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 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <vlc_common.h>
  33 #include <vlc_plugin.h>
  34 #include <vlc_aout.h>
  35
  36 /*****************************************************************************
  37  * Local prototypes
  38  *****************************************************************************/
  39 static int  Create    ( vlc_object_t * );
  40
  41 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  42                         aout_buffer_t * );
  43
  44 /*****************************************************************************
  45  * Module descriptor
  46  *****************************************************************************/
  47 vlc_module_begin ()
  48     set_description( N_("Audio filter for ugly resampling") )
  49     set_capability( "audio filter", 2 )
  50     set_category( CAT_AUDIO )
  51     set_subcategory( SUBCAT_AUDIO_MISC )
  52     set_callbacks( Create, NULL )
  53 vlc_module_end ()
  54
  55 /*****************************************************************************
  56  * Create: allocate ugly resampler
  57  *****************************************************************************/
  58 static int Create( vlc_object_t *p_this )
  59 {
  60     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  61
  62     if ( p_filter->input.i_rate == p_filter->output.i_rate
  63           || p_filter->input.i_format != p_filter->output.i_format
  64           || p_filter->input.i_physical_channels
  65               != p_filter->output.i_physical_channels
  66           || p_filter->input.i_original_channels
  67               != p_filter->output.i_original_channels
  68           || (p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
  69                && p_filter->input.i_format != VLC_FOURCC('f','i','3','2')) )
  70     {
  71         return VLC_EGENERIC;
  72     }
  73
  74     p_filter->pf_do_work = DoWork;
  75
  76     /* We don't want a new buffer to be created because we're not sure we'll
  77      * actually need to resample anything. */
  78     p_filter->b_in_place = true;
  79
  80     return VLC_SUCCESS;
  81 }
  82
  83 /*****************************************************************************
  84  * DoWork: convert a buffer
  85  *****************************************************************************/
  86 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
  87                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
  88 {
  89     int32_t *p_in, *p_out = (int32_t*)p_out_buf->p_buffer;
  90 #ifndef HAVE_ALLOCA
  91     int32_t *p_in_orig;
  92 #endif
  93
  94     unsigned int i_nb_channels = aout_FormatNbChannels( &p_filter->input );
  95     unsigned int i_in_nb = p_in_buf->i_nb_samples;
  96     unsigned int i_out_nb = i_in_nb * p_filter->output.i_rate
  97                                     / p_filter->input.i_rate;
  98     unsigned int i_sample_bytes = i_nb_channels * sizeof(int32_t);
  99     unsigned int i_out, i_chan, i_remainder = 0;
 100
 101     /* Check if we really need to run the resampler */
 102     if( p_aout->mixer.mixer.i_rate == p_filter->input.i_rate )
 103     {
 104         return;
 105     }
 106
 107 #ifdef HAVE_ALLOCA
 108     p_in = (int32_t *)alloca( p_in_buf->i_nb_bytes );
 109 #else
 110     p_in_orig = p_in = (int32_t *)malloc( p_in_buf->i_nb_bytes );
 111 #endif
 112     if( p_in == NULL )
 113     {
 114         return;
 115     }
 116
 117     vlc_memcpy( p_in, p_in_buf->p_buffer, p_in_buf->i_nb_bytes );
 118
 119     for( i_out = i_out_nb ; i_out-- ; )
 120     {
 121         for( i_chan = i_nb_channels ; i_chan ; )
 122         {
 123             i_chan--;
 124             p_out[i_chan] = p_in[i_chan];
 125         }
 126         p_out += i_nb_channels;
 127
 128         i_remainder += p_filter->input.i_rate;
 129         while( i_remainder >= p_filter->output.i_rate )
 130         {
 131             p_in += i_nb_channels;
 132             i_remainder -= p_filter->output.i_rate;
 133         }
 134     }
 135
 136     p_out_buf->i_nb_samples = i_out_nb;
 137     p_out_buf->i_nb_bytes = i_out_nb * i_sample_bytes;
 138     p_out_buf->start_date = p_in_buf->start_date;
 139     p_out_buf->end_date = p_out_buf->start_date + p_out_buf->i_nb_samples *
 140         1000000 / p_filter->output.i_rate;
 141
 142 #ifndef HAVE_ALLOCA
 143     free( p_in_orig );
 144 #endif
 145
 146 }