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 <framework/mlt_filter.h>
  22 #include <framework/mlt_frame.h>
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #define __USE_ISOC99 1
  27 #include <math.h>
  28
  29 /** Get the audio.
  30 */
  31
  32 static int filter_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
  33 {
  34         // Get the properties of the a frame
  35         mlt_properties properties = MLT_FRAME_PROPERTIES( frame );
  36         int i, j;
  37         int from = mlt_properties_get_int( properties, "channelcopy.from" );
  38         int to = mlt_properties_get_int( properties, "channelcopy.to" );
  39
  40         // Get the producer's audio
  41         mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
  42
  43         // Duplicate channels as necessary
  44         {
  45                 int size = *channels * *samples * 2;
  46                 int16_t *new_buffer = mlt_pool_alloc( size );
  47
  48                 mlt_properties_set_data( properties, "audio", new_buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
  49
  50                 // Duplicate the existing channels
  51                 for ( i = 0; i < *samples; i++ )
  52                 {
  53                         for ( j = 0; j < *channels; j++ )
  54                         {
  55                                 new_buffer[ ( i * *channels ) + j ] = (*buffer)[ ( i * *channels ) + ( j == to ? from : j ) ];
  56                         }
  57                 }
  58                 *buffer = new_buffer;
  59         }
  60         return 0;
  61 }
  62
  63 /** Filter processing.
  64 */
  65
  66 static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
  67 {
  68         mlt_properties properties = MLT_FILTER_PROPERTIES( this );
  69         mlt_properties frame_props = MLT_FRAME_PROPERTIES( frame );
  70
  71         // Propogate the parameters
  72         mlt_properties_set_int( frame_props, "channelcopy.to", mlt_properties_get_int( properties, "to" ) );
  73         mlt_properties_set_int( frame_props, "channelcopy.from", mlt_properties_get_int( properties, "from" ) );
  74
  75         // Override the get_audio method
  76         mlt_frame_push_audio( frame, filter_get_audio );
  77
  78         return frame;
  79 }
  80
  81 /** Constructor for the filter.
  82 */
  83
  84 mlt_filter filter_channelcopy_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg )
  85 {
  86         mlt_filter this = mlt_filter_new( );
  87         if ( this != NULL )
  88         {
  89                 this->process = filter_process;
  90                 if ( arg != NULL )
  91                         mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "to", atoi( arg ) );
  92                 else
  93                         mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "to", 1 );
  94         }
  95         return this;
  96 }