git.sesse.net Git - vlc/blob - src/audio_output/mixer.c

   1 /*****************************************************************************
   2  * mixer.c : audio output mixing operations
   3  *****************************************************************************
   4  * Copyright (C) 2002 VideoLAN
   5  * $Id: mixer.c,v 1.8 2002/08/19 23:12:57 massiot Exp $
   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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #include <stdlib.h>                            /* calloc(), malloc(), free() */
  28 #include <string.h>
  29
  30 #include <vlc/vlc.h>
  31
  32 #ifdef HAVE_ALLOCA_H
  33 #   include <alloca.h>
  34 #endif
  35
  36 #include "audio_output.h"
  37 #include "aout_internal.h"
  38
  39 /*****************************************************************************
  40  * aout_MixerNew: prepare a mixer plug-in
  41  *****************************************************************************/
  42 int aout_MixerNew( aout_instance_t * p_aout )
  43 {
  44     p_aout->mixer.p_module = module_Need( p_aout, "audio mixer", NULL );
  45     if ( p_aout->mixer.p_module == NULL )
  46     {
  47         msg_Err( p_aout, "no suitable aout mixer" );
  48         return -1;
  49     }
  50     return 0;
  51 }
  52
  53 /*****************************************************************************
  54  * aout_MixerDelete: delete the mixer
  55  *****************************************************************************/
  56 void aout_MixerDelete( aout_instance_t * p_aout )
  57 {
  58     module_Unneed( p_aout, p_aout->mixer.p_module );
  59 }
  60
  61 /*****************************************************************************
  62  * MixBuffer: try to prepare one output buffer
  63  *****************************************************************************/
  64 static int MixBuffer( aout_instance_t * p_aout )
  65 {
  66     int             i;
  67     aout_buffer_t * p_output_buffer;
  68     mtime_t start_date, end_date;
  69
  70     /* Retrieve the date of the next buffer. */
  71     vlc_mutex_lock( &p_aout->mixer_lock );
  72     start_date = aout_FifoNextStart( p_aout, &p_aout->output.fifo );
  73     if ( start_date != 0 && start_date < mdate() )
  74     {
  75         /* The output is _very_ late. This can only happen if the user
  76          * pauses the stream (or if the decoder is buggy, which cannot
  77          * happen :). */
  78         msg_Warn( p_aout, "Output PTS is out of range (%lld), clearing out",
  79                   start_date );
  80         start_date = p_aout->output.fifo.end_date = 0;
  81     }
  82
  83     /* See if we have enough data to prepare a new buffer for the audio
  84      * output. First : start date. */
  85     if ( !start_date )
  86     {
  87         /* Find the latest start date available. */
  88         for ( i = 0; i < p_aout->i_nb_inputs; i++ )
  89         {
  90             aout_input_t * p_input = p_aout->pp_inputs[i];
  91             aout_fifo_t * p_fifo = &p_input->fifo;
  92             aout_buffer_t * p_buffer;
  93
  94             p_buffer = p_fifo->p_first;
  95             if ( p_buffer == NULL )
  96             {
  97                 break;
  98             }
  99
 100             if ( !start_date || start_date < p_buffer->start_date )
 101             {
 102                 start_date = p_buffer->start_date;
 103             }
 104         }
 105
 106         if ( i < p_aout->i_nb_inputs )
 107         {
 108             /* Interrupted before the end... We can't run. */
 109             vlc_mutex_unlock( &p_aout->mixer_lock );
 110             return -1;
 111         }
 112     }
 113     end_date = start_date + (mtime_t)p_aout->output.i_nb_samples * 1000000
 114                              / p_aout->output.output.i_rate;
 115
 116     /* Check that start_date and end_date are available for all input
 117      * streams. */
 118     for ( i = 0; i < p_aout->i_nb_inputs; i++ )
 119     {
 120         aout_input_t * p_input = p_aout->pp_inputs[i];
 121         aout_fifo_t * p_fifo = &p_input->fifo;
 122         aout_buffer_t * p_buffer;
 123         mtime_t prev_date;
 124         vlc_bool_t b_drop_buffers;
 125
 126         p_buffer = p_fifo->p_first;
 127         if ( p_buffer == NULL )
 128         {
 129             break;
 130         }
 131
 132         /* Check for the continuity of start_date */
 133         while ( p_buffer != NULL && p_buffer->end_date < start_date )
 134         {
 135             aout_buffer_t * p_next = p_buffer->p_next;
 136             msg_Err( p_aout, "the mixer got a packet in the past (%lld)",
 137                      start_date - p_buffer->end_date );
 138             aout_BufferFree( p_buffer );
 139             p_fifo->p_first = p_buffer = p_next;
 140             p_input->p_first_byte_to_mix = NULL;
 141         }
 142         if ( p_buffer == NULL )
 143         {
 144             p_fifo->pp_last = &p_fifo->p_first;
 145             break;
 146         }
 147
 148         if ( !AOUT_FMT_NON_LINEAR( &p_aout->mixer.mixer ) )
 149         {
 150             /* Additionally check that p_first_byte_to_mix is well
 151              * located. */
 152             unsigned long i_nb_bytes = (start_date - p_buffer->start_date)
 153                             * p_aout->mixer.mixer.i_bytes_per_frame
 154                             * p_aout->mixer.mixer.i_rate
 155                             / p_aout->mixer.mixer.i_frame_length
 156                             / 1000000;
 157             ptrdiff_t mixer_nb_bytes;
 158
 159             if ( p_input->p_first_byte_to_mix == NULL )
 160             {
 161                 p_input->p_first_byte_to_mix = p_buffer->p_buffer;
 162             }
 163             mixer_nb_bytes = p_input->p_first_byte_to_mix
 164                               - p_buffer->p_buffer;
 165
 166             if ( i_nb_bytes + p_aout->mixer.mixer.i_bytes_per_frame
 167                   < mixer_nb_bytes ||
 168                  i_nb_bytes - p_aout->mixer.mixer.i_bytes_per_frame
 169                   > mixer_nb_bytes )
 170             {
 171                 msg_Warn( p_aout,
 172                           "mixer start isn't output start (%ld)",
 173                           i_nb_bytes - mixer_nb_bytes );
 174
 175                 /* Round to the nearest multiple */
 176                 i_nb_bytes /= p_aout->mixer.mixer.i_bytes_per_frame;
 177                 i_nb_bytes *= p_aout->mixer.mixer.i_bytes_per_frame;
 178                 p_input->p_first_byte_to_mix = p_buffer->p_buffer
 179                                                 + i_nb_bytes;
 180             }
 181         }
 182
 183         /* Check that we have enough samples. */
 184         for ( ; ; )
 185         {
 186             p_buffer = p_fifo->p_first;
 187             if ( p_buffer == NULL ) break;
 188             if ( p_buffer->end_date >= end_date ) break;
 189
 190             /* Check that all buffers are contiguous. */
 191             prev_date = p_fifo->p_first->end_date;
 192             p_buffer = p_buffer->p_next;
 193             b_drop_buffers = 0;
 194             for ( ; p_buffer != NULL; p_buffer = p_buffer->p_next )
 195             {
 196                 if ( prev_date != p_buffer->start_date )
 197                 {
 198                     msg_Warn( p_aout,
 199                               "buffer hole, dropping packets (%lld)",
 200                               p_buffer->start_date - prev_date );
 201                     b_drop_buffers = 1;
 202                     break;
 203                 }
 204                 if ( p_buffer->end_date >= end_date ) break;
 205                 prev_date = p_buffer->end_date;
 206             }
 207             if ( b_drop_buffers )
 208             {
 209                 aout_buffer_t * p_deleted = p_fifo->p_first;
 210                 while ( p_deleted != NULL && p_deleted != p_buffer )
 211                 {
 212                     aout_buffer_t * p_next = p_deleted->p_next;
 213                     aout_BufferFree( p_deleted );
 214                     p_deleted = p_next;
 215                 }
 216                 p_fifo->p_first = p_deleted; /* == p_buffer */
 217             }
 218             else break;
 219         }
 220         if ( p_buffer == NULL ) break;
 221     }
 222
 223     if ( i < p_aout->i_nb_inputs )
 224     {
 225         /* Interrupted before the end... We can't run. */
 226         vlc_mutex_unlock( &p_aout->mixer_lock );
 227         return -1;
 228     }
 229
 230     /* Run the mixer. */
 231     aout_BufferAlloc( &p_aout->mixer.output_alloc,
 232                       ((u64)p_aout->output.i_nb_samples * 1000000)
 233                         / p_aout->output.output.i_rate,
 234                       /* This is a bit kludgy, but is actually only used
 235                        * for the S/PDIF dummy mixer : */
 236                       p_aout->pp_inputs[0]->fifo.p_first,
 237                       p_output_buffer );
 238     if ( p_output_buffer == NULL )
 239     {
 240         msg_Err( p_aout, "out of memory" );
 241         vlc_mutex_unlock( &p_aout->mixer_lock );
 242         return -1;
 243     }
 244     p_output_buffer->i_nb_samples = p_aout->output.i_nb_samples;
 245     p_output_buffer->i_nb_bytes = p_aout->output.i_nb_samples
 246                               * p_aout->mixer.mixer.i_bytes_per_frame
 247                               / p_aout->mixer.mixer.i_frame_length;
 248     p_output_buffer->start_date = start_date;
 249     p_output_buffer->end_date = end_date;
 250
 251     p_aout->mixer.pf_do_work( p_aout, p_output_buffer );
 252
 253     vlc_mutex_unlock( &p_aout->mixer_lock );
 254
 255     aout_OutputPlay( p_aout, p_output_buffer );
 256
 257     return 0;
 258 }
 259
 260 /*****************************************************************************
 261  * aout_MixerRun: entry point for the mixer & post-filters processing
 262  *****************************************************************************/
 263 void aout_MixerRun( aout_instance_t * p_aout )
 264 {
 265     while( MixBuffer( p_aout ) != -1 );
 266 }