Libav
vf_blackframe.c
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1 /*
2  * Copyright (c) 2010 Stefano Sabatini
3  * Copyright (c) 2006 Ivo van Poorten
4  * Copyright (c) 2006 Julian Hall
5  * Copyright (c) 2002-2003 Brian J. Murrell
6  *
7  * This file is part of Libav.
8  *
9  * Libav is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * Libav is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License along
20  * with Libav; if not, write to the Free Software Foundation, Inc.,
21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
22  */
23 
30 #include <stdio.h>
31 #include <inttypes.h>
32 
33 #include "libavutil/internal.h"
34 #include "libavutil/opt.h"
35 
36 #include "avfilter.h"
37 #include "formats.h"
38 #include "internal.h"
39 #include "video.h"
40 
41 typedef struct {
42  const AVClass *class;
43  int bamount;
44  int bthresh;
45  unsigned int frame;
46  unsigned int nblack;
48 
50 {
51  static const enum AVPixelFormat pix_fmts[] = {
55  };
56 
58  return 0;
59 }
60 
61 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
62 {
63  AVFilterContext *ctx = inlink->dst;
64  BlackFrameContext *s = ctx->priv;
65  int x, i;
66  int pblack = 0;
67  uint8_t *p = frame->data[0];
68 
69  for (i = 0; i < frame->height; i++) {
70  for (x = 0; x < inlink->w; x++)
71  s->nblack += p[x] < s->bthresh;
72  p += frame->linesize[0];
73  }
74 
75  pblack = s->nblack * 100 / (inlink->w * inlink->h);
76  if (pblack >= s->bamount)
77  av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pts:%"PRId64" t:%f\n",
78  s->frame, pblack, frame->pts,
79  frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base));
80 
81  s->frame++;
82  s->nblack = 0;
83  return ff_filter_frame(inlink->dst->outputs[0], frame);
84 }
85 
86 #define OFFSET(x) offsetof(BlackFrameContext, x)
87 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM
88 static const AVOption options[] = {
89  { "amount", "Percentage of the pixels that have to be below the threshold "
90  "for the frame to be considered black.", OFFSET(bamount), AV_OPT_TYPE_INT, { .i64 = 98 }, 0, 100, FLAGS },
91  { "threshold", "threshold below which a pixel value is considered black",
92  OFFSET(bthresh), AV_OPT_TYPE_INT, { .i64 = 32 }, 0, INT_MAX, FLAGS },
93  { NULL },
94 };
95 
96 static const AVClass blackframe_class = {
97  .class_name = "blackframe",
98  .item_name = av_default_item_name,
99  .option = options,
100  .version = LIBAVUTIL_VERSION_INT,
101 };
102 
104  {
105  .name = "default",
106  .type = AVMEDIA_TYPE_VIDEO,
107  .get_video_buffer = ff_null_get_video_buffer,
108  .filter_frame = filter_frame,
109  },
110  { NULL }
111 };
112 
114  {
115  .name = "default",
116  .type = AVMEDIA_TYPE_VIDEO
117  },
118  { NULL }
119 };
120 
122  .name = "blackframe",
123  .description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
124 
125  .priv_size = sizeof(BlackFrameContext),
126  .priv_class = &blackframe_class,
127 
129 
130  .inputs = avfilter_vf_blackframe_inputs,
131 
132  .outputs = avfilter_vf_blackframe_outputs,
133 };