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 <framework/mlt_filter.h>
  22 #include <framework/mlt_frame.h>
  23 #include <framework/mlt_log.h>
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <samplerate.h>
  28 #include <string.h>
  29
  30 // BUFFER_LEN is based on a maximum of 96KHz, 5 fps, 8 channels
  31 // TODO: dynamically allocate larger buffer size
  32 #define BUFFER_LEN ((96000/5) * 8 * sizeof(float))
  33 #define RESAMPLE_TYPE SRC_SINC_FASTEST
  34
  35 /** Get the audio.
  36 */
  37
  38 static int resample_get_audio( mlt_frame frame, void **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
  39 {
  40         // Get the filter service
  41         mlt_filter filter = mlt_frame_pop_audio( frame );
  42
  43         // Get the filter properties
  44         mlt_properties filter_properties = MLT_FILTER_PROPERTIES( filter );
  45
  46         // Get the resample information
  47         int output_rate = mlt_properties_get_int( filter_properties, "frequency" );
  48
  49         // If no resample frequency is specified, default to requested value
  50         if ( output_rate == 0 )
  51                 output_rate = *frequency;
  52
  53         // Get the producer's audio
  54         int error = mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
  55         if ( error ) return error;
  56
  57         // Return now if no work to do
  58         if ( output_rate != *frequency && *frequency > 0 && *channels > 0 )
  59         {
  60                 mlt_log_debug( MLT_FILTER_SERVICE(filter), "channels %d samples %d frequency %d -> %d\n",
  61                         *channels, *samples, *frequency, output_rate );
  62
  63                 // Do not convert to float unless we need to change the rate
  64                 if ( *format != mlt_audio_f32le )
  65                         frame->convert_audio( frame, buffer, format, mlt_audio_f32le );
  66
  67                 mlt_service_lock( MLT_FILTER_SERVICE(filter) );
  68
  69                 SRC_DATA data;
  70                 data.data_in = *buffer;
  71                 data.data_out = mlt_properties_get_data( filter_properties, "output_buffer", NULL );
  72                 data.src_ratio = ( float ) output_rate / ( float ) *frequency;
  73                 data.input_frames = *samples;
  74                 data.output_frames = BUFFER_LEN / *channels;
  75                 data.end_of_input = 0;
  76
  77                 SRC_STATE *state = mlt_properties_get_data( filter_properties, "state", NULL );
  78                 if ( !state || mlt_properties_get_int( filter_properties, "channels" ) != *channels )
  79                 {
  80                         // Recreate the resampler if the number of channels changed
  81                         state = src_new( RESAMPLE_TYPE, *channels, &error );
  82                         mlt_properties_set_data( filter_properties, "state", state, 0, (mlt_destructor) src_delete, NULL );
  83                         mlt_properties_set_int( filter_properties, "channels", *channels );
  84                 }
  85
  86                 // Resample the audio
  87                 error = src_process( state, &data );
  88                 if ( !error )
  89                 {
  90                         // Update output variables
  91                         *samples = data.output_frames_gen;
  92                         *frequency = output_rate;
  93                         *buffer = data.data_out;
  94                 }
  95                 else
  96                 {
  97                         mlt_log_error( MLT_FILTER_SERVICE( filter ), "%s %d,%d,%d\n", src_strerror( error ), *frequency, *samples, output_rate );
  98                 }
  99                 mlt_service_unlock( MLT_FILTER_SERVICE(filter) );
 100         }
 101
 102         return error;
 103 }
 104
 105 /** Filter processing.
 106 */
 107
 108 static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
 109 {
 110         if ( mlt_frame_is_test_audio( frame ) == 0 )
 111         {
 112                 mlt_frame_push_audio( frame, this );
 113                 mlt_frame_push_audio( frame, resample_get_audio );
 114         }
 115
 116         return frame;
 117 }
 118
 119 /** Constructor for the filter.
 120 */
 121
 122 mlt_filter filter_resample_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg )
 123 {
 124         mlt_filter this = mlt_filter_new( );
 125         if ( this != NULL )
 126         {
 127                 int error;
 128                 SRC_STATE *state = src_new( RESAMPLE_TYPE, 2 /* channels */, &error );
 129                 if ( error == 0 )
 130                 {
 131                         void *output_buffer = mlt_pool_alloc( BUFFER_LEN );
 132                         this->process = filter_process;
 133                         if ( arg != NULL )
 134                                 mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "frequency", atoi( arg ) );
 135                         mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "channels", 2 );
 136                         mlt_properties_set_data( MLT_FILTER_PROPERTIES( this ), "state", state, 0, (mlt_destructor)src_delete, NULL );
 137                         mlt_properties_set_data( MLT_FILTER_PROPERTIES( this ), "output_buffer", output_buffer, BUFFER_LEN, mlt_pool_release, NULL );
 138                 }
 139                 else
 140                 {
 141                         fprintf( stderr, "filter_resample_init: %s\n", src_strerror( error ) );
 142                 }
 143         }
 144         return this;
 145 }