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
7 * This file is part of FFmpeg.
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.
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.
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.
26 * Search for black frames to detect scene transitions.
27 * Ported from MPlayer libmpcodecs/vf_blackframe.c.
33 #include "libavutil/internal.h"
34 #include "libavutil/opt.h"
40 typedef struct BlackFrameContext
{
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
49 static int query_formats(AVFilterContext
*ctx
)
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
,
57 ff_set_common_formats(ctx
, ff_make_format_list(pix_fmts
));
61 #define SET_META(key, format, value) \
62 snprintf(buf, sizeof(buf), format, value); \
63 av_dict_set(metadata, key, buf, 0)
65 static int filter_frame(AVFilterLink
*inlink
, AVFrame
*frame
)
67 AVFilterContext
*ctx
= inlink
->dst
;
68 BlackFrameContext
*s
= ctx
->priv
;
71 uint8_t *p
= frame
->data
[0];
72 AVDictionary
**metadata
;
75 for (i
= 0; i
< frame
->height
; i
++) {
76 for (x
= 0; x
< inlink
->w
; x
++)
77 s
->nblack
+= p
[x
] < s
->bthresh
;
78 p
+= frame
->linesize
[0];
82 s
->last_keyframe
= s
->frame
;
84 pblack
= s
->nblack
* 100 / (inlink
->w
* inlink
->h
);
85 if (pblack
>= s
->bamount
) {
86 metadata
= avpriv_frame_get_metadatap(frame
);
88 av_log(ctx
, AV_LOG_INFO
, "frame:%u pblack:%u pts:%"PRId64
" t:%f "
89 "type:%c last_keyframe:%d\n",
90 s
->frame
, pblack
, frame
->pts
,
91 frame
->pts
== AV_NOPTS_VALUE
? -1 : frame
->pts
* av_q2d(inlink
->time_base
),
92 av_get_picture_type_char(frame
->pict_type
), s
->last_keyframe
);
94 SET_META("lavfi.blackframe.pblack", "%u", pblack
);
99 return ff_filter_frame(inlink
->dst
->outputs
[0], frame
);
102 #define OFFSET(x) offsetof(BlackFrameContext, x)
103 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
104 static const AVOption blackframe_options
[] = {
105 { "amount", "Percentage of the pixels that have to be below the threshold "
106 "for the frame to be considered black.", OFFSET(bamount
), AV_OPT_TYPE_INT
, { .i64
= 98 }, 0, 100, FLAGS
},
107 { "threshold", "threshold below which a pixel value is considered black",
108 OFFSET(bthresh
), AV_OPT_TYPE_INT
, { .i64
= 32 }, 0, 255, FLAGS
},
109 { "thresh", "threshold below which a pixel value is considered black",
110 OFFSET(bthresh
), AV_OPT_TYPE_INT
, { .i64
= 32 }, 0, 255, FLAGS
},
114 AVFILTER_DEFINE_CLASS(blackframe
);
116 static const AVFilterPad avfilter_vf_blackframe_inputs
[] = {
119 .type
= AVMEDIA_TYPE_VIDEO
,
120 .filter_frame
= filter_frame
,
125 static const AVFilterPad avfilter_vf_blackframe_outputs
[] = {
128 .type
= AVMEDIA_TYPE_VIDEO
133 AVFilter ff_vf_blackframe
= {
134 .name
= "blackframe",
135 .description
= NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
136 .priv_size
= sizeof(BlackFrameContext
),
137 .priv_class
= &blackframe_class
,
138 .query_formats
= query_formats
,
139 .inputs
= avfilter_vf_blackframe_inputs
,
140 .outputs
= avfilter_vf_blackframe_outputs
,