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 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 "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         // Restore the original get_audio
  42         frame->get_audio = mlt_properties_get_data( properties, "channelcopy.get_audio", NULL );
  43
  44         // Get the producer's audio
  45         mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
  46
  47         // Duplicate channels as necessary
  48         {
  49                 int size = *channels * *samples * 2;
  50                 int16_t *new_buffer = mlt_pool_alloc( size );
  51
  52                 mlt_properties_set_data( properties, "audio", new_buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
  53
  54                 // Duplicate the existing channels
  55                 for ( i = 0; i < *samples; i++ )
  56                 {
  57                         for ( j = 0; j < *channels; j++ )
  58                         {
  59                                 new_buffer[ ( i * *channels ) + j ] = (*buffer)[ ( i * *channels ) + ( j == to ? from : j ) ];
  60                         }
  61                 }
  62                 *buffer = new_buffer;
  63         }
  64         return 0;
  65 }
  66
  67 /** Filter processing.
  68 */
  69
  70 static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
  71 {
  72         mlt_properties properties = MLT_FILTER_PROPERTIES( this );
  73         mlt_properties frame_props = MLT_FRAME_PROPERTIES( frame );
  74
  75         // Propogate the parameters
  76         mlt_properties_set_int( frame_props, "channelcopy.to", mlt_properties_get_int( properties, "to" ) );
  77         mlt_properties_set_int( frame_props, "channelcopy.from", mlt_properties_get_int( properties, "from" ) );
  78
  79         // Backup the original get_audio (it's still needed)
  80         mlt_properties_set_data( frame_props, "channelcopy.get_audio", frame->get_audio, 0, NULL, NULL );
  81
  82         // Override the get_audio method
  83         frame->get_audio = filter_get_audio;
  84
  85         return frame;
  86 }
  87
  88 /** Constructor for the filter.
  89 */
  90
  91 mlt_filter filter_channelcopy_init( char *arg )
  92 {
  93         mlt_filter this = mlt_filter_new( );
  94         if ( this != NULL )
  95         {
  96                 this->process = filter_process;
  97                 if ( arg != NULL )
  98                         mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "to", atoi( arg ) );
  99                 else
 100                         mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "to", 1 );
 101         }
 102         return this;
 103 }