libavfilter/phase_template.c

   1 /*
   2  * Copyright (c) 2004 Ville Saari
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg 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 along
  17  * with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "libavutil/avassert.h"
  22 #include "avfilter.h"
  23 #include "video.h"
  24
  25 #undef pixel
  26 #undef accumulator
  27 #if DEPTH == 8
  28 #define pixel uint8_t
  29 #define accumulator int
  30 #else
  31 #define pixel uint16_t
  32 #define accumulator int64_t
  33 #endif
  34
  35 #define fn3(a,b)   a##_##b
  36 #define fn2(a,b)   fn3(a,b)
  37 #define fn(a)      fn2(a, DEPTH)
  38
  39 /*
  40  * This macro interpolates the value of both fields at a point halfway
  41  * between lines and takes the squared difference. In field resolution
  42  * the point is a quarter pixel below a line in one field and a quarter
  43  * pixel above a line in other.
  44  *
  45  * (The result is actually multiplied by 25)
  46  */
  47 #define DIFF(a, as, b, bs) ((t) = ((*(a) - (b)[bs]) * 4) + (a)[(as) * 2] - (b)[-(bs)], (t) * (t))
  48
  49 /*
  50  * Find which field combination has the smallest average squared difference
  51  * between the fields.
  52  */
  53 static enum PhaseMode fn(analyze_plane)(void *ctx, enum PhaseMode mode, AVFrame *old, AVFrame *new)
  54 {
  55     double bdiff, tdiff, pdiff;
  56
  57     if (mode == AUTO) {
  58         mode = (new->flags & AV_FRAME_FLAG_INTERLACED) ? (new->flags & AV_FRAME_FLAG_TOP_FIELD_FIRST) ?
  59                TOP_FIRST : BOTTOM_FIRST : PROGRESSIVE;
  60     } else if (mode == AUTO_ANALYZE) {
  61         mode = (new->flags & AV_FRAME_FLAG_INTERLACED) ? (new->flags & AV_FRAME_FLAG_TOP_FIELD_FIRST) ?
  62                TOP_FIRST_ANALYZE : BOTTOM_FIRST_ANALYZE : FULL_ANALYZE;
  63     }
  64
  65     if (mode <= BOTTOM_FIRST) {
  66         bdiff = pdiff = tdiff = 65536.0;
  67     } else {
  68         const double factor = 1. / (25. * (1 << (DEPTH - 8)) * (1 << (DEPTH - 8)));
  69         const int ns = new->linesize[0] / sizeof(pixel);
  70         const int os = old->linesize[0] / sizeof(pixel);
  71         const pixel *nptr = (pixel *)new->data[0];
  72         const pixel *optr = (pixel *)old->data[0];
  73         const int h = new->height;
  74         const int w = new->width;
  75         accumulator bdif, tdif, pdif;
  76         double scale;
  77
  78         int top = 0, t;
  79         const pixel *rend, *end = nptr + (h - 2) * ns;
  80
  81         bdiff = pdiff = tdiff = 0.0;
  82
  83         nptr += ns;
  84         optr += os;
  85         while (nptr < end) {
  86             pdif = tdif = bdif = 0;
  87
  88             switch (mode) {
  89             case TOP_FIRST_ANALYZE:
  90                 if (top) {
  91                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
  92                         pdif += DIFF(nptr, ns, nptr, ns);
  93                         tdif += DIFF(nptr, ns, optr, os);
  94                     }
  95                 } else {
  96                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
  97                         pdif += DIFF(nptr, ns, nptr, ns);
  98                         tdif += DIFF(optr, os, nptr, ns);
  99                     }
 100                 }
 101                 break;
 102             case BOTTOM_FIRST_ANALYZE:
 103                 if (top) {
 104                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
 105                         pdif += DIFF(nptr, ns, nptr, ns);
 106                         bdif += DIFF(optr, os, nptr, ns);
 107                     }
 108                 } else {
 109                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
 110                         pdif += DIFF(nptr, ns, nptr, ns);
 111                         bdif += DIFF(nptr, ns, optr, os);
 112                     }
 113                 }
 114                 break;
 115             case ANALYZE:
 116                 if (top) {
 117                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
 118                         tdif += DIFF(nptr, ns, optr, os);
 119                         bdif += DIFF(optr, os, nptr, ns);
 120                     }
 121                 } else {
 122                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
 123                         bdif += DIFF(nptr, ns, optr, os);
 124                         tdif += DIFF(optr, os, nptr, ns);
 125                     }
 126                 }
 127                 break;
 128             case FULL_ANALYZE:
 129                 if (top) {
 130                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
 131                         pdif += DIFF(nptr, ns, nptr, ns);
 132                         tdif += DIFF(nptr, ns, optr, os);
 133                         bdif += DIFF(optr, os, nptr, ns);
 134                     }
 135                 } else {
 136                     for (rend = nptr + w; nptr < rend; nptr++, optr++) {
 137                         pdif += DIFF(nptr, ns, nptr, ns);
 138                         bdif += DIFF(nptr, ns, optr, os);
 139                         tdif += DIFF(optr, os, nptr, ns);
 140                     }
 141                 }
 142                 break;
 143             default:
 144                 av_assert0(0);
 145             }
 146
 147             pdiff += (double)pdif;
 148             tdiff += (double)tdif;
 149             bdiff += (double)bdif;
 150             nptr += ns - w;
 151             optr += os - w;
 152             top ^= 1;
 153         }
 154
 155         scale = 1.0 / (w * (h - 3)) * factor;
 156         pdiff *= scale;
 157         tdiff *= scale;
 158         bdiff *= scale;
 159
 160         if (mode == TOP_FIRST_ANALYZE) {
 161             bdiff = 65536.0;
 162         } else if (mode == BOTTOM_FIRST_ANALYZE) {
 163             tdiff = 65536.0;
 164         } else if (mode == ANALYZE) {
 165             pdiff = 65536.0;
 166         }
 167
 168         if (bdiff < pdiff && bdiff < tdiff) {
 169             mode = BOTTOM_FIRST;
 170         } else if (tdiff < pdiff && tdiff < bdiff) {
 171             mode = TOP_FIRST;
 172         } else {
 173             mode = PROGRESSIVE;
 174         }
 175     }
 176
 177     av_log(ctx, AV_LOG_DEBUG, "mode=%c tdiff=%f bdiff=%f pdiff=%f\n",
 178            mode == BOTTOM_FIRST ? 'b' : mode == TOP_FIRST ? 't' : 'p',
 179            tdiff, bdiff, pdiff);
 180     return mode;
 181 }