git.sesse.net Git - vlc/blob - modules/audio_filter/resampler/ugly.c

   1 /*****************************************************************************
   2  * ugly.c : ugly resampler (changes pitch)
   3  *****************************************************************************
   4  * Copyright (C) 2002 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Samuel Hocevar <sam@zoy.org>
   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 "audio_output.h"
  32 #include "aout_internal.h"
  33
  34 /*****************************************************************************
  35  * Local prototypes
  36  *****************************************************************************/
  37 static int  Create    ( vlc_object_t * );
  38
  39 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  40                         aout_buffer_t * );
  41
  42 /*****************************************************************************
  43  * Module descriptor
  44  *****************************************************************************/
  45 vlc_module_begin();
  46     set_description( _("audio filter for ugly resampling") );
  47     set_capability( "audio filter", 2 );
  48     set_category( CAT_AUDIO );
  49     set_subcategory( SUBCAT_AUDIO_MISC );
  50     set_callbacks( Create, NULL );
  51 vlc_module_end();
  52
  53 /*****************************************************************************
  54  * Create: allocate ugly resampler
  55  *****************************************************************************/
  56 static int Create( vlc_object_t *p_this )
  57 {
  58     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  59
  60     if ( p_filter->input.i_rate == p_filter->output.i_rate
  61           || p_filter->input.i_format != p_filter->output.i_format
  62           || p_filter->input.i_physical_channels
  63               != p_filter->output.i_physical_channels
  64           || p_filter->input.i_original_channels
  65               != p_filter->output.i_original_channels
  66           || (p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
  67                && p_filter->input.i_format != VLC_FOURCC('f','i','3','2')) )
  68     {
  69         return VLC_EGENERIC;
  70     }
  71
  72     p_filter->pf_do_work = DoWork;
  73
  74     /* We don't want a new buffer to be created because we're not sure we'll
  75      * actually need to resample anything. */
  76     p_filter->b_in_place = VLC_TRUE;
  77
  78     return VLC_SUCCESS;
  79 }
  80
  81 /*****************************************************************************
  82  * DoWork: convert a buffer
  83  *****************************************************************************/
  84 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
  85                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
  86 {
  87     int32_t *p_in, *p_out = (int32_t*)p_out_buf->p_buffer;
  88 #ifndef HAVE_ALLOCA
  89     int32_t *p_in_orig;
  90 #endif
  91
  92     unsigned int i_nb_channels = aout_FormatNbChannels( &p_filter->input );
  93     unsigned int i_in_nb = p_in_buf->i_nb_samples;
  94     unsigned int i_out_nb = i_in_nb * p_filter->output.i_rate
  95                                     / p_filter->input.i_rate;
  96     unsigned int i_sample_bytes = i_nb_channels * sizeof(int32_t);
  97     unsigned int i_out, i_chan, i_remainder = 0;
  98
  99     /* Check if we really need to run the resampler */
 100     if( p_aout->mixer.mixer.i_rate == p_filter->input.i_rate )
 101     {
 102         return;
 103     }
 104
 105 #ifdef HAVE_ALLOCA
 106     p_in = (int32_t *)alloca( p_in_buf->i_nb_bytes );
 107 #else
 108     p_in_orig = p_in = (int32_t *)malloc( p_in_buf->i_nb_bytes );
 109 #endif
 110     if( p_in == NULL )
 111     {
 112         return;
 113     }
 114
 115     p_aout->p_vlc->pf_memcpy( p_in, p_in_buf->p_buffer, p_in_buf->i_nb_bytes );
 116
 117     for( i_out = i_out_nb ; i_out-- ; )
 118     {
 119         for( i_chan = i_nb_channels ; i_chan ; )
 120         {
 121             i_chan--;
 122             p_out[i_chan] = p_in[i_chan];
 123         }
 124         p_out += i_nb_channels;
 125
 126         i_remainder += p_filter->input.i_rate;
 127         while( i_remainder >= p_filter->output.i_rate )
 128         {
 129             p_in += i_nb_channels;
 130             i_remainder -= p_filter->output.i_rate;
 131         }
 132     }
 133
 134     p_out_buf->i_nb_samples = i_out_nb;
 135     p_out_buf->i_nb_bytes = i_out_nb * i_sample_bytes;
 136     p_out_buf->start_date = p_in_buf->start_date;
 137     p_out_buf->end_date = p_out_buf->start_date + p_out_buf->i_nb_samples *
 138         1000000 / p_filter->output.i_rate;
 139
 140 #ifndef HAVE_ALLOCA
 141     free( p_in_orig );
 142 #endif
 143
 144 }