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 "avfilter.h"
35 #include "formats.h"
36 #include "internal.h"
37 #include "video.h"
38 
39 typedef struct {
40  unsigned int bamount;
41  unsigned int bthresh;
42  unsigned int frame;
43  unsigned int nblack;
45 
47 {
48  static const enum AVPixelFormat pix_fmts[] = {
52  };
53 
55  return 0;
56 }
57 
58 static av_cold int init(AVFilterContext *ctx, const char *args)
59 {
60  BlackFrameContext *blackframe = ctx->priv;
61 
62  blackframe->bamount = 98;
63  blackframe->bthresh = 32;
64  blackframe->nblack = 0;
65  blackframe->frame = 0;
66 
67  if (args)
68  sscanf(args, "%u:%u", &blackframe->bamount, &blackframe->bthresh);
69 
70  av_log(ctx, AV_LOG_VERBOSE, "bamount:%u bthresh:%u\n",
71  blackframe->bamount, blackframe->bthresh);
72 
73  if (blackframe->bamount > 100 || blackframe->bthresh > 255) {
74  av_log(ctx, AV_LOG_ERROR, "Too big value for bamount (max is 100) or bthresh (max is 255)\n");
75  return AVERROR(EINVAL);
76  }
77 
78  return 0;
79 }
80 
81 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *frame)
82 {
83  AVFilterContext *ctx = inlink->dst;
84  BlackFrameContext *blackframe = ctx->priv;
85  int x, i;
86  int pblack = 0;
87  uint8_t *p = frame->data[0];
88 
89  for (i = 0; i < frame->video->h; i++) {
90  for (x = 0; x < inlink->w; x++)
91  blackframe->nblack += p[x] < blackframe->bthresh;
92  p += frame->linesize[0];
93  }
94 
95  pblack = blackframe->nblack * 100 / (inlink->w * inlink->h);
96  if (pblack >= blackframe->bamount)
97  av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pos:%"PRId64" pts:%"PRId64" t:%f\n",
98  blackframe->frame, pblack, frame->pos, frame->pts,
99  frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base));
100 
101  blackframe->frame++;
102  blackframe->nblack = 0;
103  return ff_filter_frame(inlink->dst->outputs[0], frame);
104 }
105 
107  {
108  .name = "default",
109  .type = AVMEDIA_TYPE_VIDEO,
110  .get_video_buffer = ff_null_get_video_buffer,
111  .filter_frame = filter_frame,
112  },
113  { NULL }
114 };
115 
117  {
118  .name = "default",
119  .type = AVMEDIA_TYPE_VIDEO
120  },
121  { NULL }
122 };
123 
125  .name = "blackframe",
126  .description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
127 
128  .priv_size = sizeof(BlackFrameContext),
129  .init = init,
130 
132 
133  .inputs = avfilter_vf_blackframe_inputs,
134 
135  .outputs = avfilter_vf_blackframe_outputs,
136 };