libmpcodecs/vf_blackframe.c

   1 /*
   2  * detect frames that are (almost) black
   3  * search for black frames to detect scene transitions
   4  * (c) 2006 Julian Hall
   5  *
   6  * based on code designed for skipping commercials
   7  * (c) 2002-2003 Brian J. Murrell
   8  *
   9  * cleanup, simplify, speedup (c) 2006 by Ivo van Poorten
  10  *
  11  * This file is part of MPlayer.
  12  *
  13  * MPlayer is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * MPlayer is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License along
  24  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  25  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  26  */
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31
  32 #include "config.h"
  33 #include "mp_msg.h"
  34
  35 #include "img_format.h"
  36 #include "mp_image.h"
  37 #include "vf.h"
  38
  39 struct vf_priv_s {
  40     unsigned int bamount, bthresh, frame, lastkeyframe;
  41 };
  42
  43 static int config(struct vf_instance *vf, int width, int height, int d_width,
  44                     int d_height, unsigned int flags, unsigned int outfmt) {
  45     return vf_next_config(vf,width,height,d_width,d_height,flags,outfmt);
  46 }
  47
  48 static int query_format(struct vf_instance *vf, unsigned fmt) {
  49     switch(fmt) {
  50     case IMGFMT_YVU9:
  51     case IMGFMT_IF09:
  52     case IMGFMT_YV12:
  53     case IMGFMT_I420:
  54     case IMGFMT_IYUV:
  55     case IMGFMT_CLPL:
  56     case IMGFMT_Y800:
  57     case IMGFMT_Y8:
  58     case IMGFMT_NV12:
  59     case IMGFMT_NV21:
  60     case IMGFMT_444P:
  61     case IMGFMT_422P:
  62     case IMGFMT_411P:
  63     case IMGFMT_HM12:
  64         return vf_next_query_format(vf, fmt);
  65     }
  66     return 0;
  67 }
  68
  69 static int put_image(struct vf_instance *vf, mp_image_t *mpi, double pts){
  70     mp_image_t *dmpi;
  71     int x, y;
  72     int nblack=0, pblack=0;
  73     unsigned char *yplane = mpi->planes[0];
  74     unsigned int ystride = mpi->stride[0];
  75     int pict_type = mpi->pict_type;
  76     int w = mpi->w, h = mpi->h;
  77     int bthresh = vf->priv->bthresh;
  78     int bamount = vf->priv->bamount;
  79     static const char *const picttypes[4] = { "unknown", "I", "P", "B" };
  80
  81     for (y=1; y<=h; y++) {
  82             for (x=0; x<w; x++)
  83             nblack += yplane[x] < bthresh;
  84             pblack = nblack*100/(w*y);
  85             if (pblack < bamount) break;
  86         yplane += ystride;
  87     }
  88
  89     if (pict_type > 3 || pict_type < 0) pict_type = 0;
  90     if (pict_type == 1) vf->priv->lastkeyframe = vf->priv->frame;
  91
  92     if (pblack >= bamount)
  93             mp_msg(MSGT_VFILTER, MSGL_INFO,"vf_blackframe: %u, %i%%, %s (I:%u)\n",
  94                                 vf->priv->frame, pblack, picttypes[pict_type],
  95                                 vf->priv->lastkeyframe);
  96
  97     vf->priv->frame++;
  98
  99     dmpi = vf_get_image(vf->next, mpi->imgfmt, MP_IMGTYPE_EXPORT, 0,
 100                                                     mpi->width, mpi->height);
 101     dmpi->planes[0] = mpi->planes[0];
 102     dmpi->stride[0] = mpi->stride[0];
 103     dmpi->planes[1] = mpi->planes[1];
 104     dmpi->stride[1] = mpi->stride[1];
 105     dmpi->planes[2] = mpi->planes[2];
 106     dmpi->stride[2] = mpi->stride[2];
 107
 108     vf_clone_mpi_attributes(dmpi, mpi);
 109
 110     return vf_next_put_image(vf, dmpi, pts);
 111 }
 112
 113 static int control(struct vf_instance *vf, int request, void* data){
 114     return vf_next_control(vf,request,data);
 115 }
 116
 117 static void uninit(struct vf_instance *vf) {
 118     free(vf->priv);
 119 }
 120
 121 static int vf_open(vf_instance_t *vf, char *args){
 122     vf->priv = malloc(sizeof(struct vf_priv_s));
 123     if (!vf->priv) return 0;
 124
 125     vf->config = config;
 126     vf->put_image = put_image;
 127     vf->control = control;
 128     vf->uninit = uninit;
 129     vf->query_format = query_format;
 130
 131     vf->priv->bamount = 98;
 132     vf->priv->bthresh = 0x20;
 133     vf->priv->frame = 0;
 134     vf->priv->lastkeyframe = 0;
 135
 136     if (args)
 137             sscanf(args, "%u:%u", &vf->priv->bamount, &vf->priv->bthresh);
 138     return 1;
 139 }
 140
 141 const vf_info_t vf_info_blackframe = {
 142     "detects black frames",
 143     "blackframe",
 144     "Brian J. Murrell, Julian Hall, Ivo van Poorten",
 145     "Useful for detecting scene transitions",
 146     vf_open,
 147     NULL
 148 };