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

   1 /*
   2  * filter_deinterlace.c -- deinterlace filter
   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 "filter_deinterlace.h"
  22
  23 #include <framework/mlt_frame.h>
  24
  25 #include <string.h>
  26 #include <stdlib.h>
  27
  28 /** Deinterlace class.
  29 */
  30
  31 typedef struct
  32 {
  33         struct mlt_filter_s parent;
  34 }
  35 filter_deinterlace;
  36
  37 /* Linear Blend filter - C version contributed by Rogerio Brito.
  38    This algorithm has the same interface as the other functions.
  39
  40    The destination "screen" (pdst) is constructed from the source
  41    screen (psrc[0]) line by line.
  42
  43    The i-th line of the destination screen is the average of 3 lines
  44    from the source screen: the (i-1)-th, i-th and (i+1)-th lines, with
  45    the i-th line having weight 2 in the computation.
  46
  47    Remarks:
  48    * each line on pdst doesn't depend on previous lines;
  49    * due to the way the algorithm is defined, the first & last lines of the
  50      screen aren't deinterlaced.
  51
  52 */
  53 static void deinterlace_yuv( uint8_t *pdst, uint8_t *psrc, int width, int height )
  54 {
  55         register int x, y;
  56         register uint8_t *l0, *l1, *l2, *l3;
  57
  58         l0 = pdst;              /* target line */
  59         l1 = psrc;              /* 1st source line */
  60         l2 = l1 + width;        /* 2nd source line = line that follows l1 */
  61         l3 = l2 + width;        /* 3rd source line = line that follows l2 */
  62
  63         /* Copy the first line */
  64         memcpy(l0, l1, width);
  65         l0 += width;
  66
  67         for (y = 1; y < height-1; ++y)
  68         {
  69                 /* computes avg of: l1 + 2*l2 + l3 */
  70                 for (x = 0; x < width; ++x)
  71                         l0[x] = (l1[x] + (l2[x]<<1) + l3[x]) >> 2;
  72
  73                 /* updates the line pointers */
  74                 l1 = l2; l2 = l3; l3 += width;
  75                 l0 += width;
  76         }
  77
  78         /* Copy the last line */
  79         memcpy(l0, l1, width);
  80 }
  81
  82 /** Do it :-).
  83 */
  84
  85 static int filter_get_image( mlt_frame this, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
  86 {
  87         mlt_frame_get_image( this, image, format, width, height, 1 );
  88         deinterlace_yuv( *image, *image, *width * 2, *height );
  89         mlt_properties_set_int( mlt_frame_properties( this ), "progressive", 1 );
  90         return 0;
  91 }
  92
  93 /** Deinterlace filter processing - this should be lazy evaluation here...
  94 */
  95
  96 static mlt_frame deinterlace_process( mlt_filter this, mlt_frame frame )
  97 {
  98         mlt_frame_push_get_image( frame, filter_get_image );
  99         return frame;
 100 }
 101
 102 /** Constructor for the filter.
 103 */
 104
 105 mlt_filter filter_deinterlace_init( void *arg )
 106 {
 107         filter_deinterlace *this = calloc( sizeof( filter_deinterlace ), 1 );
 108         if ( this != NULL )
 109         {
 110                 mlt_filter filter = &this->parent;
 111                 mlt_filter_init( filter, this );
 112                 filter->process = deinterlace_process;
 113                 return &this->parent;
 114         }
 115         return NULL;
 116 }
 117