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 1.10 2002/08/26 23:00:23 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     audio_date_t exact_start_date;
  70
  71     vlc_mutex_lock( &p_aout->mixer_lock );
  72
  73     /* Retrieve the date of the next buffer. */
  74     memcpy( &exact_start_date, &p_aout->output.fifo.end_date,
  75             sizeof(audio_date_t) );
  76     start_date = aout_DateGet( &exact_start_date );
  77
  78     if ( start_date != 0 && start_date < mdate() )
  79     {
  80         /* The output is _very_ late. This can only happen if the user
  81          * pauses the stream (or if the decoder is buggy, which cannot
  82          * happen :). */
  83         msg_Warn( p_aout, "Output PTS is out of range (%lld), clearing out",
  84                   start_date );
  85         aout_FifoSet( p_aout, &p_aout->output.fifo, 0 );
  86         aout_DateSet( &exact_start_date, 0 );
  87         start_date = 0;
  88     }
  89
  90     /* See if we have enough data to prepare a new buffer for the audio
  91      * output. First : start date. */
  92     if ( !start_date )
  93     {
  94         /* Find the latest start date available. */
  95         for ( i = 0; i < p_aout->i_nb_inputs; i++ )
  96         {
  97             aout_input_t * p_input = p_aout->pp_inputs[i];
  98             aout_fifo_t * p_fifo = &p_input->fifo;
  99             aout_buffer_t * p_buffer;
 100
 101             p_buffer = p_fifo->p_first;
 102             if ( p_buffer == NULL )
 103             {
 104                 break;
 105             }
 106
 107             if ( !start_date || start_date < p_buffer->start_date )
 108             {
 109                 aout_DateSet( &exact_start_date, p_buffer->start_date );
 110                 start_date = p_buffer->start_date;
 111             }
 112         }
 113
 114         if ( i < p_aout->i_nb_inputs )
 115         {
 116             /* Interrupted before the end... We can't run. */
 117             vlc_mutex_unlock( &p_aout->mixer_lock );
 118             return -1;
 119         }
 120     }
 121     aout_DateIncrement( &exact_start_date, p_aout->output.i_nb_samples );
 122     end_date = aout_DateGet( &exact_start_date );
 123
 124     /* Check that start_date and end_date are available for all input
 125      * streams. */
 126     for ( i = 0; i < p_aout->i_nb_inputs; i++ )
 127     {
 128         aout_input_t * p_input = p_aout->pp_inputs[i];
 129         aout_fifo_t * p_fifo = &p_input->fifo;
 130         aout_buffer_t * p_buffer;
 131         mtime_t prev_date;
 132         vlc_bool_t b_drop_buffers;
 133
 134         p_buffer = p_fifo->p_first;
 135         if ( p_buffer == NULL )
 136         {
 137             break;
 138         }
 139
 140         /* Check for the continuity of start_date */
 141         while ( p_buffer != NULL && p_buffer->end_date < start_date )
 142         {
 143             aout_buffer_t * p_next = p_buffer->p_next;
 144             msg_Err( p_aout, "the mixer got a packet in the past (%lld)",
 145                      start_date - p_buffer->end_date );
 146             aout_BufferFree( p_buffer );
 147             p_fifo->p_first = p_buffer = p_next;
 148             p_input->p_first_byte_to_mix = NULL;
 149         }
 150         if ( p_buffer == NULL )
 151         {
 152             p_fifo->pp_last = &p_fifo->p_first;
 153             break;
 154         }
 155
 156         if ( !AOUT_FMT_NON_LINEAR( &p_aout->mixer.mixer ) )
 157         {
 158             /* Additionally check that p_first_byte_to_mix is well
 159              * located. */
 160             unsigned long i_nb_bytes = (start_date - p_buffer->start_date)
 161                             * p_aout->mixer.mixer.i_bytes_per_frame
 162                             * p_aout->mixer.mixer.i_rate
 163                             / p_aout->mixer.mixer.i_frame_length
 164                             / 1000000;
 165             ptrdiff_t mixer_nb_bytes;
 166
 167             if ( p_input->p_first_byte_to_mix == NULL )
 168             {
 169                 p_input->p_first_byte_to_mix = p_buffer->p_buffer;
 170             }
 171             mixer_nb_bytes = p_input->p_first_byte_to_mix
 172                               - p_buffer->p_buffer;
 173
 174             if ( !((i_nb_bytes + p_aout->mixer.mixer.i_bytes_per_frame
 175                      > mixer_nb_bytes) &&
 176                    (i_nb_bytes < p_aout->mixer.mixer.i_bytes_per_frame
 177                      + mixer_nb_bytes)) )
 178             {
 179                 msg_Warn( p_aout,
 180                           "mixer start isn't output start (%d)",
 181                           i_nb_bytes - mixer_nb_bytes );
 182
 183                 /* Round to the nearest multiple */
 184                 i_nb_bytes /= p_aout->mixer.mixer.i_bytes_per_frame;
 185                 i_nb_bytes *= p_aout->mixer.mixer.i_bytes_per_frame;
 186                 p_input->p_first_byte_to_mix = p_buffer->p_buffer
 187                                                 + i_nb_bytes;
 188             }
 189         }
 190
 191         /* Check that we have enough samples. */
 192         for ( ; ; )
 193         {
 194             p_buffer = p_fifo->p_first;
 195             if ( p_buffer == NULL ) break;
 196             if ( p_buffer->end_date >= end_date ) break;
 197
 198             /* Check that all buffers are contiguous. */
 199             prev_date = p_fifo->p_first->end_date;
 200             p_buffer = p_buffer->p_next;
 201             b_drop_buffers = 0;
 202             for ( ; p_buffer != NULL; p_buffer = p_buffer->p_next )
 203             {
 204                 if ( prev_date != p_buffer->start_date )
 205                 {
 206                     msg_Warn( p_aout,
 207                               "buffer hole, dropping packets (%lld)",
 208                               p_buffer->start_date - prev_date );
 209                     b_drop_buffers = 1;
 210                     break;
 211                 }
 212                 if ( p_buffer->end_date >= end_date ) break;
 213                 prev_date = p_buffer->end_date;
 214             }
 215             if ( b_drop_buffers )
 216             {
 217                 aout_buffer_t * p_deleted = p_fifo->p_first;
 218                 while ( p_deleted != NULL && p_deleted != p_buffer )
 219                 {
 220                     aout_buffer_t * p_next = p_deleted->p_next;
 221                     aout_BufferFree( p_deleted );
 222                     p_deleted = p_next;
 223                 }
 224                 p_fifo->p_first = p_deleted; /* == p_buffer */
 225             }
 226             else break;
 227         }
 228         if ( p_buffer == NULL ) break;
 229     }
 230
 231     if ( i < p_aout->i_nb_inputs )
 232     {
 233         /* Interrupted before the end... We can't run. */
 234         vlc_mutex_unlock( &p_aout->mixer_lock );
 235         return -1;
 236     }
 237
 238     /* Run the mixer. */
 239     aout_BufferAlloc( &p_aout->mixer.output_alloc,
 240                       ((u64)p_aout->output.i_nb_samples * 1000000)
 241                         / p_aout->output.output.i_rate,
 242                       /* This is a bit kludgy, but is actually only used
 243                        * for the S/PDIF dummy mixer : */
 244                       p_aout->pp_inputs[0]->fifo.p_first,
 245                       p_output_buffer );
 246     if ( p_output_buffer == NULL )
 247     {
 248         msg_Err( p_aout, "out of memory" );
 249         vlc_mutex_unlock( &p_aout->mixer_lock );
 250         return -1;
 251     }
 252     /* This is again a bit kludgy - for the S/PDIF mixer. */
 253     if ( p_aout->mixer.output_alloc.i_alloc_type != AOUT_ALLOC_NONE )
 254     {
 255         p_output_buffer->i_nb_samples = p_aout->output.i_nb_samples;
 256         p_output_buffer->i_nb_bytes = p_aout->output.i_nb_samples
 257                               * p_aout->mixer.mixer.i_bytes_per_frame
 258                               / p_aout->mixer.mixer.i_frame_length;
 259     }
 260     p_output_buffer->start_date = start_date;
 261     p_output_buffer->end_date = end_date;
 262
 263     p_aout->mixer.pf_do_work( p_aout, p_output_buffer );
 264
 265     vlc_mutex_unlock( &p_aout->mixer_lock );
 266
 267     aout_OutputPlay( p_aout, p_output_buffer );
 268
 269     return 0;
 270 }
 271
 272 /*****************************************************************************
 273  * aout_MixerRun: entry point for the mixer & post-filters processing
 274  *****************************************************************************/
 275 void aout_MixerRun( aout_instance_t * p_aout )
 276 {
 277     while( MixBuffer( p_aout ) != -1 );
 278 }