2 * filter_resample.c -- adjust audio sample frequency
3 * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
4 * Author: Dan Dennedy <dan@dennedy.org>
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.
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.
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.
21 #include "filter_resample.h"
23 #include <framework/mlt_frame.h>
27 #include <samplerate.h>
28 #define __USE_ISOC99 1
31 #define BUFFER_LEN 20480
32 #define RESAMPLE_TYPE SRC_SINC_FASTEST
37 static int resample_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
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 );
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 );
48 // Restore the original get_audio
49 frame->get_audio = mlt_properties_get_data( properties, "resample.get_audio", NULL );
51 // Get the producer's audio
52 mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
54 // Convert to floating point
55 for ( i = 0; i < *samples * *channels; ++i )
56 input_buffer[ i ] = ( float )( (*buffer)[ i ] ) / 32768;
59 data.data_in = input_buffer;
60 data.data_out = output_buffer;
61 data.src_ratio = ( float ) output_rate / ( float ) *frequency;
62 data.input_frames = *samples;
63 data.output_frames = BUFFER_LEN / *channels;
64 data.end_of_input = 0;
65 i = src_process( state, &data );
68 if ( data.output_frames_gen > *samples )
70 *buffer = (int16_t*) malloc( data.output_frames_gen * *channels * 2 );
71 mlt_properties_set_data( properties, "audio", *buffer, *channels * data.output_frames_gen * 2, free, NULL );
73 *samples = data.output_frames_gen;
74 *frequency = output_rate;
76 // Convert from floating back to signed 16bit
77 for ( i = 0; i < *samples * *channels; ++i )
79 float sample = output_buffer[ i ];
85 (*buffer)[ i ] = lrint( 32767.0 * sample );
87 (*buffer)[ i ] = lrint( 32768.0 * sample );
91 //fprintf( stderr, "resample_get_audio: %s\n", src_strerror( i ) );
96 /** Filter processing.
99 static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
101 mlt_properties properties = mlt_filter_properties( this );
102 mlt_properties frame_props = mlt_frame_properties( frame );
104 // Propogate the frequency property if supplied
105 if ( mlt_properties_get( properties, "frequency" ) != NULL )
106 mlt_properties_set_int( frame_props, "resample.frequency", mlt_properties_get_int( properties, "frequency" ) );
108 // Propogate the other properties
109 mlt_properties_set_int( frame_props, "resample.channels", mlt_properties_get_int( properties, "channels" ) );
110 mlt_properties_set_data( frame_props, "resample.state", mlt_properties_get_data( properties, "state", NULL ), 0, NULL, NULL );
111 mlt_properties_set_data( frame_props, "resample.input_buffer", mlt_properties_get_data( properties, "input_buffer", NULL ), 0, NULL, NULL );
112 mlt_properties_set_data( frame_props, "resample.output_buffer", mlt_properties_get_data( properties, "output_buffer", NULL ), 0, NULL, NULL );
114 // Backup the original get_audio (it's still needed)
115 mlt_properties_set_data( frame_props, "resample.get_audio", frame->get_audio, 0, NULL, NULL );
117 // Override the get_audio method
118 frame->get_audio = resample_get_audio;
123 /** Constructor for the filter.
126 mlt_filter filter_resample_init( char *arg )
128 mlt_filter this = calloc( sizeof( struct mlt_filter_s ), 1 );
129 if ( this != NULL && mlt_filter_init( this, NULL ) == 0 )
132 SRC_STATE *state = src_new( RESAMPLE_TYPE, 2 /* channels */, &error );
135 this->process = filter_process;
137 mlt_properties_set_int( mlt_filter_properties( this ), "frequency", atoi( arg ) );
138 mlt_properties_set_int( mlt_filter_properties( this ), "channels", 2 );
139 mlt_properties_set_data( mlt_filter_properties( this ), "state", state, 0, (mlt_destructor)src_delete, NULL );
140 mlt_properties_set_data( mlt_filter_properties( this ), "input_buffer",
141 malloc( BUFFER_LEN ), BUFFER_LEN, free, NULL );
142 mlt_properties_set_data( mlt_filter_properties( this ), "output_buffer",
143 malloc( BUFFER_LEN ), BUFFER_LEN, free, NULL );
147 //fprintf( stderr, "filter_resample_init: %s\n", src_strerror( error ) );