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