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 = 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 );