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

   1 /*
   2  * producer_noise.c -- noise generating producer
   3  * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
   4  * Author: Charles Yates <charles.yates@pandora.be>
   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 "producer_noise.h"
  22 #include <framework/mlt_frame.h>
  23 #include <framework/mlt_pool.h>
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28
  29 /** Random number generator
  30 */
  31
  32 static unsigned int seed_x = 521288629;
  33 static unsigned int seed_y = 362436069;
  34
  35 static inline unsigned int fast_rand( )
  36 {
  37    static unsigned int a = 18000, b = 30903;
  38    seed_x = a * ( seed_x & 65535 ) + ( seed_x >> 16 );
  39    seed_y = b * ( seed_y & 65535 ) + ( seed_y >> 16 );
  40    return ( ( seed_x << 16 ) + ( seed_y & 65535 ) );
  41 }
  42
  43 // Foward declarations
  44 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index );
  45 static void producer_close( mlt_producer this );
  46
  47 /** Initialise.
  48 */
  49
  50 mlt_producer producer_noise_init( void *arg )
  51 {
  52         // Create a new producer object
  53         mlt_producer this = mlt_producer_new( );
  54
  55         // Initialise the producer
  56         if ( this != NULL )
  57         {
  58                 // Callback registration
  59                 this->get_frame = producer_get_frame;
  60                 this->close = ( mlt_destructor )producer_close;
  61         }
  62
  63         return this;
  64 }
  65
  66 static int producer_get_image( mlt_frame frame, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
  67 {
  68         // Obtain properties of frame
  69         mlt_properties properties = MLT_FRAME_PROPERTIES( frame );
  70
  71         // Calculate the size of the image
  72         int size = *width * *height * 2;
  73
  74         // Set the format being returned
  75         *format = mlt_image_yuv422;
  76
  77         // Allocate the image
  78         *buffer = mlt_pool_alloc( size );
  79
  80         // Update the frame
  81         mlt_properties_set_data( properties, "image", *buffer, size, mlt_pool_release, NULL );
  82         mlt_properties_set_int( properties, "width", *width );
  83         mlt_properties_set_int( properties, "height", *height );
  84
  85         // Before we write to the image, make sure we have one
  86         if ( *buffer != NULL )
  87         {
  88                 // Calculate the end of the buffer
  89                 uint8_t *p = *buffer + *width * *height * 2;
  90
  91                 // Value to hold a random number
  92                 uint32_t value;
  93
  94                 // Generate random noise
  95                 while ( p != *buffer )
  96                 {
  97                         value = fast_rand( ) & 0xff;
  98                         *( -- p ) = 128;
  99                         *( -- p ) = value < 16 ? 16 : value > 240 ? 240 : value;
 100                 }
 101         }
 102
 103         return 0;
 104 }
 105
 106 static int producer_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
 107 {
 108         // Get the frame properties
 109         mlt_properties properties = MLT_FRAME_PROPERTIES( frame );
 110
 111         int size = 0;
 112
 113         // Correct the returns if necessary
 114         *samples = *samples <= 0 ? 1920 : *samples;
 115         *channels = *channels <= 0 ? 2 : *channels;
 116         *frequency = *frequency <= 0 ? 48000 : *frequency;
 117
 118         // Calculate the size of the buffer
 119         size = *samples * *channels * sizeof( int16_t );
 120
 121         // Allocate the buffer
 122         *buffer = mlt_pool_alloc( size );
 123
 124         // Make sure we got one and fill it
 125         if ( *buffer != NULL )
 126         {
 127                 int16_t *p = *buffer + size / 2;
 128                 while ( p != *buffer )
 129                         *( -- p ) = fast_rand( ) & 0x0f00;
 130         }
 131
 132         // Set the buffer for destruction
 133         mlt_properties_set_data( properties, "audio", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
 134
 135         return 0;
 136 }
 137
 138 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index )
 139 {
 140         // Generate a frame
 141         *frame = mlt_frame_init( );
 142
 143         // Check that we created a frame and initialise it
 144         if ( *frame != NULL )
 145         {
 146                 // Obtain properties of frame
 147                 mlt_properties properties = MLT_FRAME_PROPERTIES( *frame );
 148
 149                 // Aspect ratio is whatever it needs to be
 150                 mlt_properties_set_double( properties, "aspect_ratio", 0 );
 151
 152                 // Set producer-specific frame properties
 153                 mlt_properties_set_int( properties, "progressive", 1 );
 154
 155                 // Update timecode on the frame we're creating
 156                 mlt_frame_set_position( *frame, mlt_producer_position( this ) );
 157
 158                 // Push the get_image method
 159                 mlt_frame_push_get_image( *frame, producer_get_image );
 160
 161                 // Specify the audio
 162                 mlt_frame_push_audio( *frame, producer_get_audio );
 163         }
 164
 165         // Calculate the next timecode
 166         mlt_producer_prepare_next( this );
 167
 168         return 0;
 169 }
 170
 171 static void producer_close( mlt_producer this )
 172 {
 173         this->close = NULL;
 174         mlt_producer_close( this );
 175         free( this );
 176 }
 177