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
);
46 int channels_avail
= *channels
;
49 if ( output_rate
== 0 )
50 output_rate
= *frequency
;
52 // Restore the original get_audio
53 frame
->get_audio
= mlt_properties_get_data( properties
, "resample.get_audio", NULL
);
55 // Get the producer's audio
56 mlt_frame_get_audio( frame
, buffer
, format
, frequency
, &channels_avail
, samples
);
58 // Duplicate channels as necessary
59 if ( channels_avail
< *channels
)
61 int size
= *channels
* *samples
* 2;
62 int16_t *new_buffer
= mlt_pool_alloc( size
);
64 mlt_properties_set_data( properties
, "audio", new_buffer
, size
, ( mlt_destructor
)mlt_pool_release
, NULL
);
66 // Duplicate the existing channels
67 for ( i
= 0; i
< *samples
; i
++ )
70 for ( j
= 0; j
< *channels
; j
++ )
72 new_buffer
[ ( i
* *channels
) + j
] = (*buffer
)[ ( i
* channels_avail
) + k
];
73 k
= ( k
+ 1 ) % channels_avail
;
80 // Return now if now work to do
81 if ( output_rate
== *frequency
)
84 //fprintf( stderr, "resample_get_audio: input_rate %d output_rate %d\n", *frequency, output_rate );
86 // Convert to floating point
87 for ( i
= 0; i
< *samples
* *channels
; ++i
)
88 input_buffer
[ i
] = ( float )( (*buffer
)[ i
] ) / 32768;
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
);
100 if ( data
.output_frames_gen
> *samples
)
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
);
105 *samples
= data
.output_frames_gen
;
106 *frequency
= output_rate
;
108 // Convert from floating back to signed 16bit
109 for ( i
= 0; i
< *samples
* *channels
; ++i
)
111 float sample
= output_buffer
[ i
];
117 (*buffer
)[ i
] = lrint( 32767.0 * sample
);
119 (*buffer
)[ i
] = lrint( 32768.0 * sample
);
123 fprintf( stderr
, "resample_get_audio: %s %d,%d,%d\n", src_strerror( i
), *frequency
, *samples
, output_rate
);
128 /** Filter processing.
131 static mlt_frame
filter_process( mlt_filter
this, mlt_frame frame
)
133 mlt_properties properties
= mlt_filter_properties( this );
134 mlt_properties frame_props
= mlt_frame_properties( frame
);
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" ) );
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
);
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
);
149 // Override the get_audio method
150 frame
->get_audio
= resample_get_audio
;
155 /** Constructor for the filter.
158 mlt_filter
filter_resample_init( char *arg
)
160 mlt_filter
this = mlt_filter_new( );
164 SRC_STATE
*state
= src_new( RESAMPLE_TYPE
, 2 /* channels */, &error
);
167 void *input_buffer
= mlt_pool_alloc( BUFFER_LEN
);
168 void *output_buffer
= mlt_pool_alloc( BUFFER_LEN
);
169 this->process
= filter_process
;
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
);
179 fprintf( stderr
, "filter_resample_init: %s\n", src_strerror( error
) );