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 // Synthetic - aspect ratio of 1
59 mlt_properties_set_double( mlt_producer_properties( this ), "aspect_ratio", 1 );
61 // Callback registration
62 this->get_frame
= producer_get_frame
;
63 this->close
= ( mlt_destructor
)producer_close
;
69 static int producer_get_image( mlt_frame frame
, uint8_t **buffer
, mlt_image_format
*format
, int *width
, int *height
, int writable
)
71 // Obtain properties of frame
72 mlt_properties properties
= mlt_frame_properties( frame
);
74 // Calculate the size of the image
75 int size
= *width
* *height
* 2;
77 // Set the format being returned
78 *format
= mlt_image_yuv422
;
81 *buffer
= mlt_pool_alloc( size
);
84 mlt_properties_set_data( properties
, "image", *buffer
, size
, mlt_pool_release
, NULL
);
85 mlt_properties_set_int( properties
, "width", *width
);
86 mlt_properties_set_int( properties
, "height", *height
);
88 // Before we write to the image, make sure we have one
89 if ( *buffer
!= NULL
)
91 // Calculate the end of the buffer
92 uint8_t *p
= *buffer
+ *width
* *height
* 2;
94 // Value to hold a random number
97 // Generate random noise
98 while ( p
!= *buffer
)
100 value
= fast_rand( ) & 0xff;
102 *( -- p
) = value
< 16 ?
16 : value
> 240 ?
240 : value
;
109 static int producer_get_audio( mlt_frame frame
, int16_t **buffer
, mlt_audio_format
*format
, int *frequency
, int *channels
, int *samples
)
111 // Get the frame properties
112 mlt_properties properties
= mlt_frame_properties( frame
);
116 // Correct the returns if necessary
117 *samples
= *samples
<= 0 ?
1920 : *samples
;
118 *channels
= *channels
<= 0 ?
2 : *channels
;
119 *frequency
= *frequency
<= 0 ?
48000 : *frequency
;
121 // Calculate the size of the buffer
122 size
= *samples
* *channels
* sizeof( int16_t );
124 // Allocate the buffer
125 *buffer
= mlt_pool_alloc( size
);
127 // Make sure we got one and fill it
128 if ( *buffer
!= NULL
)
130 int16_t *p
= *buffer
+ size
/ 2;
131 while ( p
!= *buffer
)
132 *( -- p
) = fast_rand( ) & 0x0f00;
135 // Set the buffer for destruction
136 mlt_properties_set_data( properties
, "audio", *buffer
, size
, ( mlt_destructor
)mlt_pool_release
, NULL
);
141 static int producer_get_frame( mlt_producer
this, mlt_frame_ptr frame
, int index
)
144 *frame
= mlt_frame_init( );
146 // Check that we created a frame and initialise it
147 if ( *frame
!= NULL
)
149 // Obtain properties of frame
150 mlt_properties properties
= mlt_frame_properties( *frame
);
152 // Obtain properties of producer
153 mlt_properties producer_props
= mlt_producer_properties( this );
155 // Determine if we're producing PAL or NTSC
156 int is_pal
= mlt_properties_get_double( producer_props
, "fps" ) == 25.0;
158 // Aspect ratio is 1?
159 mlt_properties_set_double( properties
, "aspect_ratio", is_pal ?
128.0/117.0 : 72.0/79.0 );
161 // Set producer-specific frame properties
162 mlt_properties_set_int( properties
, "progressive", 1 );
164 // Update timecode on the frame we're creating
165 mlt_frame_set_position( *frame
, mlt_producer_position( this ) );
167 // Push the get_image method
168 mlt_frame_push_get_image( *frame
, producer_get_image
);
171 ( *frame
)->get_audio
= producer_get_audio
;
174 // Calculate the next timecode
175 mlt_producer_prepare_next( this );
180 static void producer_close( mlt_producer
this )
183 mlt_producer_close( this );