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 #include <vlc_filter.h>
  36
  37 /*****************************************************************************
  38  * Local prototypes
  39  *****************************************************************************/
  40 static int  Create    ( vlc_object_t * );
  41
  42 static block_t *DoWork( filter_t *, block_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     filter_t * p_filter = (filter_t *)p_this;
  61
  62     if ( p_filter->fmt_in.audio.i_rate == p_filter->fmt_out.audio.i_rate
  63           || p_filter->fmt_in.audio.i_format != p_filter->fmt_out.audio.i_format
  64           || p_filter->fmt_in.audio.i_physical_channels
  65               != p_filter->fmt_out.audio.i_physical_channels
  66           || p_filter->fmt_in.audio.i_original_channels
  67               != p_filter->fmt_out.audio.i_original_channels
  68           || (p_filter->fmt_in.audio.i_format != VLC_CODEC_FL32
  69                && p_filter->fmt_in.audio.i_format != VLC_CODEC_FI32) )
  70     {
  71         return VLC_EGENERIC;
  72     }
  73
  74     p_filter->pf_audio_filter = DoWork;
  75     return VLC_SUCCESS;
  76 }
  77
  78 /*****************************************************************************
  79  * DoWork: convert a buffer
  80  *****************************************************************************/
  81 static block_t *DoWork( filter_t * p_filter, block_t * p_in_buf )
  82 {
  83     /* Check if we really need to run the resampler */
  84     if( p_filter->fmt_out.audio.i_rate == p_filter->fmt_in.audio.i_rate )
  85         return p_in_buf;
  86
  87     block_t *p_out_buf = p_in_buf;
  88     unsigned int i_out_nb = p_in_buf->i_nb_samples
  89         * p_filter->fmt_out.audio.i_rate / p_filter->fmt_in.audio.i_rate;
  90     const unsigned int i_sample_bytes =
  91         aout_FormatNbChannels( &p_filter->fmt_in.audio ) * sizeof(int32_t);
  92
  93     if( p_filter->fmt_out.audio.i_rate > p_filter->fmt_in.audio.i_rate )
  94     {
  95         p_out_buf = block_Alloc( i_out_nb * i_sample_bytes );
  96         if( !p_out_buf )
  97             goto out;
  98     }
  99
 100     unsigned char *p_out = p_out_buf->p_buffer;
 101     unsigned char *p_in = p_in_buf->p_buffer;
 102     unsigned int i_remainder = 0;
 103
 104     p_out_buf->i_nb_samples = i_out_nb;
 105     p_out_buf->i_buffer = i_out_nb * i_sample_bytes;
 106     p_out_buf->i_pts = p_in_buf->i_pts;
 107     p_out_buf->i_length = p_out_buf->i_nb_samples *
 108         1000000 / p_filter->fmt_out.audio.i_rate;
 109
 110     while( i_out_nb )
 111     {
 112         if( p_out != p_in )
 113             memcpy( p_out, p_in, i_sample_bytes );
 114         p_out += i_sample_bytes;
 115         i_out_nb--;
 116
 117         i_remainder += p_filter->fmt_in.audio.i_rate;
 118         while( i_remainder >= p_filter->fmt_out.audio.i_rate )
 119         {
 120             p_in += i_sample_bytes;
 121             i_remainder -= p_filter->fmt_out.audio.i_rate;
 122         }
 123     }
 124
 125     if( p_in_buf != p_out_buf )
 126 out:
 127         block_Release( p_in_buf );
 128     return p_out_buf;
 129 }