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, 2006 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
  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_filter_t *, aout_buffer_t *,
  37                         aout_buffer_t * );
  38
  39 /*****************************************************************************
  40  * Module descriptor
  41  *****************************************************************************/
  42 vlc_module_begin();
  43     set_description( _("Audio filter for ugly resampling") );
  44     set_capability( "audio filter", 2 );
  45     set_category( CAT_AUDIO );
  46     set_subcategory( SUBCAT_AUDIO_MISC );
  47     set_callbacks( Create, NULL );
  48 vlc_module_end();
  49
  50 /*****************************************************************************
  51  * Create: allocate ugly resampler
  52  *****************************************************************************/
  53 static int Create( vlc_object_t *p_this )
  54 {
  55     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  56
  57     if ( p_filter->input.i_rate == p_filter->output.i_rate
  58           || p_filter->input.i_format != p_filter->output.i_format
  59           || p_filter->input.i_physical_channels
  60               != p_filter->output.i_physical_channels
  61           || p_filter->input.i_original_channels
  62               != p_filter->output.i_original_channels
  63           || (p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
  64                && p_filter->input.i_format != VLC_FOURCC('f','i','3','2')) )
  65     {
  66         return VLC_EGENERIC;
  67     }
  68
  69     p_filter->pf_do_work = DoWork;
  70
  71     /* We don't want a new buffer to be created because we're not sure we'll
  72      * actually need to resample anything. */
  73     p_filter->b_in_place = VLC_TRUE;
  74
  75     return VLC_SUCCESS;
  76 }
  77
  78 /*****************************************************************************
  79  * DoWork: convert a buffer
  80  *****************************************************************************/
  81 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
  82                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
  83 {
  84     int32_t *p_in, *p_out = (int32_t*)p_out_buf->p_buffer;
  85 #ifndef HAVE_ALLOCA
  86     int32_t *p_in_orig;
  87 #endif
  88
  89     unsigned int i_nb_channels = aout_FormatNbChannels( &p_filter->input );
  90     unsigned int i_in_nb = p_in_buf->i_nb_samples;
  91     unsigned int i_out_nb = i_in_nb * p_filter->output.i_rate
  92                                     / p_filter->input.i_rate;
  93     unsigned int i_sample_bytes = i_nb_channels * sizeof(int32_t);
  94     unsigned int i_out, i_chan, i_remainder = 0;
  95
  96     /* Check if we really need to run the resampler */
  97     if( p_aout->mixer.mixer.i_rate == p_filter->input.i_rate )
  98     {
  99         return;
 100     }
 101
 102 #ifdef HAVE_ALLOCA
 103     p_in = (int32_t *)alloca( p_in_buf->i_nb_bytes );
 104 #else
 105     p_in_orig = p_in = (int32_t *)malloc( p_in_buf->i_nb_bytes );
 106 #endif
 107     if( p_in == NULL )
 108     {
 109         return;
 110     }
 111
 112     p_aout->p_libvlc->pf_memcpy( p_in, p_in_buf->p_buffer, p_in_buf->i_nb_bytes );
 113
 114     for( i_out = i_out_nb ; i_out-- ; )
 115     {
 116         for( i_chan = i_nb_channels ; i_chan ; )
 117         {
 118             i_chan--;
 119             p_out[i_chan] = p_in[i_chan];
 120         }
 121         p_out += i_nb_channels;
 122
 123         i_remainder += p_filter->input.i_rate;
 124         while( i_remainder >= p_filter->output.i_rate )
 125         {
 126             p_in += i_nb_channels;
 127             i_remainder -= p_filter->output.i_rate;
 128         }
 129     }
 130
 131     p_out_buf->i_nb_samples = i_out_nb;
 132     p_out_buf->i_nb_bytes = i_out_nb * i_sample_bytes;
 133     p_out_buf->start_date = p_in_buf->start_date;
 134     p_out_buf->end_date = p_out_buf->start_date + p_out_buf->i_nb_samples *
 135         1000000 / p_filter->output.i_rate;
 136
 137 #ifndef HAVE_ALLOCA
 138     free( p_in_orig );
 139 #endif
 140
 141 }