2 * transition_composite.c -- compose one image over another using alpha channel
3 * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
4 * Author: Dan Dennedy <dan@dennedy.org>
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 "transition_composite.h"
22 #include <framework/mlt_frame.h>
39 /** Parse a geometry property string.
42 static void geometry_parse( struct geometry_s *geometry, struct geometry_s *defaults, char *property )
44 // Assign from defaults if available
45 if ( defaults != NULL )
47 geometry->x = defaults->x;
48 geometry->y = defaults->y;
49 geometry->w = defaults->w;
50 geometry->h = defaults->h;
51 geometry->mix = defaults->mix;
58 // Parse the geomtry string
59 if ( property != NULL )
60 sscanf( property, "%f,%f:%fx%f:%f", &geometry->x, &geometry->y, &geometry->w, &geometry->h, &geometry->mix );
63 /** Calculate real geometry.
66 static void geometry_calculate( struct geometry_s *output, struct geometry_s *in, struct geometry_s *out, float position )
68 // Calculate this frames geometry
69 output->x = in->x + ( out->x - in->x ) * position;
70 output->y = in->y + ( out->y - in->y ) * position;
71 output->w = in->w + ( out->w - in->w ) * position;
72 output->h = in->h + ( out->h - in->h ) * position;
73 output->mix = in->mix + ( out->mix - in->mix ) * position;
76 /** Calculate the position for this frame.
79 static float position_calculate( mlt_transition this, mlt_frame frame )
81 // Get the in and out position
82 mlt_position in = mlt_transition_get_in( this );
83 mlt_position out = mlt_transition_get_out( this );
85 // Get the position of the frame
86 mlt_position position = mlt_frame_get_position( frame );
89 return ( float )( position - in ) / ( float )( out - in + 1 );
92 /** Composite function.
95 static int composite_yuv( uint8_t *p_dest, mlt_image_format format_dest, int width_dest, int height_dest, mlt_frame that, struct geometry_s geometry )
102 int x_src = 0, y_src = 0;
104 mlt_image_format format_src = format_dest;
105 int x = ( int )( ( float )width_dest * geometry.x / 100 );
106 int y = ( int )( ( float )height_dest * geometry.y / 100 );
107 float weight = geometry.mix / 100;
108 int width_src = ( int )( ( float )width_dest * geometry.w / 100 );
109 int height_src = ( int )( ( float )height_dest * geometry.h / 100 );
113 // optimization point - no work to do
114 if ( ( x < 0 && -x >= width_src ) || ( y < 0 && -y >= height_src ) )
117 format_src = mlt_image_yuv422;
118 format_dest = mlt_image_yuv422;
120 mlt_frame_get_image( that, &p_src, &format_src, &width_src, &height_src, 1 /* writable */ );
122 stride_src = width_src * 2;
123 stride_dest = width_dest * 2;
125 // crop overlay off the left edge of frame
133 // crop overlay beyond right edge of frame
134 else if ( x + width_src > width_dest )
135 width_src = width_dest - x;
137 // crop overlay off the top edge of the frame
143 // crop overlay below bottom edge of frame
144 else if ( y + height_src > height_dest )
145 height_src = height_dest - y;
147 // offset pointer into overlay buffer based on cropping
148 p_src += x_src * 2 + y_src * stride_src;
150 // offset pointer into frame buffer based upon positive, even coordinates only!
151 p_dest += ( x < 0 ? 0 : x ) * 2 + ( y < 0 ? 0 : y ) * stride_dest;
153 // Get the alpha channel of the overlay
154 uint8_t *p_alpha = mlt_frame_get_alpha_mask( that );
156 // offset pointer into alpha channel based upon cropping
158 p_alpha += x_src + y_src * stride_src / 2;
163 uint8_t *z = p_alpha;
170 // now do the compositing only to cropped extents
171 for ( i = 0; i < height_src; i++ )
178 for ( j = 0; j < width_src; j ++ )
182 a = ( z == NULL ) ? 255 : *z ++;
183 value = ( weight * ( float ) a / 255.0 );
184 *o ++ = (uint8_t)( Y * value + *q++ * ( 1 - value ) );
185 *o ++ = (uint8_t)( UV * value + *q++ * ( 1 - value ) );
189 p_dest += stride_dest;
191 p_alpha += stride_src / 2;
201 static int transition_get_image( mlt_frame a_frame, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
203 // Get the b frame from the stack
204 mlt_frame b_frame = mlt_frame_pop_frame( a_frame );
206 // Get the image from the a frame
207 mlt_frame_get_image( a_frame, image, format, width, height, 1 );
209 if ( b_frame != NULL )
211 // Get the properties of the b frame
212 mlt_properties b_props = mlt_frame_properties( b_frame );
214 // Get the transition from the b frame
215 mlt_transition this = mlt_properties_get_data( b_props, "transition_composite", NULL );
217 // Get the properties from the transition
218 mlt_properties properties = mlt_transition_properties( this );
220 // Structures for geometry
221 struct geometry_s result;
222 struct geometry_s start;
223 struct geometry_s end;
225 // Calculate the position
226 float position = position_calculate( this, a_frame );
228 // Now parse the geometries
229 geometry_parse( &start, NULL, mlt_properties_get( properties, "start" ) );
230 geometry_parse( &end, &start, mlt_properties_get( properties, "end" ) );
232 // Do the calculation
233 geometry_calculate( &result, &start, &end, position );
235 // Composite the b_frame on the a_frame
236 composite_yuv( *image, *format, *width, *height, b_frame, result );
242 /** Composition transition processing.
245 static mlt_frame composite_process( mlt_transition this, mlt_frame a_frame, mlt_frame b_frame )
247 // Propogate the transition properties to the b frame
248 mlt_properties b_props = mlt_frame_properties( b_frame );
249 mlt_properties_set_data( b_props, "transition_composite", this, 0, NULL, NULL );
250 mlt_frame_push_get_image( a_frame, transition_get_image );
251 mlt_frame_push_frame( a_frame, b_frame );
255 /** Constructor for the filter.
258 mlt_transition transition_composite_init( char *arg )
260 mlt_transition this = calloc( sizeof( struct mlt_transition_s ), 1 );
261 if ( this != NULL && mlt_transition_init( this, NULL ) == 0 )
263 this->process = composite_process;
264 mlt_properties_set( mlt_transition_properties( this ), "start", arg != NULL ? arg : "85,5:10x10" );
265 mlt_properties_set( mlt_transition_properties( this ), "end", "" );