research.m1stereo.tv/gitweb/ - melted/blob - 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 && mlt_properties_get_data( mlt_frame_properties( this ), "image", NULL ) == NULL );
  81 }
  82
  83 /** Check if we have a way to derive something than test audio.
  84 */
  85
  86 int mlt_frame_is_test_audio( mlt_frame this )
  87 {
  88         return this->get_audio == NULL;
  89 }
  90
  91 /** Get the aspect ratio of the frame.
  92 */
  93
  94 double mlt_frame_get_aspect_ratio( mlt_frame this )
  95 {
  96         return mlt_properties_get_double( mlt_frame_properties( this ), "aspect_ratio" );
  97 }
  98
  99 /** Set the aspect ratio of the frame.
 100 */
 101
 102 int mlt_frame_set_aspect_ratio( mlt_frame this, double value )
 103 {
 104         return mlt_properties_set_double( mlt_frame_properties( this ), "aspect_ratio", value );
 105 }
 106
 107 /** Get the position of this frame.
 108 */
 109
 110 mlt_position mlt_frame_get_position( mlt_frame this )
 111 {
 112         return mlt_properties_get_position( mlt_frame_properties( this ), "_position" );
 113 }
 114
 115 /** Set the position of this frame.
 116 */
 117
 118 int mlt_frame_set_position( mlt_frame this, mlt_position value )
 119 {
 120         return mlt_properties_set_position( mlt_frame_properties( this ), "_position", value );
 121 }
 122
 123 /** Stack a get_image callback.
 124 */
 125
 126 int mlt_frame_push_get_image( mlt_frame this, mlt_get_image get_image )
 127 {
 128         int ret = this->stack_get_image_size >= 10;
 129         if ( ret == 0 )
 130                 this->stack_get_image[ this->stack_get_image_size ++ ] = get_image;
 131         return ret;
 132 }
 133
 134 /** Pop a get_image callback.
 135 */
 136
 137 mlt_get_image mlt_frame_pop_get_image( mlt_frame this )
 138 {
 139         mlt_get_image result = NULL;
 140         if ( this->stack_get_image_size > 0 )
 141                 result = this->stack_get_image[ -- this->stack_get_image_size ];
 142         return result;
 143 }
 144
 145 /** Push a frame.
 146 */
 147
 148 int mlt_frame_push_frame( mlt_frame this, mlt_frame that )
 149 {
 150         int ret = this->stack_frame_size >= 10;
 151         if ( ret == 0 )
 152                 this->stack_frame[ this->stack_frame_size ++ ] = that;
 153         return ret;
 154 }
 155
 156 /** Pop a frame.
 157 */
 158
 159 mlt_frame mlt_frame_pop_frame( mlt_frame this )
 160 {
 161         mlt_frame result = NULL;
 162         if ( this->stack_frame_size > 0 )
 163                 result = this->stack_frame[ -- this->stack_frame_size ];
 164         return result;
 165 }
 166
 167 int mlt_frame_get_image( mlt_frame this, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
 168 {
 169         mlt_properties properties = mlt_frame_properties( this );
 170         mlt_get_image get_image = mlt_frame_pop_get_image( this );
 171
 172         if ( get_image != NULL )
 173         {
 174                 return get_image( this, buffer, format, width, height, writable );
 175         }
 176         else if ( mlt_properties_get_data( properties, "image", NULL ) != NULL )
 177         {
 178                 *format = mlt_image_yuv422;
 179                 *buffer = mlt_properties_get_data( properties, "image", NULL );
 180                 *width = mlt_properties_get_int( properties, "width" );
 181                 *height = mlt_properties_get_int( properties, "height" );
 182         }
 183         else
 184         {
 185                 if ( test_card.vfmt != *format )
 186                 {
 187                         uint8_t *p;
 188                         uint8_t *q;
 189
 190                         test_card.vfmt = *format;
 191                         test_card.width = *width == 0 ? 720 : *width;
 192                         test_card.height = *height == 0 ? 576 : *height;
 193
 194                         switch( *format )
 195                         {
 196                                 case mlt_image_none:
 197                                         break;
 198                                 case mlt_image_rgb24:
 199                                         test_card.image = realloc( test_card.image, test_card.width * test_card.height * 3 );
 200                                         memset( test_card.image, 255, test_card.width * test_card.height * 3 );
 201                                         break;
 202                                 case mlt_image_rgb24a:
 203                                         test_card.image = realloc( test_card.image, test_card.width * test_card.height * 4 );
 204                                         memset( test_card.image, 255, test_card.width * test_card.height * 4 );
 205                                         break;
 206                                 case mlt_image_yuv422:
 207                                         test_card.image = realloc( test_card.image, test_card.width * test_card.height * 2 );
 208                                         p = test_card.image;
 209                                         q = test_card.image + test_card.width * test_card.height * 2;
 210                                         while ( p != q )
 211                                         {
 212                                                 *p ++ = 255;
 213                                                 *p ++ = 128;
 214                                         }
 215                                         break;
 216                                 case mlt_image_yuv420p:
 217                                         test_card.image = realloc( test_card.image, test_card.width * test_card.height * 3 / 2 );
 218                                         memset( test_card.image, 255, test_card.width * test_card.height * 3 / 2 );
 219                                         break;
 220                         }
 221                 }
 222
 223                 *width = test_card.width;
 224                 *height = test_card.height;
 225                 *buffer = test_card.image;
 226         }
 227
 228         return 0;
 229 }
 230
 231 uint8_t *mlt_frame_get_alpha_mask( mlt_frame this )
 232 {
 233         if ( this->get_alpha_mask != NULL )
 234                 return this->get_alpha_mask( this );
 235         return test_card.alpha;
 236 }
 237
 238 int mlt_frame_get_audio( mlt_frame this, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
 239 {
 240         if ( this->get_audio != NULL )
 241         {
 242                 return this->get_audio( this, buffer, format, frequency, channels, samples );
 243         }
 244         else
 245         {
 246                 if ( *samples <= 0 )
 247                         *samples = 1920;
 248                 if ( *channels <= 0 )
 249                         *channels = 2;
 250                 if ( *frequency <= 0 )
 251                         *frequency = 48000;
 252                 if ( test_card.audio == NULL || test_card.afmt != *format )
 253                 {
 254                         test_card.afmt = *format;
 255                         test_card.audio = realloc( test_card.audio, *samples * *channels * sizeof( int16_t ) );
 256                         memset( test_card.audio, 0, *samples * *channels * sizeof( int16_t ) );
 257                 }
 258
 259                 *buffer = test_card.audio;
 260         }
 261         return 0;
 262 }
 263
 264 void mlt_frame_close( mlt_frame this )
 265 {
 266         mlt_properties_close( &this->parent );
 267         free( this );
 268 }
 269
 270 /***** convenience functions *****/
 271 #define RGB2YUV(r, g, b, y, u, v)\
 272   y = (306*r + 601*g + 117*b)  >> 10;\
 273   u = ((-172*r - 340*g + 512*b) >> 10)  + 128;\
 274   v = ((512*r - 429*g - 83*b) >> 10) + 128;\
 275   y = y < 0 ? 0 : y;\
 276   u = u < 0 ? 0 : u;\
 277   v = v < 0 ? 0 : v;\
 278   y = y > 255 ? 255 : y;\
 279   u = u > 255 ? 255 : u;\
 280   v = v > 255 ? 255 : v
 281
 282 int mlt_convert_rgb24a_to_yuv422( uint8_t *rgba, int width, int height, int stride, uint8_t *yuv, uint8_t *alpha )
 283 {
 284         int ret = 0;
 285         register int y0, y1, u0, u1, v0, v1;
 286         register int r, g, b;
 287         register uint8_t *d = yuv;
 288         register int i, j;
 289
 290         for ( i = 0; i < height; i++ )
 291         {
 292                 register uint8_t *s = rgba + ( stride * i );
 293                 for ( j = 0; j < ( width / 2 ); j++ )
 294                 {
 295                         r = *s++;
 296                         g = *s++;
 297                         b = *s++;
 298                         *alpha++ = *s++;
 299                         RGB2YUV (r, g, b, y0, u0 , v0);
 300                         r = *s++;
 301                         g = *s++;
 302                         b = *s++;
 303                         *alpha++ = *s++;
 304                         RGB2YUV (r, g, b, y1, u1 , v1);
 305                         *d++ = y0;
 306                         *d++ = (u0+u1) >> 1;
 307                         *d++ = y1;
 308                         *d++ = (v0+v1) >> 1;
 309                 }
 310                 if ( width % 2 )
 311                 {
 312                         r = *s++;
 313                         g = *s++;
 314                         b = *s++;
 315                         *alpha++ = *s++;
 316                         RGB2YUV (r, g, b, y0, u0 , v0);
 317                         *d++ = y0;
 318                         *d++ = u0;
 319                 }
 320         }
 321         return ret;
 322 }
 323
 324 int mlt_convert_rgb24_to_yuv422( uint8_t *rgb, int width, int height, int stride, uint8_t *yuv )
 325 {
 326         int ret = 0;
 327         register int y0, y1, u0, u1, v0, v1;
 328         register int r, g, b;
 329         register uint8_t *d = yuv;
 330         register int i, j;
 331
 332         for ( i = 0; i < height; i++ )
 333         {
 334                 register uint8_t *s = rgb + ( stride * i );
 335                 for ( j = 0; j < ( width / 2 ); j++ )
 336                 {
 337                         r = *s++;
 338                         g = *s++;
 339                         b = *s++;
 340                         RGB2YUV (r, g, b, y0, u0 , v0);
 341                         r = *s++;
 342                         g = *s++;
 343                         b = *s++;
 344                         RGB2YUV (r, g, b, y1, u1 , v1);
 345                         *d++ = y0;
 346                         *d++ = (u0+u1) >> 1;
 347                         *d++ = y1;
 348                         *d++ = (v0+v1) >> 1;
 349                 }
 350                 if ( width % 2 )
 351                 {
 352                         r = *s++;
 353                         g = *s++;
 354                         b = *s++;
 355                         RGB2YUV (r, g, b, y0, u0 , v0);
 356                         *d++ = y0;
 357                         *d++ = u0;
 358                 }
 359         }
 360         return ret;
 361 }
 362
 363 int mlt_convert_yuv420p_to_yuv422( uint8_t *yuv420p, int width, int height, int stride, uint8_t *yuv )
 364 {
 365         int ret = 0;
 366         register int i, j;
 367
 368         int half = width >> 1;
 369
 370         uint8_t *Y = yuv420p;
 371         uint8_t *U = Y + width * height;
 372         uint8_t *V = U + width * height / 4;
 373
 374         register uint8_t *d = yuv;
 375
 376         for ( i = 0; i < height; i++ )
 377         {
 378                 register uint8_t *u = U + ( i / 2 ) * ( half );
 379                 register uint8_t *v = V + ( i / 2 ) * ( half );
 380
 381                 for ( j = 0; j < half; j++ )
 382                 {
 383                         *d ++ = *Y ++;
 384                         *d ++ = *u ++;
 385                         *d ++ = *Y ++;
 386                         *d ++ = *v ++;
 387                 }
 388         }
 389         return ret;
 390 }
 391
 392 int mlt_frame_composite_yuv( mlt_frame this, mlt_frame that, int x, int y, float weight )
 393 {
 394         int ret = 0;
 395         int width_src = 0, height_src = 0;
 396         int width_dest = 0, height_dest = 0;
 397         mlt_image_format format_src = mlt_image_yuv422, format_dest = mlt_image_yuv422;
 398         uint8_t *p_src, *p_dest;
 399         int i, j;
 400         int stride_src;
 401         int stride_dest;
 402         int x_src = 0, y_src = 0;
 403
 404         // optimization point - no work to do
 405         if ( ( x < 0 && -x >= width_src ) || ( y < 0 && -y >= height_src ) )
 406                 return ret;
 407
 408         format_src = mlt_image_yuv422;
 409         format_dest = mlt_image_yuv422;
 410
 411         //fprintf( stderr, "call get_image on frame a\n"), fflush( stderr );
 412         mlt_frame_get_image( this, &p_dest, &format_dest, &width_dest, &height_dest, 1 /* writable */ );
 413         //fprintf( stderr, "call get_image on frame b\n"), fflush( stderr );
 414         mlt_frame_get_image( that, &p_src, &format_src, &width_src, &height_src, 0 /* writable */ );
 415
 416         //fprintf( stderr, "mlt_frame_composite_yuv %dx%d -> %dx%d\n", width_src, height_src, width_dest, height_dest );
 417         //fflush(stderr);
 418         //return ret;
 419         stride_src = width_src * 2;
 420         stride_dest = width_dest * 2;
 421
 422         // crop overlay off the left edge of frame
 423         if ( x < 0 )
 424         {
 425                 x_src = -x;
 426                 width_src -= x_src;
 427                 x = 0;
 428         }
 429
 430         // crop overlay beyond right edge of frame
 431         else if ( x + width_src > width_dest )
 432                 width_src = width_dest - x;
 433
 434         // crop overlay off the top edge of the frame
 435         if ( y < 0 )
 436         {
 437                 y_src = -y;
 438                 height_src -= y_src;
 439         }
 440         // crop overlay below bottom edge of frame
 441         else if ( y + height_src > height_dest )
 442                 height_src = height_dest - y;
 443
 444         // offset pointer into overlay buffer based on cropping
 445         p_src += x_src * 2 + y_src * stride_src;
 446
 447         // offset pointer into frame buffer based upon positive, even coordinates only!
 448 //      if ( interlaced && y % 2 )
 449 //              ++y;
 450         p_dest += ( x < 0 ? 0 : x ) * 2 + ( y < 0 ? 0 : y ) * stride_dest;
 451
 452         // Get the alpha channel of the overlay
 453         uint8_t *p_alpha = mlt_frame_get_alpha_mask( that );
 454
 455         // offset pointer into alpha channel based upon cropping
 456         if ( p_alpha )
 457                 p_alpha += x_src + y_src * stride_src / 2;
 458
 459         uint8_t *p = p_src;
 460         uint8_t *q = p_dest;
 461         uint8_t *o = p_dest;
 462         uint8_t *z = p_alpha;
 463
 464         uint8_t Y;
 465         uint8_t UV;
 466         uint8_t a;
 467         float value;
 468
 469         // now do the compositing only to cropped extents
 470         for ( i = 0; i < height_src; i++ )
 471         {
 472                 p = p_src;
 473                 q = p_dest;
 474                 o = p_dest;
 475                 z = p_alpha;
 476
 477                 for ( j = 0; j < width_src; j ++ )
 478                 {
 479                         Y = *p ++;
 480                         UV = *p ++;
 481                         a = ( z == NULL ) ? 255 : *z ++;
 482                         value = ( weight * ( float ) a / 255.0 );
 483                         *o ++ = (uint8_t)( Y * value + *q++ * ( 1 - value ) );
 484                         *o ++ = (uint8_t)( UV * value + *q++ * ( 1 - value ) );
 485                 }
 486
 487                 p_src += stride_src;
 488                 p_dest += stride_dest;
 489                 if ( p_alpha )
 490                         p_alpha += stride_src / 2;
 491         }
 492
 493         return ret;
 494 }
 495
 496 void *memfill( void *dst, void *src, int l, int elements )
 497 {
 498         int i = 0;
 499         if ( l == 2 )
 500         {
 501                 uint8_t *p = dst;
 502                 uint8_t *src1 = src;
 503                 uint8_t *src2 = src + 1;
 504                 for ( i = 0; i < elements; i ++ )
 505                 {
 506                         *p ++ = *src1;
 507                         *p ++ = *src2;
 508                 }
 509                 dst = p;
 510         }
 511         else
 512         {
 513                 for ( i = 0; i < elements; i ++ )
 514                         dst = memcpy( dst, src, l ) + l;
 515         }
 516         return dst;
 517 }
 518
 519 void mlt_resize_yuv422( uint8_t *output, int owidth, int oheight, uint8_t *input, int iwidth, int iheight )
 520 {
 521         // Calculate strides
 522         int istride = iwidth * 2;
 523         int ostride = owidth * 2;
 524
 525         iwidth = iwidth - ( iwidth % 4 );
 526         owidth = owidth - ( owidth % 4 );
 527         iheight = iheight - ( iheight % 2 );
 528         oheight = oheight - ( oheight % 2 );
 529
 530         // Coordinates (0,0 is middle of output)
 531         int y;
 532
 533         // Calculate ranges
 534         int out_x_range = owidth / 2;
 535         int out_y_range = oheight / 2;
 536         int in_x_range = iwidth / 2 < out_x_range ? iwidth / 2 : out_x_range;
 537         int in_y_range = iheight / 2 < out_y_range ? iheight / 2 : out_y_range;
 538
 539         // Output pointers
 540         uint8_t *out_line = output;
 541         uint8_t *out_ptr = out_line;
 542
 543         // Calculate a middle and possibly invalid pointer in the input
 544         uint8_t *in_middle = input + istride * ( iheight / 2 ) + ( iwidth / 2 ) * 2;
 545         int in_line = - in_y_range * istride - in_x_range * 2;
 546
 547         uint8_t black[ 2 ] = { 16, 128 };
 548
 549         // Loop for the entirety of our output height.
 550         for ( y = - out_y_range; y < out_y_range ; y ++ )
 551         {
 552         // Start at the beginning of the line
 553         out_ptr = out_line;
 554
 555                 if ( abs( y ) < iheight / 2 )
 556                 {
 557                         // Fill the outer part with black
 558                         out_ptr = memfill( out_ptr, black, 2, out_x_range - in_x_range );
 559
 560                 // We're in the input range for this row.
 561                         memcpy( out_ptr, in_middle + in_line, 2 * iwidth );
 562                         out_ptr += 2 * iwidth;
 563
 564                         // Fill the outer part with black
 565                         out_ptr = memfill( out_ptr, black, 2, out_x_range - in_x_range );
 566
 567                 // Move to next input line
 568                 in_line += istride;
 569                 }
 570                 else
 571                 {
 572                         // Fill whole line with black
 573                         out_ptr = memfill( out_ptr, black, 2, owidth );
 574                 }
 575
 576         // Move to next output line
 577         out_line += ostride;
 578         }
 579 }
 580
 581 /** A resizing function for yuv422 frames - this does not rescale, but simply
 582         resizes. It assumes yuv422 images available on the frame so use with care.
 583 */
 584
 585 uint8_t *mlt_frame_resize_yuv422( mlt_frame this, int owidth, int oheight )
 586 {
 587         // Get properties
 588         mlt_properties properties = mlt_frame_properties( this );
 589
 590         // Get the input image, width and height
 591         uint8_t *input = mlt_properties_get_data( properties, "image", NULL );
 592         int iwidth = mlt_properties_get_int( properties, "width" );
 593         int iheight = mlt_properties_get_int( properties, "height" );
 594
 595         // If width and height are correct, don't do anything
 596         if ( iwidth != owidth || iheight != oheight )
 597         {
 598                 // Create the output image
 599                 uint8_t *output = malloc( owidth * oheight * 2 );
 600
 601                 // Call the generic resize
 602                 mlt_resize_yuv422( output, owidth, oheight, input, iwidth, iheight );
 603
 604                 // Now update the frame
 605                 mlt_properties_set_data( properties, "image", output, owidth * oheight * 2, free, NULL );
 606                 mlt_properties_set_int( properties, "width", owidth );
 607                 mlt_properties_set_int( properties, "height", oheight );
 608                 mlt_frame_set_aspect_ratio( this, 4.0/3.0/*( float )owidth / oheight*/ );
 609
 610                 // Return the output
 611                 return output;
 612         }
 613
 614         // No change, return input
 615         return input;
 616 }
 617
 618 /** A rescaling function for yuv422 frames - low quality, and provided for testing
 619         only. It assumes yuv422 images available on the frame so use with care.
 620 */
 621
 622 uint8_t *mlt_frame_rescale_yuv422( mlt_frame this, int owidth, int oheight )
 623 {
 624         // Get properties
 625         mlt_properties properties = mlt_frame_properties( this );
 626
 627         // Get the input image, width and height
 628         uint8_t *input = mlt_properties_get_data( properties, "image", NULL );
 629         int iwidth = mlt_properties_get_int( properties, "width" );
 630         int iheight = mlt_properties_get_int( properties, "height" );
 631
 632         // If width and height are correct, don't do anything
 633         if ( iwidth != owidth || iheight != oheight )
 634         {
 635                 // Create the output image
 636                 uint8_t *output = malloc( owidth * oheight * 2 );
 637
 638                 // Calculate strides
 639                 int istride = iwidth * 2;
 640                 int ostride = owidth * 2;
 641
 642                 iwidth = iwidth - ( iwidth % 4 );
 643
 644         // Coordinates (0,0 is middle of output)
 645         int y, x;
 646
 647                 // Derived coordinates
 648                 int dy, dx;
 649
 650         // Calculate ranges
 651         int out_x_range = owidth / 2;
 652         int out_y_range = oheight / 2;
 653         int in_x_range = iwidth / 2;
 654         int in_y_range = iheight / 2;
 655
 656         // Output pointers
 657         uint8_t *out_line = output;
 658         uint8_t *out_ptr;
 659
 660         // Calculate a middle pointer
 661         uint8_t *in_middle = input + istride * in_y_range + in_x_range * 2;
 662         uint8_t *in_line;
 663                 uint8_t *in_ptr;
 664
 665                 // Generate the affine transform scaling values
 666                 int scale_width = ( iwidth << 16 ) / owidth;
 667                 int scale_height = ( iheight << 16 ) / oheight;
 668
 669         // Loop for the entirety of our output height.
 670         for ( y = - out_y_range; y < out_y_range ; y ++ )
 671         {
 672                         // Calculate the derived y value
 673                         dy = ( scale_height * y ) >> 16;
 674
 675                 // Start at the beginning of the line
 676                 out_ptr = out_line;
 677
 678                 // Pointer to the middle of the input line
 679                 in_line = in_middle + dy * istride;
 680
 681                 // Loop for the entirety of our output row.
 682                 for ( x = - out_x_range; x < out_x_range; x += 1 )
 683                 {
 684                                 // Calculated the derived x
 685                                 dx = ( scale_width * x ) >> 16;
 686
 687                 // We're in the input range for this row.
 688                                 in_ptr = in_line + ( dx << 1 );
 689                 *out_ptr ++ = *in_ptr ++;
 690                                 in_ptr = in_line + ( ( dx >> 1 ) << 2 ) + ( ( x & 1 ) << 1 ) + 1;
 691                 *out_ptr ++ = *in_ptr;
 692                 }
 693
 694                 // Move to next output line
 695                 out_line += ostride;
 696         }
 697
 698                 // Now update the frame
 699                 mlt_properties_set_data( properties, "image", output, owidth * oheight * 2, free, NULL );
 700                 mlt_properties_set_int( properties, "width", owidth );
 701                 mlt_properties_set_int( properties, "height", oheight );
 702
 703                 // Return the output
 704                 return output;
 705         }
 706
 707         // No change, return input
 708         return input;
 709 }
 710
 711 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 )
 712 {
 713         int ret = 0;
 714         int16_t *p_src, *p_dest;
 715         int16_t *src, *dest;
 716         //static int16_t *extra_src = NULL, *extra_dest = NULL;
 717         static int extra_src_samples = 0, extra_dest_samples = 0;
 718         int frequency_src = *frequency, frequency_dest = *frequency;
 719         int channels_src = *channels, channels_dest = *channels;
 720         int samples_src = *samples, samples_dest = *samples;
 721         int i, j;
 722         double d = 0, s = 0;
 723
 724         mlt_frame_get_audio( this, &p_dest, format, &frequency_dest, &channels_dest, &samples_dest );
 725         //fprintf( stderr, "mix: frame dest samples %d channels %d position %lld\n", samples_dest, channels_dest, mlt_properties_get_position( mlt_frame_properties( this ), "_position" ) );
 726         mlt_frame_get_audio( that, &p_src, format, &frequency_src, &channels_src, &samples_src );
 727         //fprintf( stderr, "mix: frame src  samples %d channels %d\n", samples_src, channels_src );
 728         src = p_src;
 729         dest = p_dest;
 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 #endif
 758
 759         // determine number of samples to process
 760         if ( samples_src + extra_src_samples < samples_dest + extra_dest_samples )
 761                 *samples = samples_src + extra_src_samples;
 762         else if ( samples_dest + extra_dest_samples < samples_src + extra_src_samples )
 763                 *samples = samples_dest + extra_dest_samples;
 764
 765         *channels = channels_src < channels_dest ? channels_src : channels_dest;
 766         *buffer = p_dest;
 767         *frequency = frequency_dest;
 768
 769         // Mixdown
 770         for ( i = 0; i < *samples; i++ )
 771         {
 772                 for ( j = 0; j < *channels; j++ )
 773                 {
 774                         if ( j < channels_dest )
 775                                 d = (double) dest[ i * channels_dest + j ];
 776                         if ( j < channels_src )
 777                                 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