research.m1stereo.tv/gitweb/ - melted/blob - mlt/src/framework/mlt_tractor.c

   1 /*
   2  * mlt_tractor.c -- tractor service class
   3  * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
   4  * Author: Charles Yates <charles.yates@pandora.be>
   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 "config.h"
  22
  23 #include "mlt_tractor.h"
  24 #include "mlt_frame.h"
  25
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28
  29 /** Private structure.
  30 */
  31
  32 struct mlt_tractor_s
  33 {
  34         struct mlt_service_s parent;
  35         mlt_service producer;
  36 };
  37
  38 /** Forward references to static methods.
  39 */
  40
  41 static int service_get_frame( mlt_service this, mlt_frame_ptr frame, int track );
  42
  43 /** Constructor for the tractor.
  44
  45         TODO: thread this service...
  46 */
  47
  48 mlt_tractor mlt_tractor_init( )
  49 {
  50         mlt_tractor this = calloc( sizeof( struct mlt_tractor_s ), 1 );
  51         if ( this != NULL )
  52         {
  53                 mlt_service service = &this->parent;
  54                 if ( mlt_service_init( service, this ) == 0 )
  55                 {
  56                         service->get_frame = service_get_frame;
  57                 }
  58                 else
  59                 {
  60                         free( this );
  61                         this = NULL;
  62                 }
  63         }
  64         return this;
  65 }
  66
  67 /** Get the service object associated to the tractor.
  68 */
  69
  70 mlt_service mlt_tractor_service( mlt_tractor this )
  71 {
  72         return &this->parent;
  73 }
  74
  75 /** Connect the tractor.
  76 */
  77
  78 int mlt_tractor_connect( mlt_tractor this, mlt_service producer )
  79 {
  80         int ret = mlt_service_connect_producer( &this->parent, producer, 0 );
  81
  82         if ( ret == 0 )
  83         {
  84                 // This is the producer we're going to connect to
  85                 this->producer = producer;
  86         }
  87
  88         return ret;
  89 }
  90
  91 /** Get the next frame.
  92
  93         TODO: This should be reading a pump being populated by the thread...
  94 */
  95
  96 static int service_get_frame( mlt_service parent, mlt_frame_ptr frame, int track )
  97 {
  98         mlt_tractor this = parent->child;
  99
 100         // We only respond to the first track requests
 101         if ( track == 0 && this->producer != NULL )
 102         {
 103                 int i = 0;
 104                 int looking = 1;
 105                 int done = 0;
 106                 mlt_frame temp;
 107
 108                 // Loop through each of the tracks we're harvesting
 109                 for ( i = 0; !done; i ++ )
 110                 {
 111                         // Get a frame from the producer
 112                         mlt_service_get_frame( this->producer, &temp, i );
 113
 114                         // Check for last track
 115                         done = mlt_properties_get_int( mlt_frame_properties( temp ), "last_track" );
 116
 117                         // Handle the frame
 118                         if ( done && looking )
 119                         {
 120                                 // Use this as output if we don't have one already
 121                                 *frame = temp;
 122                         }
 123                         else if ( !mlt_frame_is_test_card( temp ) && looking )
 124                         {
 125                                 // This is the one we want and we can stop looking
 126                                 *frame = temp;
 127                                 looking = 0;
 128                         }
 129                         else
 130                         {
 131                                 // We discard all other frames
 132                                 mlt_frame_close( temp );
 133                         }
 134                 }
 135
 136                 // Indicate our found status
 137                 return 0;
 138         }
 139         else
 140         {
 141                 // Generate a test card
 142                 *frame = mlt_frame_init( );
 143                 return 0;
 144         }
 145 }
 146
 147 /** Close the tractor.
 148 */
 149
 150 void mlt_tractor_close( mlt_tractor this )
 151 {
 152         mlt_service_close( &this->parent );
 153         free( this );
 154 }
 155