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mlt/src/modules/core/filter_channelcopy.c

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2.9 KiB

/*
* filter_channelcopy.c -- copy one audio channel to another
* Copyright (C) 2003-2004 Ushodaya Enterprises Limited
* Author: Dan Dennedy <dan@dennedy.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "filter_channelcopy.h"
#include <framework/mlt_frame.h>
#include <stdio.h>
#include <stdlib.h>
#define __USE_ISOC99 1
#include <math.h>
/** Get the audio.
*/
static int filter_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
{
// Get the properties of the a frame
mlt_properties properties = MLT_FRAME_PROPERTIES( frame );
int i, j;
int from = mlt_properties_get_int( properties, "channelcopy.from" );
int to = mlt_properties_get_int( properties, "channelcopy.to" );
// Get the producer's audio
mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
// Duplicate channels as necessary
{
int size = *channels * *samples * 2;
int16_t *new_buffer = mlt_pool_alloc( size );
mlt_properties_set_data( properties, "audio", new_buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
// Duplicate the existing channels
for ( i = 0; i < *samples; i++ )
{
for ( j = 0; j < *channels; j++ )
{
new_buffer[ ( i * *channels ) + j ] = (*buffer)[ ( i * *channels ) + ( j == to ? from : j ) ];
}
}
*buffer = new_buffer;
}
return 0;
}
/** Filter processing.
*/
static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
{
mlt_properties properties = MLT_FILTER_PROPERTIES( this );
mlt_properties frame_props = MLT_FRAME_PROPERTIES( frame );
// Propogate the parameters
mlt_properties_set_int( frame_props, "channelcopy.to", mlt_properties_get_int( properties, "to" ) );
mlt_properties_set_int( frame_props, "channelcopy.from", mlt_properties_get_int( properties, "from" ) );
// Override the get_audio method
mlt_frame_push_audio( frame, filter_get_audio );
return frame;
}
/** Constructor for the filter.
*/
mlt_filter filter_channelcopy_init( char *arg )
{
mlt_filter this = mlt_filter_new( );
if ( this != NULL )
{
this->process = filter_process;
if ( arg != NULL )
mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "to", atoi( arg ) );
else
mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "to", 1 );
}
return this;
}