2 * producer_noise.c -- noise generating producer
3 * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
4 * Author: Charles Yates <charles.yates@pandora.be>
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.
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.
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.
21 #include "producer_noise.h"
22 #include <framework/mlt_frame.h>
23 #include <framework/mlt_pool.h>
29 /** Random number generator
32 static unsigned int seed_x
= 521288629;
33 static unsigned int seed_y
= 362436069;
35 static unsigned inline int fast_rand( )
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 ) );
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 );
50 mlt_producer
producer_noise_init( void *arg
)
52 // Create a new producer object
53 mlt_producer
this = mlt_producer_new( );
55 // Initialise the producer
58 // Callback registration
59 this->get_frame
= producer_get_frame
;
60 this->close
= ( mlt_destructor
)producer_close
;
66 static int producer_get_image( mlt_frame frame
, uint8_t **buffer
, mlt_image_format
*format
, int *width
, int *height
, int writable
)
68 // Obtain properties of frame
69 mlt_properties properties
= MLT_FRAME_PROPERTIES( frame
);
71 // Calculate the size of the image
72 int size
= *width
* *height
* 2;
74 // Set the format being returned
75 *format
= mlt_image_yuv422
;
78 *buffer
= mlt_pool_alloc( size
);
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
);
85 // Before we write to the image, make sure we have one
86 if ( *buffer
!= NULL
)
88 // Calculate the end of the buffer
89 uint8_t *p
= *buffer
+ *width
* *height
* 2;
91 // Value to hold a random number
94 // Generate random noise
95 while ( p
!= *buffer
)
97 value
= fast_rand( ) & 0xff;
99 *( -- p
) = value
< 16 ?
16 : value
> 240 ?
240 : value
;
106 static int producer_get_audio( mlt_frame frame
, int16_t **buffer
, mlt_audio_format
*format
, int *frequency
, int *channels
, int *samples
)
108 // Get the frame properties
109 mlt_properties properties
= MLT_FRAME_PROPERTIES( frame
);
113 // Correct the returns if necessary
114 *samples
= *samples
<= 0 ?
1920 : *samples
;
115 *channels
= *channels
<= 0 ?
2 : *channels
;
116 *frequency
= *frequency
<= 0 ?
48000 : *frequency
;
118 // Calculate the size of the buffer
119 size
= *samples
* *channels
* sizeof( int16_t );
121 // Allocate the buffer
122 *buffer
= mlt_pool_alloc( size
);
124 // Make sure we got one and fill it
125 if ( *buffer
!= NULL
)
127 int16_t *p
= *buffer
+ size
/ 2;
128 while ( p
!= *buffer
)
129 *( -- p
) = fast_rand( ) & 0x0f00;
132 // Set the buffer for destruction
133 mlt_properties_set_data( properties
, "audio", *buffer
, size
, ( mlt_destructor
)mlt_pool_release
, NULL
);
138 static int producer_get_frame( mlt_producer
this, mlt_frame_ptr frame
, int index
)
141 *frame
= mlt_frame_init( );
143 // Check that we created a frame and initialise it
144 if ( *frame
!= NULL
)
146 // Obtain properties of frame
147 mlt_properties properties
= MLT_FRAME_PROPERTIES( *frame
);
149 // Aspect ratio is whatever it needs to be
150 mlt_properties_set_double( properties
, "aspect_ratio", 0 );
152 // Set producer-specific frame properties
153 mlt_properties_set_int( properties
, "progressive", 1 );
155 // Update timecode on the frame we're creating
156 mlt_frame_set_position( *frame
, mlt_producer_position( this ) );
158 // Push the get_image method
159 mlt_frame_push_get_image( *frame
, producer_get_image
);
162 mlt_frame_push_audio( *frame
, producer_get_audio
);
165 // Calculate the next timecode
166 mlt_producer_prepare_next( this );
171 static void producer_close( mlt_producer
this )
174 mlt_producer_close( this );