research.m1stereo.tv/gitweb/ - melted/blob - src/modules/core/filter_channelcopy.c

   1 /*
   2  * filter_channelcopy.c -- copy one audio channel to another
   3  * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
   4  * Author: Dan Dennedy <dan@dennedy.org>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library 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 GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "filter_channelcopy.h"
  22
  23 #include <framework/mlt_frame.h>
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #define __USE_ISOC99 1
  28 #include <math.h>
  29
  30 /** Get the audio.
  31 */
  32
  33 static int filter_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
  34 {
  35         // Get the properties of the a frame
  36         mlt_properties properties = MLT_FRAME_PROPERTIES( frame );
  37         int i, j;
  38         int from = mlt_properties_get_int( properties, "channelcopy.from" );
  39         int to = mlt_properties_get_int( properties, "channelcopy.to" );
  40
  41         // Get the producer's audio
  42         mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
  43
  44         // Duplicate channels as necessary
  45         {
  46                 int size = *channels * *samples * 2;
  47                 int16_t *new_buffer = mlt_pool_alloc( size );
  48
  49                 mlt_properties_set_data( properties, "audio", new_buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
  50
  51                 // Duplicate the existing channels
  52                 for ( i = 0; i < *samples; i++ )
  53                 {
  54                         for ( j = 0; j < *channels; j++ )
  55                         {
  56                                 new_buffer[ ( i * *channels ) + j ] = (*buffer)[ ( i * *channels ) + ( j == to ? from : j ) ];
  57                         }
  58                 }
  59                 *buffer = new_buffer;
  60         }
  61         return 0;
  62 }
  63
  64 /** Filter processing.
  65 */
  66
  67 static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
  68 {
  69         mlt_properties properties = MLT_FILTER_PROPERTIES( this );
  70         mlt_properties frame_props = MLT_FRAME_PROPERTIES( frame );
  71
  72         // Propogate the parameters
  73         mlt_properties_set_int( frame_props, "channelcopy.to", mlt_properties_get_int( properties, "to" ) );
  74         mlt_properties_set_int( frame_props, "channelcopy.from", mlt_properties_get_int( properties, "from" ) );
  75
  76         // Override the get_audio method
  77         mlt_frame_push_audio( frame, filter_get_audio );
  78
  79         return frame;
  80 }
  81
  82 /** Constructor for the filter.
  83 */
  84
  85 mlt_filter filter_channelcopy_init( char *arg )
  86 {
  87         mlt_filter this = mlt_filter_new( );
  88         if ( this != NULL )
  89         {
  90                 this->process = filter_process;
  91                 if ( arg != NULL )
  92                         mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "to", atoi( arg ) );
  93                 else
  94                         mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "to", 1 );
  95         }
  96         return this;
  97 }