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
|
/*
* Copyright (c) 2010 Stefano Sabatini
* Copyright (c) 2006 Ivo van Poorten
* Copyright (c) 2006 Julian Hall
* Copyright (c) 2002-2003 Brian J. Murrell
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Libav 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with Libav; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/**
* @file
* Search for black frames to detect scene transitions.
* Ported from MPlayer libmpcodecs/vf_blackframe.c.
*/
#include <stdio.h>
#include <inttypes.h>
#include "libavutil/internal.h"
#include "libavutil/opt.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
typedef struct BlackFrameContext {
const AVClass *class;
int bamount; ///< black amount
int bthresh; ///< black threshold
unsigned int frame; ///< frame number
unsigned int nblack; ///< number of black pixels counted so far
} BlackFrameContext;
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,
AV_PIX_FMT_NONE
};
ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
{
AVFilterContext *ctx = inlink->dst;
BlackFrameContext *s = ctx->priv;
int x, i;
int pblack = 0;
uint8_t *p = frame->data[0];
for (i = 0; i < frame->height; i++) {
for (x = 0; x < inlink->w; x++)
s->nblack += p[x] < s->bthresh;
p += frame->linesize[0];
}
pblack = s->nblack * 100 / (inlink->w * inlink->h);
if (pblack >= s->bamount)
av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pts:%"PRId64" t:%f\n",
s->frame, pblack, frame->pts,
frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base));
s->frame++;
s->nblack = 0;
return ff_filter_frame(inlink->dst->outputs[0], frame);
}
#define OFFSET(x) offsetof(BlackFrameContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM
static const AVOption options[] = {
{ "amount", "Percentage of the pixels that have to be below the threshold "
"for the frame to be considered black.", OFFSET(bamount), AV_OPT_TYPE_INT, { .i64 = 98 }, 0, 100, FLAGS },
{ "threshold", "threshold below which a pixel value is considered black",
OFFSET(bthresh), AV_OPT_TYPE_INT, { .i64 = 32 }, 0, INT_MAX, FLAGS },
{ NULL },
};
static const AVClass blackframe_class = {
.class_name = "blackframe",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
static const AVFilterPad avfilter_vf_blackframe_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.get_video_buffer = ff_null_get_video_buffer,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad avfilter_vf_blackframe_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO
},
{ NULL }
};
AVFilter ff_vf_blackframe = {
.name = "blackframe",
.description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
.priv_size = sizeof(BlackFrameContext),
.priv_class = &blackframe_class,
.query_formats = query_formats,
.inputs = avfilter_vf_blackframe_inputs,
.outputs = avfilter_vf_blackframe_outputs,
};
|
