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
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <vlc/vlc.h>
  33 #include <vlc_aout.h>
  34
  35 /*****************************************************************************
  36  * Local prototypes
  37  *****************************************************************************/
  38 static int  Create    ( vlc_object_t * );
  39
  40 static void DoWork    ( aout_instance_t *, aout_buffer_t * );
  41
  42 /*****************************************************************************
  43  * Module descriptor
  44  *****************************************************************************/
  45 vlc_module_begin();
  46     set_category( CAT_AUDIO );
  47     set_subcategory( SUBCAT_AUDIO_MISC );
  48     set_description( _("Trivial audio mixer") );
  49     set_capability( "audio mixer", 1 );
  50     set_callbacks( Create, NULL );
  51 vlc_module_end();
  52
  53 /*****************************************************************************
  54  * Create: allocate trivial mixer
  55  *****************************************************************************/
  56 static int Create( vlc_object_t *p_this )
  57 {
  58     aout_instance_t * p_aout = (aout_instance_t *)p_this;
  59
  60     if ( p_aout->mixer.mixer.i_format != VLC_FOURCC('f','l','3','2')
  61           && p_aout->mixer.mixer.i_format != VLC_FOURCC('f','i','3','2') )
  62     {
  63         return -1;
  64     }
  65
  66     p_aout->mixer.pf_do_work = DoWork;
  67
  68     return 0;
  69 }
  70
  71 /*****************************************************************************
  72  * DoWork: mix a new output buffer
  73  *****************************************************************************/
  74 static void DoWork( aout_instance_t * p_aout, aout_buffer_t * p_buffer )
  75 {
  76     int i = 0;
  77     aout_input_t * p_input = p_aout->pp_inputs[i];
  78     int i_nb_channels = aout_FormatNbChannels( &p_aout->mixer.mixer );
  79     int i_nb_bytes = p_buffer->i_nb_samples * sizeof(int32_t)
  80                       * i_nb_channels;
  81     byte_t * p_in;
  82     byte_t * p_out;
  83
  84     while ( p_input->b_error )
  85     {
  86         p_input = p_aout->pp_inputs[++i];
  87         /* This can't crash because if no input has b_error == 0, the
  88          * audio mixer cannot run and we can't be here. */
  89     }
  90     p_in = p_input->p_first_byte_to_mix;
  91     p_out = p_buffer->p_buffer;
  92
  93     for ( ; ; )
  94     {
  95         ptrdiff_t i_available_bytes = (p_input->fifo.p_first->p_buffer
  96                                         - p_in)
  97                                         + p_input->fifo.p_first->i_nb_samples
  98                                            * sizeof(int32_t)
  99                                            * i_nb_channels;
 100
 101         if ( i_available_bytes < i_nb_bytes )
 102         {
 103             aout_buffer_t * p_old_buffer;
 104
 105             if ( i_available_bytes > 0 )
 106                 p_aout->p_libvlc->pf_memcpy( p_out, p_in, i_available_bytes );
 107             i_nb_bytes -= i_available_bytes;
 108             p_out += i_available_bytes;
 109
 110             /* Next buffer */
 111             p_old_buffer = aout_FifoPop( p_aout, &p_input->fifo );
 112             aout_BufferFree( p_old_buffer );
 113             if ( p_input->fifo.p_first == NULL )
 114             {
 115                 msg_Err( p_aout, "internal amix error" );
 116                 return;
 117             }
 118             p_in = p_input->fifo.p_first->p_buffer;
 119         }
 120         else
 121         {
 122             if ( i_nb_bytes > 0 )
 123                 p_aout->p_libvlc->pf_memcpy( p_out, p_in, i_nb_bytes );
 124             p_input->p_first_byte_to_mix = p_in + i_nb_bytes;
 125             break;
 126         }
 127     }
 128
 129     /* Empty other FIFOs to avoid a memory leak. */
 130     for ( i++; i < p_aout->i_nb_inputs; i++ )
 131     {
 132         aout_fifo_t * p_fifo;
 133         aout_buffer_t * p_deleted;
 134
 135         p_input = p_aout->pp_inputs[i];
 136         if ( p_input->b_error ) continue;
 137         p_fifo = &p_input->fifo;
 138         p_deleted = p_fifo->p_first;
 139         while ( p_deleted != NULL )
 140         {
 141             aout_buffer_t * p_next = p_deleted->p_next;
 142             aout_BufferFree( p_deleted );
 143             p_deleted = p_next;
 144         }
 145         p_fifo->p_first = NULL;
 146         p_fifo->pp_last = &p_fifo->p_first;
 147     }
 148 }
 149