1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
/*
* Copyright (c) 2012 Stefano Sabatini
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Video black detector, loosely based on blackframe with extended
* syntax and features
*/
#include <float.h>
#include "libavutil/opt.h"
#include "libavutil/timestamp.h"
#include "avfilter.h"
#include "internal.h"
typedef struct {
const AVClass *class;
double black_min_duration_time; ///< minimum duration of detected black, in seconds
int64_t black_min_duration; ///< minimum duration of detected black, expressed in timebase units
int64_t black_start; ///< pts start time of the first black picture
int64_t black_end; ///< pts end time of the last black picture
int64_t last_picref_pts; ///< pts of the last input picture
int black_started;
double picture_black_ratio_th;
double pixel_black_th;
unsigned int pixel_black_th_i;
unsigned int frame_count; ///< frame number
unsigned int nb_black_pixels; ///< number of black pixels counted so far
} BlackDetectContext;
#define OFFSET(x) offsetof(BlackDetectContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption blackdetect_options[] = {
{ "d", "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX, FLAGS },
{ "black_min_duration", "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX, FLAGS },
{ "picture_black_ratio_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS },
{ "pic_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS },
{ "pixel_black_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS },
{ "pix_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS },
{ NULL },
};
AVFILTER_DEFINE_CLASS(blackdetect);
#define YUVJ_FORMATS \
AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P
static enum AVPixelFormat yuvj_formats[] = {
YUVJ_FORMATS, AV_PIX_FMT_NONE
};
static int query_formats(AVFilterContext *ctx)
{
static const enum AVPixelFormat pix_fmts[] = {
AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NV12,
AV_PIX_FMT_NV21, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
YUVJ_FORMATS,
AV_PIX_FMT_NONE
};
ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
return 0;
}
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
BlackDetectContext *blackdetect = ctx->priv;
blackdetect->black_min_duration =
blackdetect->black_min_duration_time / av_q2d(inlink->time_base);
blackdetect->pixel_black_th_i = ff_fmt_is_in(inlink->format, yuvj_formats) ?
// luminance_minimum_value + pixel_black_th * luminance_range_size
blackdetect->pixel_black_th * 255 :
16 + blackdetect->pixel_black_th * (235 - 16);
av_log(blackdetect, AV_LOG_VERBOSE,
"black_min_duration:%s pixel_black_th:%f pixel_black_th_i:%d picture_black_ratio_th:%f\n",
av_ts2timestr(blackdetect->black_min_duration, &inlink->time_base),
blackdetect->pixel_black_th, blackdetect->pixel_black_th_i,
blackdetect->picture_black_ratio_th);
return 0;
}
static void check_black_end(AVFilterContext *ctx)
{
BlackDetectContext *blackdetect = ctx->priv;
AVFilterLink *inlink = ctx->inputs[0];
if ((blackdetect->black_end - blackdetect->black_start) >= blackdetect->black_min_duration) {
av_log(blackdetect, AV_LOG_INFO,
"black_start:%s black_end:%s black_duration:%s\n",
av_ts2timestr(blackdetect->black_start, &inlink->time_base),
av_ts2timestr(blackdetect->black_end, &inlink->time_base),
av_ts2timestr(blackdetect->black_end - blackdetect->black_start, &inlink->time_base));
}
}
static int request_frame(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
BlackDetectContext *blackdetect = ctx->priv;
AVFilterLink *inlink = ctx->inputs[0];
int ret = ff_request_frame(inlink);
if (ret == AVERROR_EOF && blackdetect->black_started) {
// FIXME: black_end should be set to last_picref_pts + last_picref_duration
blackdetect->black_end = blackdetect->last_picref_pts;
check_black_end(ctx);
}
return ret;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
{
AVFilterContext *ctx = inlink->dst;
BlackDetectContext *blackdetect = ctx->priv;
double picture_black_ratio = 0;
const uint8_t *p = picref->data[0];
int x, i;
for (i = 0; i < inlink->h; i++) {
for (x = 0; x < inlink->w; x++)
blackdetect->nb_black_pixels += p[x] <= blackdetect->pixel_black_th_i;
p += picref->linesize[0];
}
picture_black_ratio = (double)blackdetect->nb_black_pixels / (inlink->w * inlink->h);
av_log(ctx, AV_LOG_DEBUG,
"frame:%u picture_black_ratio:%f pts:%s t:%s type:%c\n",
blackdetect->frame_count, picture_black_ratio,
av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base),
av_get_picture_type_char(picref->pict_type));
if (picture_black_ratio >= blackdetect->picture_black_ratio_th) {
if (!blackdetect->black_started) {
/* black starts here */
blackdetect->black_started = 1;
blackdetect->black_start = picref->pts;
}
} else if (blackdetect->black_started) {
/* black ends here */
blackdetect->black_started = 0;
blackdetect->black_end = picref->pts;
check_black_end(ctx);
}
blackdetect->last_picref_pts = picref->pts;
blackdetect->frame_count++;
blackdetect->nb_black_pixels = 0;
return ff_filter_frame(inlink->dst->outputs[0], picref);
}
static const AVFilterPad blackdetect_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_input,
.get_video_buffer = ff_null_get_video_buffer,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad blackdetect_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.request_frame = request_frame,
},
{ NULL }
};
AVFilter avfilter_vf_blackdetect = {
.name = "blackdetect",
.description = NULL_IF_CONFIG_SMALL("Detect video intervals that are (almost) black."),
.priv_size = sizeof(BlackDetectContext),
.query_formats = query_formats,
.inputs = blackdetect_inputs,
.outputs = blackdetect_outputs,
.priv_class = &blackdetect_class,
};
|
