modules/audio_mixer/spdif.c

   1 /*****************************************************************************
   2  * spdif.c : dummy mixer for S/PDIF output (1 input only)
   3  *****************************************************************************
   4  * Copyright (C) 2002 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Christophe Massiot <massiot@via.ecp.fr>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <assert.h>
  33
  34 #include <vlc_common.h>
  35 #include <vlc_plugin.h>
  36 #include <vlc_aout.h>
  37
  38 /*****************************************************************************
  39  * Local prototypes
  40  *****************************************************************************/
  41 static int  Create    ( vlc_object_t * );
  42
  43 static void DoWork    ( aout_mixer_t *, aout_buffer_t * );
  44
  45 /*****************************************************************************
  46  * Module descriptor
  47  *****************************************************************************/
  48 vlc_module_begin ()
  49     set_category( CAT_AUDIO )
  50     set_subcategory( SUBCAT_AUDIO_MISC )
  51     set_description( N_("Dummy S/PDIF audio mixer") )
  52     set_capability( "audio mixer", 1 )
  53     set_callbacks( Create, NULL )
  54 vlc_module_end ()
  55
  56 /*****************************************************************************
  57  * Create: allocate spdif mixer
  58  *****************************************************************************/
  59 static int Create( vlc_object_t *p_this )
  60 {
  61     aout_mixer_t *p_mixer = (aout_mixer_t *)p_this;
  62
  63     if ( !AOUT_FMT_NON_LINEAR(&p_mixer->fmt) )
  64     {
  65         return -1;
  66     }
  67
  68     p_mixer->mix = DoWork;
  69     /* This is a bit kludgy - do not ask for a new buffer, since the one
  70      * provided by the first input will be good enough. */
  71     p_mixer->allocation.b_alloc = false;
  72
  73     return 0;
  74 }
  75
  76 /*****************************************************************************
  77  * DoWork: mix a new output buffer - this does nothing, indeed
  78  *****************************************************************************/
  79 static void DoWork( aout_mixer_t * p_mixer, aout_buffer_t * p_buffer )
  80 {
  81     VLC_UNUSED( p_buffer );
  82
  83     unsigned i = 0;
  84     aout_mixer_input_t * p_input = p_mixer->input[i];
  85     while ( p_input->is_invalid )
  86         p_input = p_mixer->input[++i];
  87
  88     aout_buffer_t * p_old_buffer = aout_FifoPop( NULL, &p_input->fifo );
  89     /* We don't free the old buffer because,
  90      * The aout core use a hack to avoid useless memcpy: the buffer in which
  91      * to mix is the same as the one in the first active input fifo.
  92      * So the ownership of that buffer belongs to our caller */
  93     assert( p_old_buffer == p_buffer );
  94
  95     /* Empty other FIFOs to avoid a memory leak. */
  96     for ( i++; i < p_mixer->input_count; i++ )
  97     {
  98         p_input = p_mixer->input[i];
  99         if ( p_input->is_invalid )
 100             continue;
 101         while ((p_old_buffer = aout_FifoPop( NULL, &p_input->fifo )))
 102             aout_BufferFree( p_old_buffer );
 103     }
 104 }
 105