research.m1stereo.tv/gitweb/ - melted/blob - src/modules/core/transition_composite.c

   1 /*
   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>
   5  *
   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.
  10  *
  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.
  15  *
  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.
  19  */
  20
  21 #include "transition_composite.h"
  22 #include <framework/mlt_frame.h>
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <ctype.h>
  27 #include <string.h>
  28 #include <math.h>
  29
  30 /** Geometry struct.
  31 */
  32
  33 struct geometry_s
  34 {
  35         float position;
  36         float mix;
  37         int nw; // normalised width
  38         int nh; // normalised height
  39         int sw; // scaled width, not including consumer scale based upon w/nw
  40         int sh; // scaled height, not including consumer scale based upon h/nh
  41         float x;
  42         float y;
  43         float w;
  44         float h;
  45         int halign; // horizontal alignment: 0=left, 1=center, 2=right
  46         int valign; // vertical alignment: 0=top, 1=middle, 2=bottom
  47         int distort;
  48         struct geometry_s *next;
  49 };
  50
  51 /** Parse a value from a geometry string.
  52 */
  53
  54 static float parse_value( char **ptr, int normalisation, char delim, float defaults )
  55 {
  56         float value = defaults;
  57
  58         if ( *ptr != NULL && **ptr != '\0' )
  59         {
  60                 char *end = NULL;
  61                 value = strtod( *ptr, &end );
  62                 if ( end != NULL )
  63                 {
  64                         if ( *end == '%' )
  65                                 value = ( value / 100.0 ) * normalisation;
  66                         while ( *end == delim || *end == '%' )
  67                                 end ++;
  68                 }
  69                 *ptr = end;
  70         }
  71
  72         return value;
  73 }
  74
  75 /** Parse a geometry property string with the syntax X,Y:WxH:MIX. Any value can be
  76         expressed as a percentage by appending a % after the value, otherwise values are
  77         assumed to be relative to the normalised dimensions of the consumer.
  78 */
  79
  80 static void geometry_parse( struct geometry_s *geometry, struct geometry_s *defaults, char *property, int nw, int nh )
  81 {
  82         // Assign normalised width and height
  83         geometry->nw = nw;
  84         geometry->nh = nh;
  85
  86         // Assign from defaults if available
  87         if ( defaults != NULL )
  88         {
  89                 geometry->x = defaults->x;
  90                 geometry->y = defaults->y;
  91                 geometry->w = geometry->sw = defaults->w;
  92                 geometry->h = geometry->sh = defaults->h;
  93                 geometry->distort = defaults->distort;
  94                 geometry->mix = defaults->mix;
  95                 defaults->next = geometry;
  96         }
  97         else
  98         {
  99                 geometry->mix = 100;
 100         }
 101
 102         // Parse the geomtry string
 103         if ( property != NULL && strcmp( property, "" ) )
 104         {
 105                 char *ptr = property;
 106                 geometry->x = parse_value( &ptr, nw, ',', geometry->x );
 107                 geometry->y = parse_value( &ptr, nh, ':', geometry->y );
 108                 geometry->w = geometry->sw = parse_value( &ptr, nw, 'x', geometry->w );
 109                 geometry->h = geometry->sh = parse_value( &ptr, nh, ':', geometry->h );
 110                 if ( *ptr == '!' )
 111                 {
 112                         geometry->distort = 1;
 113                         ptr ++;
 114                         if ( *ptr == ':' )
 115                                 ptr ++;
 116                 }
 117                 geometry->mix = parse_value( &ptr, 100, ' ', geometry->mix );
 118         }
 119 }
 120
 121 /** Calculate real geometry.
 122 */
 123
 124 static void geometry_calculate( struct geometry_s *output, struct geometry_s *in, float position )
 125 {
 126         // Search in for position
 127         struct geometry_s *out = in->next;
 128
 129         if ( position >= 1.0 )
 130         {
 131                 int section = floor( position );
 132                 position -= section;
 133                 if ( section % 2 == 1 )
 134                         position = 1.0 - position;
 135         }
 136
 137         while ( out->next != NULL )
 138         {
 139                 if ( position >= in->position && position < out->position )
 140                         break;
 141
 142                 in = out;
 143                 out = in->next;
 144         }
 145
 146         position = ( position - in->position ) / ( out->position - in->position );
 147
 148         // Calculate this frames geometry
 149         output->nw = in->nw;
 150         output->nh = in->nh;
 151         output->x = in->x + ( out->x - in->x ) * position;
 152         output->y = in->y + ( out->y - in->y ) * position;
 153         output->w = in->w + ( out->w - in->w ) * position;
 154         output->h = in->h + ( out->h - in->h ) * position;
 155         output->sw = output->w;
 156         output->sh = output->h;
 157         output->mix = in->mix + ( out->mix - in->mix ) * position;
 158         output->distort = in->distort;
 159
 160         output->x = ( int )floor( output->x ) & 0xfffffffe;
 161         output->w = ( int )floor( output->w ) & 0xfffffffe;
 162         output->sw &= 0xfffffffe;
 163 }
 164
 165 void transition_destroy_keys( void *arg )
 166 {
 167         struct geometry_s *ptr = arg;
 168         struct geometry_s *next = NULL;
 169
 170         while ( ptr != NULL )
 171         {
 172                 next = ptr->next;
 173                 free( ptr );
 174                 ptr = next;
 175         }
 176 }
 177
 178 static struct geometry_s *transition_parse_keys( mlt_transition this,  int normalised_width, int normalised_height )
 179 {
 180         // Loop variable for property interrogation
 181         int i = 0;
 182
 183         // Get the properties of the transition
 184         mlt_properties properties = mlt_transition_properties( this );
 185
 186         // Get the in and out position
 187         mlt_position in = mlt_transition_get_in( this );
 188         mlt_position out = mlt_transition_get_out( this );
 189
 190         // Create the start
 191         struct geometry_s *start = calloc( 1, sizeof( struct geometry_s ) );
 192
 193         // Create the end (we always need two entries)
 194         struct geometry_s *end = calloc( 1, sizeof( struct geometry_s ) );
 195
 196         // Pointer
 197         struct geometry_s *ptr = start;
 198
 199         // Parse the start property
 200         geometry_parse( start, NULL, mlt_properties_get( properties, "start" ), normalised_width, normalised_height );
 201
 202         // Parse the keys in between
 203         for ( i = 0; i < mlt_properties_count( properties ); i ++ )
 204         {
 205                 // Get the name of the property
 206                 char *name = mlt_properties_get_name( properties, i );
 207
 208                 // Check that it's valid
 209                 if ( !strncmp( name, "key[", 4 ) )
 210                 {
 211                         // Get the value of the property
 212                         char *value = mlt_properties_get_value( properties, i );
 213
 214                         // Determine the frame number
 215                         int frame = atoi( name + 4 );
 216
 217                         // Determine the position
 218                         float position = 0;
 219
 220                         if ( frame >= 0 && frame < ( out - in ) )
 221                                 position = ( float )frame / ( float )( out - in + 1 );
 222                         else if ( frame < 0 && - frame < ( out - in ) )
 223                                 position = ( float )( out - in + frame ) / ( float )( out - in + 1 );
 224
 225                         // For now, we'll exclude all keys received out of order
 226                         if ( position > ptr->position )
 227                         {
 228                                 // Create a new geometry
 229                                 struct geometry_s *temp = calloc( 1, sizeof( struct geometry_s ) );
 230
 231                                 // Parse and add to the list
 232                                 geometry_parse( temp, ptr, value, normalised_width, normalised_height );
 233
 234                                 // Assign the position
 235                                 temp->position = position;
 236
 237                                 // Allow the next to be appended after this one
 238                                 ptr = temp;
 239                         }
 240                         else
 241                         {
 242                                 fprintf( stderr, "Key out of order - skipping %s\n", name );
 243                         }
 244                 }
 245         }
 246
 247         // Parse the end
 248         geometry_parse( end, ptr, mlt_properties_get( properties, "end" ), normalised_width, normalised_height );
 249         if ( out > 0 )
 250                 end->position = ( float )( out - in ) / ( float )( out - in + 1 );
 251         else
 252                 end->position = 1;
 253
 254         // Assign to properties to ensure we get destroyed
 255         mlt_properties_set_data( properties, "geometries", start, 0, transition_destroy_keys, NULL );
 256
 257         return start;
 258 }
 259
 260 /** Parse the alignment properties into the geometry.
 261 */
 262
 263 static int alignment_parse( char* align )
 264 {
 265         int ret = 0;
 266
 267         if ( align == NULL );
 268         else if ( isdigit( align[ 0 ] ) )
 269                 ret = atoi( align );
 270         else if ( align[ 0 ] == 'c' || align[ 0 ] == 'm' )
 271                 ret = 1;
 272         else if ( align[ 0 ] == 'r' || align[ 0 ] == 'b' )
 273                 ret = 2;
 274
 275         return ret;
 276 }
 277
 278 /** Adjust position according to scaled size and alignment properties.
 279 */
 280
 281 static void alignment_calculate( struct geometry_s *geometry )
 282 {
 283         geometry->x += ( geometry->w - geometry->sw ) * geometry->halign / 2;
 284         geometry->y += ( geometry->h - geometry->sh ) * geometry->valign / 2;
 285 }
 286
 287 /** Calculate the position for this frame.
 288 */
 289
 290 static float position_calculate( mlt_transition this, mlt_frame frame )
 291 {
 292         // Get the in and out position
 293         mlt_position in = mlt_transition_get_in( this );
 294         mlt_position out = mlt_transition_get_out( this );
 295
 296         // Get the position
 297         mlt_position position = mlt_frame_get_position( frame );
 298
 299         // Now do the calcs
 300         return ( float )( position - in ) / ( float )( out - in + 1 );
 301 }
 302
 303 /** Calculate the field delta for this frame - position between two frames.
 304 */
 305
 306 static inline float delta_calculate( mlt_transition this, mlt_frame frame )
 307 {
 308         // Get the in and out position
 309         mlt_position in = mlt_transition_get_in( this );
 310         mlt_position out = mlt_transition_get_out( this );
 311
 312         // Get the position of the frame
 313         mlt_position position = mlt_frame_get_position( frame );
 314
 315         // Now do the calcs
 316         float x = ( float )( position - in ) / ( float )( out - in + 1 );
 317         float y = ( float )( position + 1 - in ) / ( float )( out - in + 1 );
 318
 319         return ( y - x ) / 2.0;
 320 }
 321
 322 static int get_value( mlt_properties properties, char *preferred, char *fallback )
 323 {
 324         int value = mlt_properties_get_int( properties, preferred );
 325         if ( value == 0 )
 326                 value = mlt_properties_get_int( properties, fallback );
 327         return value;
 328 }
 329
 330 /** Composite function.
 331 */
 332
 333 static int composite_yuv( uint8_t *p_dest, int width_dest, int height_dest, int bpp, uint8_t *p_src, int width_src, int height_src, uint8_t *p_alpha, struct geometry_s geometry, int field )
 334 {
 335         int ret = 0;
 336         int i, j;
 337         int x_src = 0, y_src = 0;
 338         int32_t weight = ( 1 << 16 ) * ( geometry.mix / 100 );
 339         int stride_src = width_src * bpp;
 340         int stride_dest = width_dest * bpp;
 341
 342         // Adjust to consumer scale
 343         int x = geometry.x * width_dest / geometry.nw;
 344         int y = geometry.y * height_dest / geometry.nh;
 345
 346         x &= 0xfffffffe;
 347         width_src &= 0xfffffffe;
 348
 349         // optimization points - no work to do
 350         if ( width_src <= 0 || height_src <= 0 )
 351                 return ret;
 352
 353         if ( ( x < 0 && -x >= width_src ) || ( y < 0 && -y >= height_src ) )
 354                 return ret;
 355
 356         // crop overlay off the left edge of frame
 357         if ( x < 0 )
 358         {
 359                 x_src = -x;
 360                 width_src -= x_src;
 361                 x = 0;
 362         }
 363
 364         // crop overlay beyond right edge of frame
 365         else if ( x + width_src > width_dest )
 366                 width_src = width_dest - x;
 367
 368         // crop overlay off the top edge of the frame
 369         if ( y < 0 )
 370         {
 371                 y_src = -y;
 372                 height_src -= y_src;
 373         }
 374         // crop overlay below bottom edge of frame
 375         else if ( y + height_src > height_dest )
 376                 height_src = height_dest - y;
 377
 378         // offset pointer into overlay buffer based on cropping
 379         p_src += x_src * bpp + y_src * stride_src;
 380
 381         // offset pointer into frame buffer based upon positive coordinates only!
 382         p_dest += ( x < 0 ? 0 : x ) * bpp + ( y < 0 ? 0 : y ) * stride_dest;
 383
 384         // offset pointer into alpha channel based upon cropping
 385         if ( p_alpha )
 386                 p_alpha += x_src + y_src * stride_src / bpp;
 387
 388         // Assuming lower field first
 389         // Special care is taken to make sure the b_frame is aligned to the correct field.
 390         // field 0 = lower field and y should be odd (y is 0-based).
 391         // field 1 = upper field and y should be even.
 392         if ( ( field > -1 ) && ( y % 2 == field ) )
 393         {
 394                 //fprintf( stderr, "field %d y %d\n", field, y );
 395                 if ( ( field == 1 && y < height_dest - 1 ) || ( field == 0 && y == 0 ) )
 396                         p_dest += stride_dest;
 397                 else
 398                         p_dest -= stride_dest;
 399         }
 400
 401         // On the second field, use the other lines from b_frame
 402         if ( field == 1 )
 403         {
 404                 p_src += stride_src;
 405                 if ( p_alpha )
 406                         p_alpha += stride_src / bpp;
 407                 height_src--;
 408         }
 409
 410         uint8_t *p = p_src;
 411         uint8_t *q = p_dest;
 412         uint8_t *o = p_dest;
 413         uint8_t *z = p_alpha;
 414
 415         uint8_t a;
 416         int32_t value;
 417         int step = ( field > -1 ) ? 2 : 1;
 418
 419         stride_src = stride_src * step;
 420         int alpha_stride = stride_src / bpp;
 421         stride_dest = stride_dest * step;
 422
 423         // now do the compositing only to cropped extents
 424         for ( i = 0; i < height_src; i += step )
 425         {
 426                 p = p_src;
 427                 q = p_dest;
 428                 o = q;
 429                 z = p_alpha;
 430
 431                 for ( j = 0; j < width_src; j ++ )
 432                 {
 433                         a = ( z == NULL ) ? 255 : *z ++;
 434                         value = ( weight * ( a + 1 ) ) >> 8;
 435                         *o ++ = ( *p++ * value + *q++ * ( ( 1 << 16 ) - value ) ) >> 16;
 436                         *o ++ = ( *p++ * value + *q++ * ( ( 1 << 16 ) - value ) ) >> 16;
 437                 }
 438
 439                 p_src += stride_src;
 440                 p_dest += stride_dest;
 441                 if ( p_alpha )
 442                         p_alpha += alpha_stride;
 443         }
 444
 445         return ret;
 446 }
 447
 448
 449 /** Get the properly sized image from b_frame.
 450 */
 451
 452 static int get_b_frame_image( mlt_transition this, mlt_frame b_frame, uint8_t **image, int *width, int *height, struct geometry_s *geometry )
 453 {
 454         int ret = 0;
 455         mlt_image_format format = mlt_image_yuv422;
 456
 457         // Get the properties objects
 458         mlt_properties b_props = mlt_frame_properties( b_frame );
 459         mlt_properties properties = mlt_transition_properties( this );
 460
 461         if ( mlt_properties_get( properties, "distort" ) == NULL && geometry->distort == 0 )
 462         {
 463                 // Adjust b_frame pixel aspect
 464                 int normalised_width = geometry->w;
 465                 int normalised_height = geometry->h;
 466                 int real_width = get_value( b_props, "real_width", "width" );
 467                 int real_height = get_value( b_props, "real_height", "height" );
 468                 double input_ar = mlt_frame_get_aspect_ratio( b_frame );
 469                 double output_ar = mlt_properties_get_double( b_props, "consumer_aspect_ratio" );
 470                 int scaled_width = real_width;
 471                 int scaled_height = real_height;
 472                 double output_sar = ( double ) geometry->nw / geometry->nh / output_ar;
 473
 474                 // If the output is fat pixels (NTSC) then stretch our input horizontally
 475                 // derived from: output_sar / input_sar * real_width
 476                 scaled_width = output_sar * real_height * input_ar;
 477
 478                 // Now ensure that our images fit in the normalised frame
 479                 if ( scaled_width > normalised_width )
 480                 {
 481                         scaled_height = scaled_height * normalised_width / scaled_width;
 482                         scaled_width = normalised_width;
 483                 }
 484                 if ( scaled_height > normalised_height )
 485                 {
 486                         scaled_width = scaled_width * normalised_height / scaled_height;
 487                         scaled_height = normalised_height;
 488                 }
 489
 490                 // Now apply the fill
 491                 // TODO: Should combine fill/distort in one property
 492                 if ( mlt_properties_get( properties, "fill" ) != NULL )
 493                 {
 494                         scaled_width = ( geometry->w / scaled_width ) * scaled_width;
 495                         scaled_height = ( geometry->h / scaled_height ) * scaled_height;
 496                 }
 497
 498                 // Save the new scaled dimensions
 499                 geometry->sw = scaled_width;
 500                 geometry->sh = scaled_height;
 501         }
 502
 503         // We want to ensure that we bypass resize now...
 504         mlt_properties_set( b_props, "distort", "true" );
 505
 506         // Take into consideration alignment for optimisation
 507         alignment_calculate( geometry );
 508
 509         // Adjust to consumer scale
 510         int x = geometry->x * *width / geometry->nw;
 511         int y = geometry->y * *height / geometry->nh;
 512         *width = geometry->sw * *width / geometry->nw;
 513         *height = geometry->sh * *height / geometry->nh;
 514
 515         x -= x % 2;
 516
 517         // optimization points - no work to do
 518         if ( *width <= 0 || *height <= 0 )
 519                 return 1;
 520
 521         if ( ( x < 0 && -x >= *width ) || ( y < 0 && -y >= *height ) )
 522                 return 1;
 523
 524         ret = mlt_frame_get_image( b_frame, image, &format, width, height, 1 );
 525
 526         return ret;
 527 }
 528
 529
 530 static uint8_t *transition_get_alpha_mask( mlt_frame this )
 531 {
 532         // Obtain properties of frame
 533         mlt_properties properties = mlt_frame_properties( this );
 534
 535         // Return the alpha mask
 536         return mlt_properties_get_data( properties, "alpha", NULL );
 537 }
 538
 539 struct geometry_s *composite_calculate( struct geometry_s *result, mlt_transition this, mlt_frame a_frame, float position )
 540 {
 541         // Get the properties from the transition
 542         mlt_properties properties = mlt_transition_properties( this );
 543
 544         // Get the properties from the frame
 545         mlt_properties a_props = mlt_frame_properties( a_frame );
 546
 547         // Structures for geometry
 548         struct geometry_s *start = mlt_properties_get_data( properties, "geometries", NULL );
 549
 550         // Now parse the geometries
 551         if ( start == NULL )
 552         {
 553                 // Obtain the normalised width and height from the a_frame
 554                 int normalised_width = mlt_properties_get_int( a_props, "normalised_width" );
 555                 int normalised_height = mlt_properties_get_int( a_props, "normalised_height" );
 556
 557                 // Parse the transitions properties
 558                 start = transition_parse_keys( this, normalised_width, normalised_height );
 559         }
 560
 561         // Do the calculation
 562         geometry_calculate( result, start, position );
 563
 564         // Now parse the alignment
 565         result->halign = alignment_parse( mlt_properties_get( properties, "halign" ) );
 566         result->valign = alignment_parse( mlt_properties_get( properties, "valign" ) );
 567
 568         return start;
 569 }
 570
 571 mlt_frame composite_copy_region( mlt_transition this, mlt_frame a_frame )
 572 {
 573         // Create a frame to return
 574         mlt_frame b_frame = mlt_frame_init( );
 575
 576         // Get the properties of the a frame
 577         mlt_properties a_props = mlt_frame_properties( a_frame );
 578
 579         // Get the properties of the b frame
 580         mlt_properties b_props = mlt_frame_properties( b_frame );
 581
 582         // Get the position
 583         float position = position_calculate( this, a_frame );
 584
 585         // Destination image
 586         uint8_t *dest = NULL;
 587
 588         // Get the image and dimensions
 589         uint8_t *image = mlt_properties_get_data( a_props, "image", NULL );
 590         int width = mlt_properties_get_int( a_props, "width" );
 591         int height = mlt_properties_get_int( a_props, "height" );
 592
 593         // Pointers for copy operation
 594         uint8_t *p;
 595         uint8_t *q;
 596         uint8_t *r;
 597
 598         // Corrdinates
 599         int w = 0;
 600         int h = 0;
 601         int x = 0;
 602         int y = 0;
 603
 604         // Will need to know region to copy
 605         struct geometry_s result;
 606
 607         // Calculate the region now
 608         composite_calculate( &result, this, a_frame, position );
 609
 610         // Need to scale down to actual dimensions
 611         x = result.x * width / result.nw ;
 612         y = result.y * height / result.nh;
 613         w = result.sw * width / result.nw;
 614         h = result.sh * height / result.nh;
 615
 616         x &= 0xfffffffe;
 617         w &= 0xfffffffe;
 618
 619         // Now we need to create a new destination image
 620         dest = mlt_pool_alloc( w * h * 2 );
 621
 622         // Copy the region of the image
 623         p = image + y * width * 2 + x * 2;
 624         q = dest;
 625         r = dest + w * h * 2;
 626
 627         while ( q < r )
 628         {
 629                 memcpy( q, p, w * 2 );
 630                 q += w * 2;
 631                 p += width * 2;
 632         }
 633
 634         // Assign to the new frame
 635         mlt_properties_set_data( b_props, "image", dest, w * h * 2, mlt_pool_release, NULL );
 636         mlt_properties_set_int( b_props, "width", w );
 637         mlt_properties_set_int( b_props, "height", h );
 638
 639         // Return the frame
 640         return b_frame;
 641 }
 642
 643 /** Get the image.
 644 */
 645
 646 static int transition_get_image( mlt_frame a_frame, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
 647 {
 648         // Get the b frame from the stack
 649         mlt_frame b_frame = mlt_frame_pop_frame( a_frame );
 650
 651         // Get the transition from the a frame
 652         mlt_transition this = mlt_frame_pop_service( a_frame );
 653
 654         // This compositer is yuv422 only
 655         *format = mlt_image_yuv422;
 656
 657         // Get the image from the a frame
 658         mlt_frame_get_image( a_frame, image, format, width, height, 1 );
 659
 660         if ( b_frame != NULL )
 661         {
 662                 // Get the properties of the a frame
 663                 mlt_properties a_props = mlt_frame_properties( a_frame );
 664
 665                 // Get the properties of the b frame
 666                 mlt_properties b_props = mlt_frame_properties( b_frame );
 667
 668                 // Get the properties from the transition
 669                 mlt_properties properties = mlt_transition_properties( this );
 670
 671                 // Structures for geometry
 672                 struct geometry_s result;
 673
 674                 // Calculate the position
 675                 float position = mlt_properties_get_double( b_props, "relative_position" );
 676                 float delta = delta_calculate( this, a_frame );
 677
 678                 // Do the calculation
 679                 struct geometry_s *start = composite_calculate( &result, this, a_frame, position );
 680
 681                 // Since we are the consumer of the b_frame, we must pass along these
 682                 // consumer properties from the a_frame
 683                 mlt_properties_set_double( b_props, "consumer_aspect_ratio", mlt_properties_get_double( a_props, "consumer_aspect_ratio" ) );
 684                 mlt_properties_set_double( b_props, "consumer_scale", mlt_properties_get_double( a_props, "consumer_scale" ) );
 685
 686                 // Get the image from the b frame
 687                 uint8_t *image_b = NULL;
 688                 int width_b = *width;
 689                 int height_b = *height;
 690
 691                 if ( get_b_frame_image( this, b_frame, &image_b, &width_b, &height_b, &result ) == 0 )
 692                 {
 693                         uint8_t *dest = *image;
 694                         uint8_t *src = image_b;
 695                         int bpp = 2;
 696                         uint8_t *alpha = mlt_frame_get_alpha_mask( b_frame );
 697                         int progressive = mlt_properties_get_int( a_props, "progressive" ) ||
 698                                         mlt_properties_get_int( a_props, "consumer_progressive" ) ||
 699                                         mlt_properties_get_int( properties, "progressive" );
 700                         int field;
 701
 702                         for ( field = 0; field < ( progressive ? 1 : 2 ); field++ )
 703                         {
 704                                 // Assume lower field (0) first
 705                                 float field_position = position + field * delta;
 706
 707                                 // Do the calculation if we need to
 708                                 geometry_calculate( &result, start, field_position );
 709
 710                                 // Align
 711                                 alignment_calculate( &result );
 712
 713                                 // Composite the b_frame on the a_frame
 714                                 composite_yuv( dest, *width, *height, bpp, src, width_b, height_b, alpha, result, progressive ? -1 : field );
 715                         }
 716                 }
 717         }
 718
 719         return 0;
 720 }
 721
 722 /** Composition transition processing.
 723 */
 724
 725 static mlt_frame composite_process( mlt_transition this, mlt_frame a_frame, mlt_frame b_frame )
 726 {
 727         // Propogate the transition properties to the b frame
 728         mlt_properties_set_double( mlt_frame_properties( b_frame ), "relative_position", position_calculate( this, a_frame ) );
 729         mlt_frame_push_service( a_frame, this );
 730         mlt_frame_push_get_image( a_frame, transition_get_image );
 731         mlt_frame_push_frame( a_frame, b_frame );
 732         return a_frame;
 733 }
 734
 735 /** Constructor for the filter.
 736 */
 737
 738 mlt_transition transition_composite_init( char *arg )
 739 {
 740         mlt_transition this = calloc( sizeof( struct mlt_transition_s ), 1 );
 741         if ( this != NULL && mlt_transition_init( this, NULL ) == 0 )
 742         {
 743                 this->process = composite_process;
 744                 mlt_properties_set( mlt_transition_properties( this ), "start", arg != NULL ? arg : "85%,5%:10%x10%" );
 745         }
 746         return this;
 747 }
 748