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 AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
59 return AVERROR(ENOMEM);
60 return ff_set_common_formats(ctx, fmts_list);
63 #define SET_META(key, format, value) \
64 snprintf(buf, sizeof(buf), format, value); \
65 av_dict_set(metadata, key, buf, 0)
67 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
69 AVFilterContext *ctx = inlink->dst;
70 BlackFrameContext *s = ctx->priv;
73 uint8_t *p = frame->data[0];
74 AVDictionary **metadata;
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];
84 s->last_keyframe = s->frame;
86 pblack = s->nblack * 100 / (inlink->w * inlink->h);
87 if (pblack >= s->bamount) {
88 metadata = &frame->metadata;
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);
96 SET_META("lavfi.blackframe.pblack", "%u", pblack);
101 return ff_filter_frame(inlink->dst->outputs[0], frame);
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 },
116 AVFILTER_DEFINE_CLASS(blackframe);
118 static const AVFilterPad avfilter_vf_blackframe_inputs[] = {
121 .type = AVMEDIA_TYPE_VIDEO,
122 .filter_frame = filter_frame,
127 static const AVFilterPad avfilter_vf_blackframe_outputs[] = {
130 .type = AVMEDIA_TYPE_VIDEO
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,