git.sesse.net Git - vlc/blob - modules/audio_mixer/trivial.c

   1 /*****************************************************************************
   2  * trivial.c : trivial mixer plug-in (1 input, no downmixing)
   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 #include <stdlib.h>                                      /* malloc(), free() */
  28 #include <string.h>
  29
  30 #include <vlc/vlc.h>
  31 #include <vlc_aout.h>
  32
  33 /*****************************************************************************
  34  * Local prototypes
  35  *****************************************************************************/
  36 static int  Create    ( vlc_object_t * );
  37
  38 static void DoWork    ( aout_instance_t *, aout_buffer_t * );
  39
  40 /*****************************************************************************
  41  * Module descriptor
  42  *****************************************************************************/
  43 vlc_module_begin();
  44     set_category( CAT_AUDIO );
  45     set_subcategory( SUBCAT_AUDIO_MISC );
  46     set_description( _("Trivial audio mixer") );
  47     set_capability( "audio mixer", 1 );
  48     set_callbacks( Create, NULL );
  49 vlc_module_end();
  50
  51 /*****************************************************************************
  52  * Create: allocate trivial mixer
  53  *****************************************************************************/
  54 static int Create( vlc_object_t *p_this )
  55 {
  56     aout_instance_t * p_aout = (aout_instance_t *)p_this;
  57
  58     if ( p_aout->mixer.mixer.i_format != VLC_FOURCC('f','l','3','2')
  59           && p_aout->mixer.mixer.i_format != VLC_FOURCC('f','i','3','2') )
  60     {
  61         return -1;
  62     }
  63
  64     p_aout->mixer.pf_do_work = DoWork;
  65
  66     return 0;
  67 }
  68
  69 /*****************************************************************************
  70  * DoWork: mix a new output buffer
  71  *****************************************************************************/
  72 static void DoWork( aout_instance_t * p_aout, aout_buffer_t * p_buffer )
  73 {
  74     int i = 0;
  75     aout_input_t * p_input = p_aout->pp_inputs[i];
  76     int i_nb_channels = aout_FormatNbChannels( &p_aout->mixer.mixer );
  77     int i_nb_bytes = p_buffer->i_nb_samples * sizeof(int32_t)
  78                       * i_nb_channels;
  79     byte_t * p_in;
  80     byte_t * p_out;
  81
  82     while ( p_input->b_error )
  83     {
  84         p_input = p_aout->pp_inputs[++i];
  85         /* This can't crash because if no input has b_error == 0, the
  86          * audio mixer cannot run and we can't be here. */
  87     }
  88     p_in = p_input->p_first_byte_to_mix;
  89     p_out = p_buffer->p_buffer;
  90
  91     for ( ; ; )
  92     {
  93         ptrdiff_t i_available_bytes = (p_input->fifo.p_first->p_buffer
  94                                         - p_in)
  95                                         + p_input->fifo.p_first->i_nb_samples
  96                                            * sizeof(int32_t)
  97                                            * i_nb_channels;
  98
  99         if ( i_available_bytes < i_nb_bytes )
 100         {
 101             aout_buffer_t * p_old_buffer;
 102
 103             if ( i_available_bytes > 0 )
 104                 p_aout->p_libvlc->pf_memcpy( p_out, p_in, i_available_bytes );
 105             i_nb_bytes -= i_available_bytes;
 106             p_out += i_available_bytes;
 107
 108             /* Next buffer */
 109             p_old_buffer = aout_FifoPop( p_aout, &p_input->fifo );
 110             aout_BufferFree( p_old_buffer );
 111             if ( p_input->fifo.p_first == NULL )
 112             {
 113                 msg_Err( p_aout, "internal amix error" );
 114                 return;
 115             }
 116             p_in = p_input->fifo.p_first->p_buffer;
 117         }
 118         else
 119         {
 120             if ( i_nb_bytes > 0 )
 121                 p_aout->p_libvlc->pf_memcpy( p_out, p_in, i_nb_bytes );
 122             p_input->p_first_byte_to_mix = p_in + i_nb_bytes;
 123             break;
 124         }
 125     }
 126
 127     /* Empty other FIFOs to avoid a memory leak. */
 128     for ( i++; i < p_aout->i_nb_inputs; i++ )
 129     {
 130         aout_fifo_t * p_fifo;
 131         aout_buffer_t * p_deleted;
 132
 133         p_input = p_aout->pp_inputs[i];
 134         if ( p_input->b_error ) continue;
 135         p_fifo = &p_input->fifo;
 136         p_deleted = p_fifo->p_first;
 137         while ( p_deleted != NULL )
 138         {
 139             aout_buffer_t * p_next = p_deleted->p_next;
 140             aout_BufferFree( p_deleted );
 141             p_deleted = p_next;
 142         }
 143         p_fifo->p_first = NULL;
 144         p_fifo->pp_last = &p_fifo->p_first;
 145     }
 146 }
 147