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     unsigned int i_nb_channels = aout_FormatNbChannels( &p_filter->fmt_in.audio );
  88     unsigned int i_in_nb = p_in_buf->i_nb_samples;
  89     unsigned int i_out_nb = i_in_nb * p_filter->fmt_out.audio.i_rate
  90                                     / p_filter->fmt_in.audio.i_rate;
  91     unsigned int i_sample_bytes = i_nb_channels * sizeof(int32_t);
  92
  93     block_t *p_out_buf = block_Alloc( i_out_nb * i_sample_bytes );
  94     if( !p_out_buf )
  95         goto out;
  96
  97     int32_t *p_out = (int32_t*)p_out_buf->p_buffer;
  98     const int32_t *p_in = (int32_t*)p_in_buf->p_buffer;
  99     unsigned int i_remainder = 0;
 100
 101     for( unsigned i_out = i_out_nb ; i_out-- ; )
 102     {
 103         for( unsigned i_chan = i_nb_channels ; i_chan ; )
 104         {
 105             i_chan--;
 106             p_out[i_chan] = p_in[i_chan];
 107         }
 108         p_out += i_nb_channels;
 109
 110         i_remainder += p_filter->fmt_in.audio.i_rate;
 111         while( i_remainder >= p_filter->fmt_out.audio.i_rate )
 112         {
 113             p_in += i_nb_channels;
 114             i_remainder -= p_filter->fmt_out.audio.i_rate;
 115         }
 116     }
 117
 118     p_out_buf->i_nb_samples = i_out_nb;
 119     p_out_buf->i_buffer = i_out_nb * i_sample_bytes;
 120     p_out_buf->i_pts = p_in_buf->i_pts;
 121     p_out_buf->i_length = p_out_buf->i_nb_samples *
 122         1000000 / p_filter->fmt_out.audio.i_rate;
 123 out:
 124     block_Release( p_in_buf );
 125     return p_out_buf;
 126 }