path: root/libavfilter/vf_blackframe.c (plain)
blob: 9fe2a429429aa28640650c5485e00263fd3f3e19

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 FFmpeg.
8	*
9	* FFmpeg 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	* FFmpeg 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 FFmpeg; if not, write to the Free Software Foundation, Inc.,
21	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
22	*/
23
24	/**
25	* @file
26	* Search for black frames to detect scene transitions.
27	* Ported from MPlayer libmpcodecs/vf_blackframe.c.
28	*/
29
30	#include <stdio.h>
31	#include <inttypes.h>
32
33	#include "libavutil/internal.h"
34	#include "libavutil/opt.h"
35	#include "avfilter.h"
36	#include "formats.h"
37	#include "internal.h"
38	#include "video.h"
39
40	typedef struct BlackFrameContext {
41	const AVClass *class;
42	int bamount; ///< black amount
43	int bthresh; ///< black threshold
44	unsigned int frame; ///< frame number
45	unsigned int nblack; ///< number of black pixels counted so far
46	unsigned int last_keyframe; ///< frame number of the last received key-frame
47	} BlackFrameContext;
48
49	static int query_formats(AVFilterContext *ctx)
50	{
51	static const enum AVPixelFormat pix_fmts[] = {
52	AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NV12,
53	AV_PIX_FMT_NV21, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
54	AV_PIX_FMT_NONE
55	};
56
57	AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
58	if (!fmts_list)
59	return AVERROR(ENOMEM);
60	return ff_set_common_formats(ctx, fmts_list);
61	}
62
63	#define SET_META(key, format, value) \
64	snprintf(buf, sizeof(buf), format, value); \
65	av_dict_set(metadata, key, buf, 0)
66
67	static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
68	{
69	AVFilterContext *ctx = inlink->dst;
70	BlackFrameContext *s = ctx->priv;
71	int x, i;
72	int pblack = 0;
73	uint8_t *p = frame->data[0];
74	AVDictionary **metadata;
75	char buf[32];
76
77	for (i = 0; i < frame->height; i++) {
78	for (x = 0; x < inlink->w; x++)
79	s->nblack += p[x] < s->bthresh;
80	p += frame->linesize[0];
81	}
82
83	if (frame->key_frame)
84	s->last_keyframe = s->frame;
85
86	pblack = s->nblack * 100 / (inlink->w * inlink->h);
87	if (pblack >= s->bamount) {
88	metadata = avpriv_frame_get_metadatap(frame);
89
90	av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pts:%"PRId64" t:%f "
91	"type:%c last_keyframe:%d\n",
92	s->frame, pblack, frame->pts,
93	frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base),
94	av_get_picture_type_char(frame->pict_type), s->last_keyframe);
95
96	SET_META("lavfi.blackframe.pblack", "%u", pblack);
97	}
98
99	s->frame++;
100	s->nblack = 0;
101	return ff_filter_frame(inlink->dst->outputs[0], frame);
102	}
103
104	#define OFFSET(x) offsetof(BlackFrameContext, x)
105	#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
106	static const AVOption blackframe_options[] = {
107	{ "amount", "percentage of the pixels that have to be below the threshold "
108	"for the frame to be considered black", OFFSET(bamount), AV_OPT_TYPE_INT, { .i64 = 98 }, 0, 100, FLAGS },
109	{ "threshold", "threshold below which a pixel value is considered black",
110	OFFSET(bthresh), AV_OPT_TYPE_INT, { .i64 = 32 }, 0, 255, FLAGS },
111	{ "thresh", "threshold below which a pixel value is considered black",
112	OFFSET(bthresh), AV_OPT_TYPE_INT, { .i64 = 32 }, 0, 255, FLAGS },
113	{ NULL }
114	};
115
116	AVFILTER_DEFINE_CLASS(blackframe);
117
118	static const AVFilterPad avfilter_vf_blackframe_inputs[] = {
119	{
120	.name = "default",
121	.type = AVMEDIA_TYPE_VIDEO,
122	.filter_frame = filter_frame,
123	},
124	{ NULL }
125	};
126
127	static const AVFilterPad avfilter_vf_blackframe_outputs[] = {
128	{
129	.name = "default",
130	.type = AVMEDIA_TYPE_VIDEO
131	},
132	{ NULL }
133	};
134
135	AVFilter ff_vf_blackframe = {
136	.name = "blackframe",
137	.description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
138	.priv_size = sizeof(BlackFrameContext),
139	.priv_class = &blackframe_class,
140	.query_formats = query_formats,
141	.inputs = avfilter_vf_blackframe_inputs,
142	.outputs = avfilter_vf_blackframe_outputs,
143	};
144