_Create( p_aout, "audio-visual",
+                    VLC_VAR_STRING | VLC_VAR_DOINHERIT );
+        text.psz_string = _("Audio visualizations");
+        var_Change( p_aout, "audio-visual", VLC_VAR_SETTEXT, &text, NULL );
+    }
+
+    var_Get( p_aout, "audio-filter", &val );
+    psz_filters = val.psz_string;
+    var_Get( p_aout, "audio-visual", &val );
+    psz_visual = val.psz_string;
+
+    if( psz_filters && *psz_filters && psz_visual && *psz_visual )
+    {
+        psz_filters = (char *)realloc( psz_filters, strlen( psz_filters ) +
+                                                    strlen( psz_visual )  + 1);
+        sprintf( psz_filters, "%s:%s", psz_filters, psz_visual );
+    }
+    else if(  psz_visual && *psz_visual )
+    {
+        if( psz_filters ) free( psz_filters );
+        psz_filters = strdup( psz_visual );
+    }
+
+    if( psz_filters && *psz_filters )
+    {
+        char *psz_parser = psz_filters;
+        char *psz_next;
+        while( psz_parser && *psz_parser )
+        {
+            aout_filter_t * p_filter;
+
+            if( p_input->i_nb_filters >= AOUT_MAX_FILTERS )
+            {
+                msg_Dbg( p_aout, "max filter reached (%d)", AOUT_MAX_FILTERS );
+                break;
+            }
+
+            while( *psz_parser == ' ' && *psz_parser == ':' )
+            {
+                psz_parser++;
+            }
+            if( ( psz_next = strchr( psz_parser , ':'  ) ) )
+            {
+                *psz_next++ = '\0';
+            }
+            if( *psz_parser =='\0' )
+            {
+                break;
+            }
+
+            msg_Dbg( p_aout, "user filter \"%s\"", psz_parser );
+
+            /* Create a VLC object */
+            p_filter = vlc_object_create( p_aout, sizeof(aout_filter_t) );
+            if( p_filter == NULL )
+            {
+                msg_Err( p_aout, "cannot add user filter %s (skipped)",
+                         psz_parser );
+                psz_parser = psz_next;
+                continue;
+            }
+
+            vlc_object_attach( p_filter , p_aout );
+            memcpy( &p_filter->input, &user_filter_format,
+                    sizeof(audio_sample_format_t) );
+            memcpy( &p_filter->output, &user_filter_format,
+                    sizeof(audio_sample_format_t) );
+
+            p_filter->p_module =
+                module_Need( p_filter,"audio filter", psz_parser, VLC_FALSE );
+
+            if( p_filter->p_module== NULL )
+            {
+                p_filter->p_module =
+                    module_Need( p_filter,"visualization", psz_parser,
+                                                           VLC_FALSE );
+                if( p_filter->p_module == NULL )
+                {
+                    msg_Err( p_aout, "cannot add user filter %s (skipped)",
+                             psz_parser );
+
+                    vlc_object_detach( p_filter );
+                    vlc_object_destroy( p_filter );
+                    psz_parser = psz_next;
+                    continue;
+                }
+            }
+            p_filter->b_continuity = VLC_FALSE;
+
+            p_input->pp_filters[p_input->i_nb_filters++] = p_filter;
+
+            /* next filter if any */
+            psz_parser = psz_next;
         }
+    }
+    if( psz_filters ) free( psz_filters );
+    if( psz_visual ) free( psz_visual );
 
-        /* success */
-        p_headphone_filter->b_reinit = VLC_TRUE;
-        p_input->pp_filters[p_input->i_nb_filters++] = p_headphone_filter;
+    /* Attach the user channel mixer */
+    if ( p_user_channel_mixer )
+    {
+        p_input->pp_filters[p_input->i_nb_filters++] = p_user_channel_mixer;
     }
 
     /* Prepare hints for the buffer allocator. */
@@ -163,6 +308,7 @@ int aout_InputNew( aout_instance_t * p_aout, aout_input_t * p_input )
             aout_FiltersDestroyPipeline( p_aout, p_input->pp_filters,
                                          p_input->i_nb_filters );
             aout_FifoDestroy( p_aout, &p_input->fifo );
+            var_Destroy( p_aout, "visual" );
             p_input->b_error = 1;
 
             return -1;
@@ -191,7 +337,8 @@ int aout_InputNew( aout_instance_t * p_aout, aout_input_t * p_input )
     /* Allocate in the heap, it is more convenient for the decoder. */
     p_input->input_alloc.i_alloc_type = AOUT_ALLOC_HEAP;
 
-    p_input->b_error = 0;
+    p_input->b_error = VLC_FALSE;
+    p_input->b_restart = VLC_FALSE;
 
     return 0;
 }
@@ -224,6 +371,26 @@ int aout_InputPlay( aout_instance_t * p_aout, aout_input_t * p_input,
 {
     mtime_t start_date;
 
+    if( p_input->b_restart )
+    {
+        aout_fifo_t fifo, dummy_fifo;
+        byte_t      *p_first_byte_to_mix;
+
+        vlc_mutex_lock( &p_aout->mixer_lock );
+
+        /* A little trick to avoid loosing our input fifo */
+        aout_FifoInit( p_aout, &dummy_fifo, p_aout->mixer.mixer.i_rate );
+        p_first_byte_to_mix = p_input->p_first_byte_to_mix;
+        fifo = p_input->fifo;
+        p_input->fifo = dummy_fifo;
+        aout_InputDelete( p_aout, p_input );
+        aout_InputNew( p_aout, p_input );
+        p_input->p_first_byte_to_mix = p_first_byte_to_mix;
+        p_input->fifo = fifo;
+
+        vlc_mutex_unlock( &p_aout->mixer_lock );
+    }
+
     /* We don't care if someone changes the start date behind our back after
      * this. We'll deal with that when pushing the buffer, and compensate
      * with the next incoming buffer. */
@@ -248,7 +415,7 @@ int aout_InputPlay( aout_instance_t * p_aout, aout_input_t * p_input,
         if ( p_input->i_nb_resamplers != 0 )
         {
             p_input->pp_resamplers[0]->input.i_rate = p_input->input.i_rate;
-            p_input->pp_resamplers[0]->b_reinit = VLC_TRUE;
+            p_input->pp_resamplers[0]->b_continuity = VLC_FALSE;
         }
         start_date = 0;
     }
@@ -260,13 +427,49 @@ int aout_InputPlay( aout_instance_t * p_aout, aout_input_t * p_input,
         msg_Warn( p_aout, "PTS is out of range ("I64Fd"), dropping buffer",
                   mdate() - p_buffer->start_date );
         aout_BufferFree( p_buffer );
+        p_input->i_resampling_type = AOUT_RESAMPLING_NONE;
+        if ( p_input->i_nb_resamplers != 0 )
+        {
+            p_input->pp_resamplers[0]->input.i_rate = p_input->input.i_rate;
+            p_input->pp_resamplers[0]->b_continuity = VLC_FALSE;
+        }
+        return 0;
+    }
 
+    /* If the audio drift is too big then it's not worth trying to resample
+     * the audio. */
+    if ( start_date != 0 &&
+         ( start_date < p_buffer->start_date - 3 * AOUT_PTS_TOLERANCE ) )
+    {
+        msg_Warn( p_aout, "audio drift is too big ("I64Fd"), clearing out",
+                  start_date - p_buffer->start_date );
+        vlc_mutex_lock( &p_aout->input_fifos_lock );
+        aout_FifoSet( p_aout, &p_input->fifo, 0 );
+        p_input->p_first_byte_to_mix = NULL;
+        vlc_mutex_unlock( &p_aout->input_fifos_lock );
+        if ( p_input->i_resampling_type != AOUT_RESAMPLING_NONE )
+            msg_Warn( p_aout, "timing screwed, stopping resampling" );
+        p_input->i_resampling_type = AOUT_RESAMPLING_NONE;
+        if ( p_input->i_nb_resamplers != 0 )
+        {
+            p_input->pp_resamplers[0]->input.i_rate = p_input->input.i_rate;
+            p_input->pp_resamplers[0]->b_continuity = VLC_FALSE;
+        }
+        start_date = 0;
+    }
+    else if ( start_date != 0 &&
+              ( start_date > p_buffer->start_date + 3 * AOUT_PTS_TOLERANCE ) )
+    {
+        msg_Warn( p_aout, "audio drift is too big ("I64Fd"), dropping buffer",
+                  start_date - p_buffer->start_date );
+        aout_BufferFree( p_buffer );
         return 0;
     }
 
     if ( start_date == 0 ) start_date = p_buffer->start_date;
 
     /* Run pre-filters. */
+
     aout_FiltersPlay( p_aout, p_input->pp_filters, p_input->i_nb_filters,
                       &p_buffer );
 
@@ -308,11 +511,11 @@ int aout_InputPlay( aout_instance_t * p_aout, aout_input_t * p_input,
 
         if( p_input->i_resampling_type == AOUT_RESAMPLING_UP )
         {
-            p_input->pp_resamplers[0]->input.i_rate += 10; /* Hz */
+            p_input->pp_resamplers[0]->input.i_rate += 2; /* Hz */
         }
         else
         {
-            p_input->pp_resamplers[0]->input.i_rate -= 10; /* Hz */
+            p_input->pp_resamplers[0]->input.i_rate -= 2; /* Hz */
         }
 
         /* Check if everything is back to normal, in which case we can stop the
@@ -321,8 +524,10 @@ int aout_InputPlay( aout_instance_t * p_aout, aout_input_t * p_input,
               p_input->input.i_rate )
         {
             p_input->i_resampling_type = AOUT_RESAMPLING_NONE;
-            msg_Warn( p_aout, "resampling stopped after "I64Fi" usec",
-                      mdate() - p_input->i_resamp_start_date );
+            msg_Warn( p_aout, "resampling stopped after "I64Fi" usec "
+                      "(drift: "I64Fi")",
+                      mdate() - p_input->i_resamp_start_date,
+                      p_buffer->start_date - start_date);
         }
         else if( abs( (int)(p_buffer->start_date - start_date) ) <
                  abs( p_input->i_resamp_start_drift ) / 2 )
@@ -353,8 +558,7 @@ int aout_InputPlay( aout_instance_t * p_aout, aout_input_t * p_input,
     p_buffer->start_date = start_date;
 
     /* Actually run the resampler now. */
-    if ( p_input->i_nb_resamplers > 0 && p_aout->mixer.mixer.i_rate !=
-         p_input->pp_resamplers[0]->input.i_rate )
+    if ( p_input->i_nb_resamplers > 0 )
     {
         aout_FiltersPlay( p_aout, p_input->pp_resamplers,
                           p_input->i_nb_resamplers,
@@ -367,3 +571,177 @@ int aout_InputPlay( aout_instance_t * p_aout, aout_input_t * p_input,
 
     return 0;
 }
+
+static int ChangeFiltersString( aout_instance_t * p_aout,
+                                 char *psz_name, vlc_bool_t b_add )
+{
+    vlc_value_t val;
+    char *psz_parser;
+
+    var_Get( p_aout, "audio-filter", &val );
+
+    if( !val.psz_string ) val.psz_string = strdup("");
+
+    psz_parser = strstr( val.psz_string, psz_name );
+
+    if( b_add )
+    {
+        if( !psz_parser )
+        {
+            psz_parser = val.psz_string;
+            asprintf( &val.psz_string, (*val.psz_string) ? "%s:%s" : "%s%s",
+                      val.psz_string, psz_name );
+            free( psz_parser );
+        }
+        else
+        {
+            return 0;
+        }
+    }
+    else
+    {
+        if( psz_parser )
+        {
+            memmove( psz_parser, psz_parser + strlen(psz_name) +
+                     (*(psz_parser + strlen(psz_name)) == ':' ? 1 : 0 ),
+                     strlen(psz_parser + strlen(psz_name)) + 1 );
+        }
+        else
+        {
+            free( val.psz_string );
+            return 0;
+        }
+    }
+
+    var_Set( p_aout, "audio-filter", val );
+    free( val.psz_string );
+    return 1;
+}
+
+static int VisualizationCallback( vlc_object_t *p_this, char const *psz_cmd,
+                       vlc_value_t oldval, vlc_value_t newval, void *p_data )
+{
+    aout_instance_t *p_aout = (aout_instance_t *)p_this;
+    char *psz_mode = newval.psz_string;
+    vlc_value_t val;
+    int i;
+
+    if( !psz_mode || !*psz_mode )
+    {
+        ChangeFiltersString( p_aout, "goom", VLC_FALSE );
+        ChangeFiltersString( p_aout, "visual", VLC_FALSE );
+        ChangeFiltersString( p_aout, "galaktos", VLC_FALSE );
+    }
+    else
+    {
+        if( !strcmp( "goom", psz_mode ) )
+        {
+            ChangeFiltersString( p_aout, "visual", VLC_FALSE );
+            ChangeFiltersString( p_aout, "goom", VLC_TRUE );
+            ChangeFiltersString( p_aout, "galaktos", VLC_FALSE );
+        }
+        else if( !strcmp( "galaktos", psz_mode ) )
+        {
+            ChangeFiltersString( p_aout, "visual", VLC_FALSE );
+            ChangeFiltersString( p_aout, "goom", VLC_FALSE );
+            ChangeFiltersString( p_aout, "galaktos", VLC_TRUE );
+        }
+        else
+        {
+            val.psz_string = psz_mode;
+            var_Create( p_aout, "effect-list", VLC_VAR_STRING );
+            var_Set( p_aout, "effect-list", val );
+
+            ChangeFiltersString( p_aout, "goom", VLC_FALSE );
+            ChangeFiltersString( p_aout, "visual", VLC_TRUE );
+            ChangeFiltersString( p_aout, "galaktos", VLC_FALSE );
+        }
+    }
+
+    /* That sucks */
+    for( i = 0; i < p_aout->i_nb_inputs; i++ )
+    {
+        p_aout->pp_inputs[i]->b_restart = VLC_TRUE;
+    }
+
+    return VLC_SUCCESS;
+}
+
+static int EqualizerCallback( vlc_object_t *p_this, char const *psz_cmd,
+                       vlc_value_t oldval, vlc_value_t newval, void *p_data )
+{
+    aout_instance_t *p_aout = (aout_instance_t *)p_this;
+    char *psz_mode = newval.psz_string;
+    vlc_value_t val;
+    int i;
+    int i_ret;
+
+    if( !psz_mode || !*psz_mode )
+    {
+        i_ret = ChangeFiltersString( p_aout, "equalizer", VLC_FALSE );
+    }
+    else
+    {
+        val.psz_string = psz_mode;
+        var_Create( p_aout, "equalizer-preset", VLC_VAR_STRING );
+        var_Set( p_aout, "equalizer-preset", val );
+        i_ret = ChangeFiltersString( p_aout, "equalizer", VLC_TRUE );
+
+    }
+
+    /* That sucks */
+    if( i_ret == 1 )
+    {
+        for( i = 0; i < p_aout->i_nb_inputs; i++ )
+        {
+            p_aout->pp_inputs[i]->b_restart = VLC_TRUE;
+        }
+    }
+
+    return VLC_SUCCESS;
+}
+
+static aout_filter_t * allocateUserChannelMixer( aout_instance_t * p_aout,
+                                     audio_sample_format_t * p_input_format,
+                                     audio_sample_format_t * p_output_format )
+{
+    aout_filter_t * p_channel_mixer;
+
+    /* Retreive user preferred channel mixer */
+    char * psz_name = config_GetPsz( p_aout, "audio-channel-mixer" );
+
+    /* Not specified => let the main pipeline do the mixing */
+    if ( ! psz_name ) return NULL;
+
+    /* Debug information */
+    aout_FormatsPrint( p_aout, "channel mixer", p_input_format,
+                       p_output_format );
+
+    /* Create a VLC object */
+    p_channel_mixer = vlc_object_create( p_aout, sizeof(aout_filter_t) );
+    if( p_channel_mixer == NULL )
+    {
+        msg_Err( p_aout, "cannot add user channel mixer %s", psz_name );
+        return NULL;
+    }
+    vlc_object_attach( p_channel_mixer , p_aout );
+
+    /* Attach the suitable module */
+    memcpy( &p_channel_mixer->input, p_input_format,
+                    sizeof(audio_sample_format_t) );
+    memcpy( &p_channel_mixer->output, p_output_format,
+                    sizeof(audio_sample_format_t) );
+    p_channel_mixer->p_module =
+        module_Need( p_channel_mixer,"audio filter", psz_name, VLC_TRUE );
+    if( p_channel_mixer->p_module== NULL )
+    {
+        msg_Err( p_aout, "cannot add user channel mixer %s", psz_name );
+        vlc_object_detach( p_channel_mixer );
+        vlc_object_destroy( p_channel_mixer );
+        return NULL;
+    }
+    p_channel_mixer->b_continuity = VLC_FALSE;
+
+    /* Ok */
+    return p_channel_mixer;
+}