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 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 "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 unsigned inline 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
  46 /** Initialise.
  47 */
  48
  49 mlt_producer producer_noise_init( void *arg )
  50 {
  51         // Create a new producer object
  52         mlt_producer this = mlt_producer_new( );
  53
  54         // Initialise the producer
  55         if ( this != NULL )
  56         {
  57                 // Callback registration
  58                 this->get_frame = producer_get_frame;
  59         }
  60
  61         return this;
  62 }
  63
  64 static int producer_get_image( mlt_frame frame, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
  65 {
  66         // Obtain properties of frame
  67         mlt_properties properties = mlt_frame_properties( frame );
  68
  69         // Calculate the size of the image
  70         int size = *width * *height * 2;
  71
  72         // Set the format being returned
  73         *format = mlt_image_yuv422;
  74
  75         // Allocate the image
  76         *buffer = mlt_pool_alloc( size );
  77
  78         // Update the frame
  79         mlt_properties_set_data( properties, "image", *buffer, size, mlt_pool_release, NULL );
  80         mlt_properties_set_int( properties, "width", *width );
  81         mlt_properties_set_int( properties, "height", *height );
  82
  83         // Before we write to the image, make sure we have one
  84         if ( *buffer != NULL )
  85         {
  86                 // Calculate the end of the buffer
  87                 uint8_t *p = *buffer + *width * *height * 2;
  88
  89                 // Value to hold a random number
  90                 uint32_t value;
  91
  92                 // Generate random noise
  93                 while ( p != *buffer )
  94                 {
  95                         value = fast_rand( ) & 0xff;
  96                         *( -- p ) = 128;
  97                         *( -- p ) = value < 16 ? 16 : value > 240 ? 240 : value;
  98                 }
  99         }
 100
 101         return 0;
 102 }
 103
 104 static int producer_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
 105 {
 106         // Get the frame properties
 107         mlt_properties properties = mlt_frame_properties( frame );
 108
 109         int size = 0;
 110
 111         // Correct the returns if necessary
 112         *samples = *samples <= 0 ? 1920 : *samples;
 113         *channels = *channels <= 0 ? 2 : *channels;
 114         *frequency = *frequency <= 0 ? 48000 : *frequency;
 115
 116         // Calculate the size of the buffer
 117         size = *samples * *channels * sizeof( int16_t );
 118
 119         // Allocate the buffer
 120         *buffer = mlt_pool_alloc( size );
 121
 122         // Make sure we got one and fill it
 123         if ( *buffer != NULL )
 124         {
 125                 int16_t *p = *buffer + size / 2;
 126                 while ( p != *buffer )
 127                         *( -- p ) = fast_rand( ) & 0xff;
 128         }
 129
 130         // Set the buffer for destruction
 131         mlt_properties_set_data( properties, "audio", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
 132
 133         return 0;
 134 }
 135
 136 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index )
 137 {
 138         // Generate a frame
 139         *frame = mlt_frame_init( );
 140
 141         // Check that we created a frame and initialise it
 142         if ( *frame != NULL )
 143         {
 144                 // Obtain properties of frame
 145                 mlt_properties properties = mlt_frame_properties( *frame );
 146
 147                 // Aspect ratio is 1?
 148                 mlt_properties_set_double( properties, "aspect_ratio", 1.0 );
 149
 150                 // Set producer-specific frame properties
 151                 mlt_properties_set_int( properties, "progressive", 1 );
 152
 153                 // Update timecode on the frame we're creating
 154                 mlt_frame_set_position( *frame, mlt_producer_position( this ) );
 155
 156                 // Push the get_image method
 157                 mlt_frame_push_get_image( *frame, producer_get_image );
 158
 159                 // Specify the audio
 160                 ( *frame )->get_audio = producer_get_audio;
 161         }
 162
 163         // Calculate the next timecode
 164         mlt_producer_prepare_next( this );
 165
 166         return 0;
 167 }
 168
 169