git.sesse.net Git - mlt/blob - src/modules/resample/filter_resample.c

   1 /*
   2  * filter_resample.c -- adjust audio sample frequency
   3  * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
   4  * Author: Dan Dennedy <dan@dennedy.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 #include "filter_resample.h"
  22
  23 #include <framework/mlt_frame.h>
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <samplerate.h>
  28 #define __USE_ISOC99 1
  29 #include <math.h>
  30
  31 #define BUFFER_LEN 20480
  32 #define RESAMPLE_TYPE SRC_SINC_FASTEST
  33
  34 /** Get the audio.
  35 */
  36
  37 static int resample_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
  38 {
  39         // Get the properties of the a frame
  40         mlt_properties properties = mlt_frame_properties( frame );
  41         int output_rate = mlt_properties_get_int( properties, "resample.frequency" );
  42         SRC_STATE *state = mlt_properties_get_data( properties, "resample.state", NULL );
  43         SRC_DATA data;
  44         float *input_buffer = mlt_properties_get_data( properties, "resample.input_buffer", NULL );
  45         float *output_buffer = mlt_properties_get_data( properties, "resample.output_buffer", NULL );
  46         int channels_avail = *channels;
  47         int i;
  48
  49         if ( output_rate == 0 )
  50                 output_rate = *frequency;
  51
  52         // Restore the original get_audio
  53         frame->get_audio = mlt_properties_get_data( properties, "resample.get_audio", NULL );
  54
  55         // Get the producer's audio
  56         mlt_frame_get_audio( frame, buffer, format, frequency, &channels_avail, samples );
  57
  58         // Duplicate channels as necessary
  59         if ( channels_avail < *channels )
  60         {
  61                 int size = *channels * *samples * 2;
  62                 int16_t *new_buffer = mlt_pool_alloc( size );
  63
  64                 mlt_properties_set_data( properties, "audio", new_buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
  65
  66                 // Duplicate the existing channels
  67                 for ( i = 0; i < *samples; i++ )
  68                 {
  69                         int j, k = 0;
  70                         for ( j = 0; j < *channels; j++ )
  71                         {
  72                                 new_buffer[ ( i * *channels ) + j ] = (*buffer)[ ( i * channels_avail ) + k ];
  73                                 k = ( k + 1 ) % channels_avail;
  74                         }
  75                 }
  76
  77                 *buffer = new_buffer;
  78         }
  79
  80         // Return now if now work to do
  81         if ( output_rate == *frequency )
  82                 return 0;
  83
  84         //fprintf( stderr, "resample_get_audio: input_rate %d output_rate %d\n", *frequency, output_rate );
  85
  86         // Convert to floating point
  87         for ( i = 0; i < *samples * *channels; ++i )
  88                 input_buffer[ i ] = ( float )( (*buffer)[ i ] ) / 32768;
  89
  90         // Resample
  91         data.data_in = input_buffer;
  92         data.data_out = output_buffer;
  93         data.src_ratio = ( float ) output_rate / ( float ) *frequency;
  94         data.input_frames = *samples;
  95         data.output_frames = BUFFER_LEN / *channels;
  96         data.end_of_input = 0;
  97         i = src_process( state, &data );
  98         if ( i == 0 )
  99         {
 100                 if ( data.output_frames_gen > *samples )
 101                 {
 102                         *buffer = mlt_pool_alloc( data.output_frames_gen * *channels * sizeof( int16_t ) );
 103                         mlt_properties_set_data( properties, "audio", *buffer, *channels * data.output_frames_gen * 2, mlt_pool_release, NULL );
 104                 }
 105                 *samples = data.output_frames_gen;
 106                 *frequency = output_rate;
 107
 108                 // Convert from floating back to signed 16bit
 109                 for ( i = 0; i < *samples * *channels; ++i )
 110                 {
 111                         float sample = output_buffer[ i ];
 112                         if ( sample > 1.0 )
 113                                 sample = 1.0;
 114                         if ( sample < -1.0 )
 115                                 sample = -1.0;
 116                         if ( sample >= 0 )
 117                                 (*buffer)[ i ] = lrint( 32767.0 * sample );
 118                         else
 119                                 (*buffer)[ i ] = lrint( 32768.0 * sample );
 120                 }
 121         }
 122         else
 123                 fprintf( stderr, "resample_get_audio: %s %d,%d,%d\n", src_strerror( i ), *frequency, *samples, output_rate );
 124
 125         return 0;
 126 }
 127
 128 /** Filter processing.
 129 */
 130
 131 static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
 132 {
 133         mlt_properties properties = mlt_filter_properties( this );
 134         mlt_properties frame_props = mlt_frame_properties( frame );
 135
 136         // Propogate the frequency property if supplied
 137         if ( mlt_properties_get( properties, "frequency" ) != NULL )
 138                 mlt_properties_set_int( frame_props, "resample.frequency", mlt_properties_get_int( properties, "frequency" ) );
 139
 140         // Propogate the other properties
 141         mlt_properties_set_int( frame_props, "resample.channels", mlt_properties_get_int( properties, "channels" ) );
 142         mlt_properties_set_data( frame_props, "resample.state", mlt_properties_get_data( properties, "state", NULL ), 0, NULL, NULL );
 143         mlt_properties_set_data( frame_props, "resample.input_buffer", mlt_properties_get_data( properties, "input_buffer", NULL ), 0, NULL, NULL );
 144         mlt_properties_set_data( frame_props, "resample.output_buffer", mlt_properties_get_data( properties, "output_buffer", NULL ), 0, NULL, NULL );
 145
 146         // Backup the original get_audio (it's still needed)
 147         mlt_properties_set_data( frame_props, "resample.get_audio", frame->get_audio, 0, NULL, NULL );
 148
 149         // Override the get_audio method
 150         frame->get_audio = resample_get_audio;
 151
 152         return frame;
 153 }
 154
 155 /** Constructor for the filter.
 156 */
 157
 158 mlt_filter filter_resample_init( char *arg )
 159 {
 160         mlt_filter this = mlt_filter_new( );
 161         if ( this != NULL )
 162         {
 163                 int error;
 164                 SRC_STATE *state = src_new( RESAMPLE_TYPE, 2 /* channels */, &error );
 165                 if ( error == 0 )
 166                 {
 167                         void *input_buffer = mlt_pool_alloc( BUFFER_LEN );
 168                         void *output_buffer = mlt_pool_alloc( BUFFER_LEN );
 169                         this->process = filter_process;
 170                         if ( arg != NULL )
 171                                 mlt_properties_set_int( mlt_filter_properties( this ), "frequency", atoi( arg ) );
 172                         mlt_properties_set_int( mlt_filter_properties( this ), "channels", 2 );
 173                         mlt_properties_set_data( mlt_filter_properties( this ), "state", state, 0, (mlt_destructor)src_delete, NULL );
 174                         mlt_properties_set_data( mlt_filter_properties( this ), "input_buffer", input_buffer, BUFFER_LEN, mlt_pool_release, NULL );
 175                         mlt_properties_set_data( mlt_filter_properties( this ), "output_buffer", output_buffer, BUFFER_LEN, mlt_pool_release, NULL );
 176                 }
 177                 else
 178                 {
 179                         fprintf( stderr, "filter_resample_init: %s\n", src_strerror( error ) );
 180                 }
 181         }
 182         return this;
 183 }