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 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.
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.
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
21 #include <framework/mlt_producer.h>
22 #include <framework/mlt_frame.h>
23 #include <framework/mlt_pool.h>
29 /** Random number generator
38 static void init_seed( rand_seed* seed, int init )
40 // Use the initial value to initialize the seed to arbitrary values.
41 // This causes the algorithm to produce consistent results each time for the same frame number.
42 seed->x = 521288629 + init - ( init << 16 );
43 seed->y = 362436069 - init + ( init << 16 );
46 static inline unsigned int fast_rand( rand_seed* seed )
48 static unsigned int a = 18000, b = 30903;
49 seed->x = a * ( seed->x & 65535 ) + ( seed->x >> 16 );
50 seed->y = b * ( seed->y & 65535 ) + ( seed->y >> 16 );
51 return ( ( seed->x << 16 ) + ( seed->y & 65535 ) );
54 // Foward declarations
55 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index );
56 static void producer_close( mlt_producer this );
61 mlt_producer producer_noise_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg )
63 // Create a new producer object
64 mlt_producer this = mlt_producer_new( profile );
66 // Initialise the producer
69 // Callback registration
70 this->get_frame = producer_get_frame;
71 this->close = ( mlt_destructor )producer_close;
77 static int producer_get_image( mlt_frame frame, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
79 // Choose suitable out values if nothing specific requested
81 *width = mlt_service_profile( MLT_PRODUCER_SERVICE( mlt_frame_get_original_producer( frame ) ) )->width;
83 *height = mlt_service_profile( MLT_PRODUCER_SERVICE( mlt_frame_get_original_producer( frame ) ) )->height;
85 // Calculate the size of the image
86 int size = *width * *height * 2;
88 // Set the format being returned
89 *format = mlt_image_yuv422;
92 *buffer = mlt_pool_alloc( size );
95 mlt_frame_set_image( frame, *buffer, size, mlt_pool_release );
97 // Before we write to the image, make sure we have one
98 if ( *buffer != NULL )
100 // Calculate the end of the buffer
101 uint8_t *p = *buffer + *width * *height * 2;
103 // Value to hold a random number
106 // Initialize seed from the frame number.
108 init_seed( &seed, mlt_frame_get_position( frame ) );
110 // Generate random noise
111 while ( p != *buffer )
113 value = fast_rand( &seed ) & 0xff;
115 *( -- p ) = value < 16 ? 16 : value > 240 ? 240 : value;
122 static int producer_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
126 // Correct the returns if necessary
127 *samples = *samples <= 0 ? 1920 : *samples;
128 *channels = *channels <= 0 ? 2 : *channels;
129 *frequency = *frequency <= 0 ? 48000 : *frequency;
130 *format = mlt_audio_s16;
132 // Calculate the size of the buffer
133 size = *samples * *channels * sizeof( int16_t );
135 // Allocate the buffer
136 *buffer = mlt_pool_alloc( size );
138 // Make sure we got one and fill it
139 if ( *buffer != NULL )
141 int16_t *p = *buffer + size / 2;
143 init_seed( &seed, mlt_frame_get_position( frame ) );
144 while ( p != *buffer )
145 *( -- p ) = fast_rand( &seed ) & 0x0f00;
148 // Set the buffer for destruction
149 mlt_frame_set_audio( frame, *buffer, *format, size, mlt_pool_release );
154 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index )
157 *frame = mlt_frame_init( MLT_PRODUCER_SERVICE( this ) );
159 // Check that we created a frame and initialise it
160 if ( *frame != NULL )
162 // Obtain properties of frame
163 mlt_properties properties = MLT_FRAME_PROPERTIES( *frame );
165 // Aspect ratio is whatever it needs to be
166 mlt_profile profile = mlt_service_profile( MLT_PRODUCER_SERVICE( this ) );
167 mlt_properties_set_double( properties, "aspect_ratio", mlt_profile_sar( profile ) );
169 // Set producer-specific frame properties
170 mlt_properties_set_int( properties, "progressive", 1 );
172 // Update timecode on the frame we're creating
173 mlt_frame_set_position( *frame, mlt_producer_position( this ) );
175 // Push the get_image method
176 mlt_frame_push_get_image( *frame, producer_get_image );
179 mlt_frame_push_audio( *frame, producer_get_audio );
182 // Calculate the next timecode
183 mlt_producer_prepare_next( this );
188 static void producer_close( mlt_producer this )
191 mlt_producer_close( this );