research.m1stereo.tv/gitweb/ - melted/blob - mlt/src/framework/mlt_frame.c

   1 /*
   2  * mlt_frame.c -- interface for all frame classes
   3  * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
   4  * Author: Charles Yates <charles.yates@pandora.be>
   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 "config.h"
  22 #include "mlt_frame.h"
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27 typedef struct
  28 {
  29         mlt_image_format vfmt;
  30         int width;
  31         int height;
  32         uint8_t *image;
  33         uint8_t *alpha;
  34         mlt_audio_format afmt;
  35         int16_t *audio;
  36 }
  37 frame_test;
  38
  39 static frame_test test_card = { mlt_image_none, 0, 0, NULL, NULL, mlt_audio_none, NULL };
  40
  41 /** Constructor for a frame.
  42 */
  43
  44 mlt_frame mlt_frame_init( )
  45 {
  46         // Allocate a frame
  47         mlt_frame this = calloc( sizeof( struct mlt_frame_s ), 1 );
  48
  49         if ( this != NULL )
  50         {
  51                 // Initialise the properties
  52                 mlt_properties properties = &this->parent;
  53                 mlt_properties_init( properties, this );
  54
  55                 // Set default properties on the frame
  56                 mlt_properties_set_position( properties, "position", 0.0 );
  57                 mlt_properties_set_data( properties, "image", NULL, 0, NULL, NULL );
  58                 mlt_properties_set_int( properties, "width", 720 );
  59                 mlt_properties_set_int( properties, "height", 576 );
  60                 mlt_properties_set_double( properties, "aspect_ratio", 4.0 / 3.0 );
  61                 mlt_properties_set_data( properties, "audio", NULL, 0, NULL, NULL );
  62                 mlt_properties_set_data( properties, "alpha", NULL, 0, NULL, NULL );
  63         }
  64         return this;
  65 }
  66
  67 /** Fetch the frames properties.
  68 */
  69
  70 mlt_properties mlt_frame_properties( mlt_frame this )
  71 {
  72         return &this->parent;
  73 }
  74
  75 /** Check if we have a way to derive something other than a test card.
  76 */
  77
  78 int mlt_frame_is_test_card( mlt_frame this )
  79 {
  80         return this->stack_get_image_size == 0;
  81 }
  82
  83 /** Get the aspect ratio of the frame.
  84 */
  85
  86 double mlt_frame_get_aspect_ratio( mlt_frame this )
  87 {
  88         mlt_properties properties = mlt_frame_properties( this );
  89         return mlt_properties_get_double( properties, "aspect_ratio" );
  90 }
  91
  92 /** Set the aspect ratio of the frame.
  93 */
  94
  95 int mlt_frame_set_aspect_ratio( mlt_frame this, double value )
  96 {
  97         mlt_properties properties = mlt_frame_properties( this );
  98         return mlt_properties_set_double( properties, "aspect_ratio", value );
  99 }
 100
 101 /** Get the position of this frame.
 102 */
 103
 104 mlt_position mlt_frame_get_position( mlt_frame this )
 105 {
 106         mlt_properties properties = mlt_frame_properties( this );
 107         return mlt_properties_get_position( properties, "position" );
 108 }
 109
 110 /** Set the position of this frame.
 111 */
 112
 113 int mlt_frame_set_position( mlt_frame this, mlt_position value )
 114 {
 115         mlt_properties properties = mlt_frame_properties( this );
 116         return mlt_properties_set_position( properties, "position", value );
 117 }
 118
 119 /** Stack a get_image callback.
 120 */
 121
 122 int mlt_frame_push_get_image( mlt_frame this, mlt_get_image get_image )
 123 {
 124         int ret = this->stack_get_image_size >= 10;
 125         if ( ret == 0 )
 126                 this->stack_get_image[ this->stack_get_image_size ++ ] = get_image;
 127         return ret;
 128 }
 129
 130 /** Pop a get_image callback.
 131 */
 132
 133 mlt_get_image mlt_frame_pop_get_image( mlt_frame this )
 134 {
 135         mlt_get_image result = NULL;
 136         if ( this->stack_get_image_size > 0 )
 137                 result = this->stack_get_image[ -- this->stack_get_image_size ];
 138         return result;
 139 }
 140
 141 /** Push a frame.
 142 */
 143
 144 int mlt_frame_push_frame( mlt_frame this, mlt_frame that )
 145 {
 146         int ret = this->stack_frame_size >= 10;
 147         if ( ret == 0 )
 148                 this->stack_frame[ this->stack_frame_size ++ ] = that;
 149         return ret;
 150 }
 151
 152 /** Pop a frame.
 153 */
 154
 155 mlt_frame mlt_frame_pop_frame( mlt_frame this )
 156 {
 157         mlt_frame result = NULL;
 158         if ( this->stack_frame_size > 0 )
 159                 result = this->stack_frame[ -- this->stack_frame_size ];
 160         return result;
 161 }
 162
 163 int mlt_frame_get_image( mlt_frame this, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
 164 {
 165         mlt_properties properties = mlt_frame_properties( this );
 166         mlt_get_image get_image = mlt_frame_pop_get_image( this );
 167
 168         if ( get_image != NULL )
 169         {
 170                 return get_image( this, buffer, format, width, height, writable );
 171         }
 172         else if ( mlt_properties_get_data( properties, "image", NULL ) != NULL )
 173         {
 174                 *format = mlt_image_yuv422;
 175                 *buffer = mlt_properties_get_data( properties, "image", NULL );
 176                 *width = mlt_properties_get_int( properties, "width" );
 177                 *height = mlt_properties_get_int( properties, "height" );
 178         }
 179         else
 180         {
 181                 if ( test_card.vfmt != *format )
 182                 {
 183                         uint8_t *p;
 184                         uint8_t *q;
 185
 186                         test_card.vfmt = *format;
 187                         test_card.width = *width == 0 ? 720 : *width;
 188                         test_card.height = *height == 0 ? 576 : *height;
 189
 190                         switch( *format )
 191                         {
 192                                 case mlt_image_none:
 193                                         break;
 194                                 case mlt_image_rgb24:
 195                                         test_card.image = realloc( test_card.image, test_card.width * test_card.height * 3 );
 196                                         memset( test_card.image, 255, test_card.width * test_card.height * 3 );
 197                                         break;
 198                                 case mlt_image_rgb24a:
 199                                         test_card.image = realloc( test_card.image, test_card.width * test_card.height * 4 );
 200                                         memset( test_card.image, 255, test_card.width * test_card.height * 4 );
 201                                         break;
 202                                 case mlt_image_yuv422:
 203                                         test_card.image = realloc( test_card.image, test_card.width * test_card.height * 2 );
 204                                         p = test_card.image;
 205                                         q = test_card.image + test_card.width * test_card.height * 2;
 206                                         while ( p != q )
 207                                         {
 208                                                 *p ++ = 255;
 209                                                 *p ++ = 128;
 210                                         }
 211                                         break;
 212                                 case mlt_image_yuv420p:
 213                                         test_card.image = realloc( test_card.image, test_card.width * test_card.height * 3 / 2 );
 214                                         memset( test_card.image, 255, test_card.width * test_card.height * 3 / 2 );
 215                                         break;
 216                         }
 217                 }
 218
 219                 *width = test_card.width;
 220                 *height = test_card.height;
 221                 *buffer = test_card.image;
 222         }
 223
 224         return 0;
 225 }
 226
 227 uint8_t *mlt_frame_get_alpha_mask( mlt_frame this )
 228 {
 229         if ( this->get_alpha_mask != NULL )
 230                 return this->get_alpha_mask( this );
 231         return test_card.alpha;
 232 }
 233
 234 int mlt_frame_get_audio( mlt_frame this, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
 235 {
 236         if ( this->get_audio != NULL )
 237         {
 238                 return this->get_audio( this, buffer, format, frequency, channels, samples );
 239         }
 240         else
 241         {
 242                 if ( *samples <= 0 )
 243                         *samples = 1920;
 244                 if ( *channels <= 0 )
 245                         *channels = 2;
 246                 if ( *frequency <= 0 )
 247                         *frequency = 48000;
 248                 if ( test_card.audio == NULL || test_card.afmt != *format )
 249                 {
 250                         test_card.afmt = *format;
 251                         test_card.audio = realloc( test_card.audio, *samples * *channels * sizeof( int16_t ) );
 252                         memset( test_card.audio, 0, *samples * *channels * sizeof( int16_t ) );
 253                 }
 254
 255                 *buffer = test_card.audio;
 256         }
 257         return 0;
 258 }
 259
 260 void mlt_frame_close( mlt_frame this )
 261 {
 262         mlt_frame frame = mlt_frame_pop_frame( this );
 263
 264         while ( frame != NULL )
 265         {
 266                 mlt_frame_close( frame);
 267                 frame = mlt_frame_pop_frame( this );
 268         }
 269
 270         mlt_properties_close( &this->parent );
 271
 272         free( this );
 273 }
 274
 275 /***** convenience functions *****/
 276 #define RGB2YUV(r, g, b, y, u, v)\
 277   y = (306*r + 601*g + 117*b)  >> 10;\
 278   u = ((-172*r - 340*g + 512*b) >> 10)  + 128;\
 279   v = ((512*r - 429*g - 83*b) >> 10) + 128;\
 280   y = y < 0 ? 0 : y;\
 281   u = u < 0 ? 0 : u;\
 282   v = v < 0 ? 0 : v;\
 283   y = y > 255 ? 255 : y;\
 284   u = u > 255 ? 255 : u;\
 285   v = v > 255 ? 255 : v
 286
 287 int mlt_convert_rgb24a_to_yuv422( uint8_t *rgba, int width, int height, int stride, uint8_t *yuv, uint8_t *alpha )
 288 {
 289         int ret = 0;
 290         register int y0, y1, u0, u1, v0, v1;
 291         register int r, g, b;
 292         register uint8_t *d = yuv;
 293         register int i, j;
 294
 295         for ( i = 0; i < height; i++ )
 296         {
 297                 register uint8_t *s = rgba + ( stride * i );
 298                 for ( j = 0; j < ( width / 2 ); j++ )
 299                 {
 300                         r = *s++;
 301                         g = *s++;
 302                         b = *s++;
 303                         *alpha++ = *s++;
 304                         RGB2YUV (r, g, b, y0, u0 , v0);
 305                         r = *s++;
 306                         g = *s++;
 307                         b = *s++;
 308                         *alpha++ = *s++;
 309                         RGB2YUV (r, g, b, y1, u1 , v1);
 310                         *d++ = y0;
 311                         *d++ = (u0+u1) >> 1;
 312                         *d++ = y1;
 313                         *d++ = (v0+v1) >> 1;
 314                 }
 315                 if ( width % 2 )
 316                 {
 317                         r = *s++;
 318                         g = *s++;
 319                         b = *s++;
 320                         *alpha++ = *s++;
 321                         RGB2YUV (r, g, b, y0, u0 , v0);
 322                         *d++ = y0;
 323                         *d++ = u0;
 324                 }
 325         }
 326         return ret;
 327 }
 328
 329 int mlt_convert_rgb24_to_yuv422( uint8_t *rgb, int width, int height, int stride, uint8_t *yuv )
 330 {
 331         int ret = 0;
 332         register int y0, y1, u0, u1, v0, v1;
 333         register int r, g, b;
 334         register uint8_t *d = yuv;
 335         register int i, j;
 336
 337         for ( i = 0; i < height; i++ )
 338         {
 339                 register uint8_t *s = rgb + ( stride * i );
 340                 for ( j = 0; j < ( width / 2 ); j++ )
 341                 {
 342                         r = *s++;
 343                         g = *s++;
 344                         b = *s++;
 345                         RGB2YUV (r, g, b, y0, u0 , v0);
 346                         r = *s++;
 347                         g = *s++;
 348                         b = *s++;
 349                         RGB2YUV (r, g, b, y1, u1 , v1);
 350                         *d++ = y0;
 351                         *d++ = (u0+u1) >> 1;
 352                         *d++ = y1;
 353                         *d++ = (v0+v1) >> 1;
 354                 }
 355                 if ( width % 2 )
 356                 {
 357                         r = *s++;
 358                         g = *s++;
 359                         b = *s++;
 360                         RGB2YUV (r, g, b, y0, u0 , v0);
 361                         *d++ = y0;
 362                         *d++ = u0;
 363                 }
 364         }
 365         return ret;
 366 }
 367
 368 int mlt_convert_yuv420p_to_yuv422( uint8_t *yuv420p, int width, int height, int stride, uint8_t *yuv )
 369 {
 370         int ret = 0;
 371         register int i, j;
 372
 373         int half = width >> 1;
 374
 375         uint8_t *Y = yuv420p;
 376         uint8_t *U = Y + width * height;
 377         uint8_t *V = U + width * height / 4;
 378
 379         register uint8_t *d = yuv;
 380
 381         for ( i = 0; i < height; i++ )
 382         {
 383                 register uint8_t *u = U + ( i / 2 ) * ( half );
 384                 register uint8_t *v = V + ( i / 2 ) * ( half );
 385
 386                 for ( j = 0; j < half; j++ )
 387                 {
 388                         *d ++ = *Y ++;
 389                         *d ++ = *u ++;
 390                         *d ++ = *Y ++;
 391                         *d ++ = *v ++;
 392                 }
 393         }
 394         return ret;
 395 }
 396
 397 int mlt_frame_composite_yuv( mlt_frame this, mlt_frame that, int x, int y, float weight )
 398 {
 399         int ret = 0;
 400         int width_src = 0, height_src = 0;
 401         int width_dest = 0, height_dest = 0;
 402         mlt_image_format format_src = mlt_image_yuv422, format_dest = mlt_image_yuv422;
 403         uint8_t *p_src, *p_dest;
 404         int i, j;
 405         int stride_src;
 406         int stride_dest;
 407         int x_src = 0, y_src = 0;
 408
 409         // optimization point - no work to do
 410         if ( ( x < 0 && -x >= width_src ) || ( y < 0 && -y >= height_src ) )
 411                 return ret;
 412
 413         format_src = mlt_image_yuv422;
 414         format_dest = mlt_image_yuv422;
 415
 416         //fprintf( stderr, "call get_image on frame a\n"), fflush( stderr );
 417         mlt_frame_get_image( this, &p_dest, &format_dest, &width_dest, &height_dest, 1 /* writable */ );
 418         //fprintf( stderr, "call get_image on frame b\n"), fflush( stderr );
 419         mlt_frame_get_image( that, &p_src, &format_src, &width_src, &height_src, 0 /* writable */ );
 420
 421         //fprintf( stderr, "mlt_frame_composite_yuv %dx%d -> %dx%d\n", width_src, height_src, width_dest, height_dest );
 422         //fflush(stderr);
 423         //return ret;
 424         stride_src = width_src * 2;
 425         stride_dest = width_dest * 2;
 426
 427         // crop overlay off the left edge of frame
 428         if ( x < 0 )
 429         {
 430                 x_src = -x;
 431                 width_src -= x_src;
 432                 x = 0;
 433         }
 434
 435         // crop overlay beyond right edge of frame
 436         else if ( x + width_src > width_dest )
 437                 width_src = width_dest - x;
 438
 439         // crop overlay off the top edge of the frame
 440         if ( y < 0 )
 441         {
 442                 y_src = -y;
 443                 height_src -= y_src;
 444         }
 445         // crop overlay below bottom edge of frame
 446         else if ( y + height_src > height_dest )
 447                 height_src = height_dest - y;
 448
 449         // offset pointer into overlay buffer based on cropping
 450         p_src += x_src * 2 + y_src * stride_src;
 451
 452         // offset pointer into frame buffer based upon positive, even coordinates only!
 453 //      if ( interlaced && y % 2 )
 454 //              ++y;
 455         p_dest += ( x < 0 ? 0 : x ) * 2 + ( y < 0 ? 0 : y ) * stride_dest;
 456
 457         // Get the alpha channel of the overlay
 458         uint8_t *p_alpha = mlt_frame_get_alpha_mask( that );
 459
 460         // offset pointer into alpha channel based upon cropping
 461         if ( p_alpha )
 462                 p_alpha += x_src + y_src * stride_src / 2;
 463
 464         // now do the compositing only to cropped extents
 465         for ( i = 0; i < height_src; i++ )
 466         {
 467                 uint8_t *p = p_src;
 468                 uint8_t *q = p_dest;
 469                 uint8_t *o = p_dest;
 470                 uint8_t *z = p_alpha;
 471
 472                 for ( j = 0; j < width_src; j ++ )
 473                 {
 474                                 uint8_t y = *p ++;
 475                                 uint8_t uv = *p ++;
 476                                 uint8_t a = ( z == NULL ) ? 255 : *z ++;
 477                                 float value = ( weight * ( float ) a / 255.0 );
 478                                 *o ++ = (uint8_t)( y * value + *q++ * ( 1 - value ) );
 479                                 *o ++ = (uint8_t)( uv * value + *q++ * ( 1 - value ) );
 480                 }
 481
 482                 p_src += stride_src;
 483                 p_dest += stride_dest;
 484                 if ( p_alpha )
 485                         p_alpha += stride_src / 2;
 486         }
 487
 488         return ret;
 489 }
 490
 491 void *memfill( void *dst, void *src, int l, int elements )
 492 {
 493         int i = 0;
 494         if ( l == 2 )
 495         {
 496                 uint8_t *p = dst;
 497                 uint8_t *src1 = src;
 498                 uint8_t *src2 = src + 1;
 499                 for ( i = 0; i < elements; i ++ )
 500                 {
 501                         *p ++ = *src1;
 502                         *p ++ = *src2;
 503                 }
 504                 dst = p;
 505         }
 506         else
 507         {
 508                 for ( i = 0; i < elements; i ++ )
 509                         dst = memcpy( dst, src, l ) + l;
 510         }
 511         return dst;
 512 }
 513
 514 void mlt_resize_yuv422( uint8_t *output, int owidth, int oheight, uint8_t *input, int iwidth, int iheight )
 515 {
 516         // Calculate strides
 517         int istride = iwidth * 2;
 518         int ostride = owidth * 2;
 519
 520         iwidth = iwidth - ( iwidth % 4 );
 521         owidth = owidth - ( owidth % 4 );
 522         iheight = iheight - ( iheight % 2 );
 523         oheight = oheight - ( oheight % 2 );
 524
 525         // Coordinates (0,0 is middle of output)
 526         int y;
 527
 528         // Calculate ranges
 529         int out_x_range = owidth / 2;
 530         int out_y_range = oheight / 2;
 531         int in_x_range = iwidth / 2 < out_x_range ? iwidth / 2 : out_x_range;
 532         int in_y_range = iheight / 2 < out_y_range ? iheight / 2 : out_y_range;
 533
 534         // Output pointers
 535         uint8_t *out_line = output;
 536         uint8_t *out_ptr = out_line;
 537
 538         // Calculate a middle and possibly invalid pointer in the input
 539         uint8_t *in_middle = input + istride * ( iheight / 2 ) + ( iwidth / 2 ) * 2;
 540         int in_line = - in_y_range * istride - in_x_range * 2;
 541
 542         uint8_t black[ 2 ] = { 16, 128 };
 543
 544         // Loop for the entirety of our output height.
 545         for ( y = - out_y_range; y < out_y_range ; y ++ )
 546         {
 547         // Start at the beginning of the line
 548         out_ptr = out_line;
 549
 550                 if ( abs( y ) < iheight / 2 )
 551                 {
 552                         // Fill the outer part with black
 553                         out_ptr = memfill( out_ptr, black, 2, out_x_range - in_x_range );
 554
 555                 // We're in the input range for this row.
 556                         memcpy( out_ptr, in_middle + in_line, 2 * iwidth );
 557                         out_ptr += 2 * iwidth;
 558
 559                         // Fill the outer part with black
 560                         out_ptr = memfill( out_ptr, black, 2, out_x_range - in_x_range );
 561
 562                 // Move to next input line
 563                 in_line += istride;
 564                 }
 565                 else
 566                 {
 567                         // Fill whole line with black
 568                         out_ptr = memfill( out_ptr, black, 2, owidth );
 569                 }
 570
 571         // Move to next output line
 572         out_line += ostride;
 573         }
 574 }
 575
 576 /** A resizing function for yuv422 frames - this does not rescale, but simply
 577         resizes. It assumes yuv422 images available on the frame so use with care.
 578 */
 579
 580 uint8_t *mlt_frame_resize_yuv422( mlt_frame this, int owidth, int oheight )
 581 {
 582         // Get properties
 583         mlt_properties properties = mlt_frame_properties( this );
 584
 585         // Get the input image, width and height
 586         uint8_t *input = mlt_properties_get_data( properties, "image", NULL );
 587         int iwidth = mlt_properties_get_int( properties, "width" );
 588         int iheight = mlt_properties_get_int( properties, "height" );
 589
 590         // If width and height are correct, don't do anything
 591         if ( iwidth != owidth || iheight != oheight )
 592         {
 593                 // Create the output image
 594                 uint8_t *output = malloc( owidth * oheight * 2 );
 595
 596                 // Call the generic resize
 597                 mlt_resize_yuv422( output, owidth, oheight, input, iwidth, iheight );
 598
 599                 // Now update the frame
 600                 mlt_properties_set_data( properties, "image", output, owidth * oheight * 2, free, NULL );
 601                 mlt_properties_set_int( properties, "width", owidth );
 602                 mlt_properties_set_int( properties, "height", oheight );
 603
 604                 // Return the output
 605                 return output;
 606         }
 607
 608         // No change, return input
 609         return input;
 610 }
 611
 612 /** A rescaling function for yuv422 frames - low quality, and provided for testing
 613         only. It assumes yuv422 images available on the frame so use with care.
 614 */
 615
 616 uint8_t *mlt_frame_rescale_yuv422( mlt_frame this, int owidth, int oheight )
 617 {
 618         // Get properties
 619         mlt_properties properties = mlt_frame_properties( this );
 620
 621         // Get the input image, width and height
 622         uint8_t *input = mlt_properties_get_data( properties, "image", NULL );
 623         int iwidth = mlt_properties_get_int( properties, "width" );
 624         int iheight = mlt_properties_get_int( properties, "height" );
 625
 626         // If width and height are correct, don't do anything
 627         if ( iwidth != owidth || iheight != oheight )
 628         {
 629                 // Create the output image
 630                 uint8_t *output = malloc( owidth * oheight * 2 );
 631
 632                 // Calculate strides
 633                 int istride = iwidth * 2;
 634                 int ostride = owidth * 2;
 635
 636                 iwidth = iwidth - ( iwidth % 4 );
 637
 638         // Coordinates (0,0 is middle of output)
 639         int y, x;
 640
 641                 // Derived coordinates
 642                 int dy, dx;
 643
 644         // Calculate ranges
 645         int out_x_range = owidth / 2;
 646         int out_y_range = oheight / 2;
 647         int in_x_range = iwidth / 2;
 648         int in_y_range = iheight / 2;
 649
 650         // Output pointers
 651         uint8_t *out_line = output;
 652         uint8_t *out_ptr;
 653
 654         // Calculate a middle pointer
 655         uint8_t *in_middle = input + istride * in_y_range + in_x_range * 2;
 656         uint8_t *in_line;
 657                 uint8_t *in_ptr;
 658
 659                 // Generate the affine transform scaling values
 660                 float scale_width = ( float )iwidth / ( float )owidth;
 661                 float scale_height = ( float )iheight / ( float )oheight;
 662
 663         // Loop for the entirety of our output height.
 664         for ( y = - out_y_range; y < out_y_range ; y ++ )
 665         {
 666                         // Calculate the derived y value
 667                         dy = scale_height * y;
 668
 669                 // Start at the beginning of the line
 670                 out_ptr = out_line;
 671
 672                 // Pointer to the middle of the input line
 673                 in_line = in_middle + dy * istride;
 674
 675                 // Loop for the entirety of our output row.
 676                 for ( x = - out_x_range; x < out_x_range; x += 1 )
 677                 {
 678                                 // Calculated the derived x
 679                                 dx = scale_width * x;
 680
 681                 // Check if x and y are in the valid input range.
 682                 if ( abs( dx ) < in_x_range && abs( dy ) < in_y_range  )
 683                 {
 684                         // We're in the input range for this row.
 685                                         in_ptr = in_line + ( dx >> 1 ) * 4 + 2 * ( x & 1 );
 686                         *out_ptr ++ = *in_ptr ++;
 687                         *out_ptr ++ = *in_ptr ++;
 688                 }
 689                 else
 690                 {
 691                         // We're not in the input range for this row.
 692                         *out_ptr ++ = 16;
 693                         *out_ptr ++ = 128;
 694                 }
 695                 }
 696
 697                 // Move to next output line
 698                 out_line += ostride;
 699         }
 700
 701                 // Now update the frame
 702                 mlt_properties_set_data( properties, "image", output, owidth * oheight * 2, free, NULL );
 703                 mlt_properties_set_int( properties, "width", owidth );
 704                 mlt_properties_set_int( properties, "height", oheight );
 705
 706                 // Return the output
 707                 return output;
 708         }
 709
 710         // No change, return input
 711         return input;
 712 }
 713
 714 int mlt_frame_mix_audio( mlt_frame this, mlt_frame that, float weight, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
 715 {
 716         int ret = 0;
 717         int16_t *p_src, *p_dest;
 718         int16_t *src, *dest;
 719         //static int16_t *extra_src = NULL, *extra_dest = NULL;
 720         static int extra_src_samples = 0, extra_dest_samples = 0;
 721         int frequency_src = 0, frequency_dest = 0;
 722         int channels_src = 0, channels_dest = 0;
 723         int samples_src = 0, samples_dest = 0;
 724         int i, j;
 725
 726         mlt_frame_get_audio( this, &p_dest, format, &frequency_dest, &channels_dest, &samples_dest );
 727         //fprintf( stderr, "frame dest samples %d channels %d position %f\n", samples_dest, channels_dest, mlt_properties_get_position( mlt_frame_properties( this ), "position" ) );
 728         mlt_frame_get_audio( that, &p_src, format, &frequency_src, &channels_src, &samples_src );
 729         //fprintf( stderr, "frame src  samples %d channels %d\n", samples_src, channels_src );
 730         if ( channels_src > 6 )
 731                 channels_src = 0;
 732         if ( channels_dest > 6 )
 733                 channels_dest = 0;
 734         if ( samples_src > 4000 )
 735                 samples_src = 0;
 736         if ( samples_dest > 4000 )
 737                 samples_dest = 0;
 738
 739 #if 0
 740         // Append new samples to leftovers
 741         if ( extra_dest_samples > 0 )
 742         {
 743                 fprintf( stderr, "prepending %d samples to dest\n", extra_dest_samples );
 744                 dest = realloc( extra_dest, ( samples_dest + extra_dest_samples ) * 2 * channels_dest );
 745                 memcpy( &extra_dest[ extra_dest_samples * channels_dest ], p_dest, samples_dest * 2 * channels_dest );
 746         }
 747         else
 748                 dest = p_dest;
 749         if ( extra_src_samples > 0 )
 750         {
 751                 fprintf( stderr, "prepending %d samples to src\n", extra_src_samples );
 752                 src = realloc( extra_src, ( samples_src + extra_src_samples ) * 2 * channels_src );
 753                 memcpy( &extra_src[ extra_src_samples * channels_src ], p_src, samples_src * 2 * channels_src );
 754         }
 755         else
 756                 src = p_src;
 757 #else
 758         src = p_src;
 759         dest = p_dest;
 760 #endif
 761
 762         // determine number of samples to process
 763         if ( samples_src + extra_src_samples < samples_dest + extra_dest_samples )
 764                 *samples = samples_src + extra_src_samples;
 765         else if ( samples_dest + extra_dest_samples < samples_src + extra_src_samples )
 766                 *samples = samples_dest + extra_dest_samples;
 767
 768         *channels = channels_src < channels_dest ? channels_src : channels_dest;
 769         *buffer = p_dest;
 770
 771         // Mixdown
 772         for ( i = 0; i < *samples; i++ )
 773         {
 774                 for ( j = 0; j < *channels; j++ )
 775                 {
 776                         double d = (double) dest[ i * channels_dest + j ];
 777                         double s = (double) src[ i * channels_src + j ];
 778                         dest[ i * channels_dest + j ] = s * weight + d * ( 1.0 - weight );
 779                 }
 780         }
 781
 782         // We have to copy --sigh
 783         if ( dest != p_dest )
 784                 memcpy( p_dest, dest, *samples * 2 * *channels );
 785
 786 #if 0
 787         // Store the leftovers
 788         if ( samples_src + extra_src_samples < samples_dest + extra_dest_samples )
 789         {
 790                 extra_dest_samples = ( samples_dest + extra_dest_samples ) - ( samples_src + extra_src_samples );
 791                 size_t size = extra_dest_samples * 2 * channels_dest;
 792                 fprintf( stderr, "storing %d samples from dest\n", extra_dest_samples );
 793                 if ( extra_dest )
 794                         free( extra_dest );
 795                 extra_dest = malloc( size );
 796                 if ( extra_dest )
 797                         memcpy( extra_dest, &p_dest[ ( samples_dest - extra_dest_samples - 1 ) * channels_dest ], size );
 798                 else
 799                         extra_dest_samples = 0;
 800         }
 801         else if ( samples_dest + extra_dest_samples < samples_src + extra_src_samples )
 802         {
 803                 extra_src_samples = ( samples_src + extra_src_samples ) - ( samples_dest + extra_dest_samples );
 804                 size_t size = extra_src_samples * 2 * channels_src;
 805                 fprintf( stderr, "storing %d samples from src\n", extra_dest_samples );
 806                 if ( extra_src )
 807                         free( extra_src );
 808                 extra_src = malloc( size );
 809                 if ( extra_src )
 810                         memcpy( extra_src, &p_src[ ( samples_src - extra_src_samples - 1 ) * channels_src ], size );
 811                 else
 812                         extra_src_samples = 0;
 813         }
 814 #endif
 815
 816         return ret;
 817 }
 818
 819 int mlt_sample_calculator( float fps, int frequency, int64_t position )
 820 {
 821         int samples = 0;
 822
 823         if ( fps > 29 && fps <= 30 )
 824         {
 825                 samples = frequency / 30;
 826
 827                 switch ( frequency )
 828                 {
 829                         case 48000:
 830                                 if ( position % 5 != 0 )
 831                                         samples += 2;
 832                                 break;
 833                         case 44100:
 834                                 if ( position % 300 == 0 )
 835                                         samples = 1471;
 836                                 else if ( position % 30 == 0 )
 837                                         samples = 1470;
 838                                 else if ( position % 2 == 0 )
 839                                         samples = 1472;
 840                                 else
 841                                         samples = 1471;
 842                                 break;
 843                         case 32000:
 844                                 if ( position % 30 == 0 )
 845                                         samples = 1068;
 846                                 else if ( position % 29 == 0 )
 847                                         samples = 1067;
 848                                 else if ( position % 4 == 2 )
 849                                         samples = 1067;
 850                                 else
 851                                         samples = 1068;
 852                                 break;
 853                         default:
 854                                 samples = 0;
 855                 }
 856         }
 857         else if ( fps != 0 )
 858         {
 859                 samples = frequency / fps;
 860         }
 861
 862         return samples;
 863 }
 864