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
32 static unsigned int seed_x = 521288629;
33 static unsigned int seed_y = 362436069;
35 static inline unsigned 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( mlt_profile profile, mlt_service_type type, const char *id, char *arg )
52 // Create a new producer object
53 mlt_producer this = mlt_producer_new( profile );
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 // Choose suitable out values if nothing specific requested
70 *width = mlt_service_profile( MLT_PRODUCER_SERVICE( mlt_frame_get_original_producer( frame ) ) )->width;
72 *height = mlt_service_profile( MLT_PRODUCER_SERVICE( mlt_frame_get_original_producer( frame ) ) )->height;
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_frame_set_image( frame, *buffer, size, mlt_pool_release );
86 // Before we write to the image, make sure we have one
87 if ( *buffer != NULL )
89 // Calculate the end of the buffer
90 uint8_t *p = *buffer + *width * *height * 2;
92 // Value to hold a random number
95 // Generate random noise
96 while ( p != *buffer )
98 value = fast_rand( ) & 0xff;
100 *( -- p ) = value < 16 ? 16 : value > 240 ? 240 : value;
107 static int producer_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
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 *format = mlt_audio_s16;
117 // Calculate the size of the buffer
118 size = *samples * *channels * sizeof( int16_t );
120 // Allocate the buffer
121 *buffer = mlt_pool_alloc( size );
123 // Make sure we got one and fill it
124 if ( *buffer != NULL )
126 int16_t *p = *buffer + size / 2;
127 while ( p != *buffer )
128 *( -- p ) = fast_rand( ) & 0x0f00;
131 // Set the buffer for destruction
132 mlt_frame_set_audio( frame, *buffer, *format, size, mlt_pool_release );
137 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index )
140 *frame = mlt_frame_init( MLT_PRODUCER_SERVICE( this ) );
142 // Check that we created a frame and initialise it
143 if ( *frame != NULL )
145 // Obtain properties of frame
146 mlt_properties properties = MLT_FRAME_PROPERTIES( *frame );
148 // Aspect ratio is whatever it needs to be
149 mlt_profile profile = mlt_service_profile( MLT_PRODUCER_SERVICE( this ) );
150 mlt_properties_set_double( properties, "aspect_ratio", mlt_profile_sar( profile ) );
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 );