2 * Copyright (c) 2012 Stefano Sabatini
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * Video black detector, loosely based on blackframe with extended
28 #include "libavutil/opt.h"
29 #include "libavutil/timestamp.h"
35 double black_min_duration_time; ///< minimum duration of detected black, in seconds
36 int64_t black_min_duration; ///< minimum duration of detected black, expressed in timebase units
37 int64_t black_start; ///< pts start time of the first black picture
38 int64_t black_end; ///< pts end time of the last black picture
39 int64_t last_picref_pts; ///< pts of the last input picture
42 double picture_black_ratio_th;
43 double pixel_black_th;
44 unsigned int pixel_black_th_i;
46 unsigned int nb_black_pixels; ///< number of black pixels counted so far
49 #define OFFSET(x) offsetof(BlackDetectContext, x)
50 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
52 static const AVOption blackdetect_options[] = {
53 { "d", "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX, FLAGS },
54 { "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 },
55 { "picture_black_ratio_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS },
56 { "pic_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS },
57 { "pixel_black_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS },
58 { "pix_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS },
62 AVFILTER_DEFINE_CLASS(blackdetect);
64 #define YUVJ_FORMATS \
65 AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P
67 static enum AVPixelFormat yuvj_formats[] = {
68 YUVJ_FORMATS, AV_PIX_FMT_NONE
71 static int query_formats(AVFilterContext *ctx)
73 static const enum AVPixelFormat pix_fmts[] = {
74 AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NV12,
75 AV_PIX_FMT_NV21, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
80 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
84 static int config_input(AVFilterLink *inlink)
86 AVFilterContext *ctx = inlink->dst;
87 BlackDetectContext *blackdetect = ctx->priv;
89 blackdetect->black_min_duration =
90 blackdetect->black_min_duration_time / av_q2d(inlink->time_base);
92 blackdetect->pixel_black_th_i = ff_fmt_is_in(inlink->format, yuvj_formats) ?
93 // luminance_minimum_value + pixel_black_th * luminance_range_size
94 blackdetect->pixel_black_th * 255 :
95 16 + blackdetect->pixel_black_th * (235 - 16);
97 av_log(blackdetect, AV_LOG_VERBOSE,
98 "black_min_duration:%s pixel_black_th:%f pixel_black_th_i:%d picture_black_ratio_th:%f\n",
99 av_ts2timestr(blackdetect->black_min_duration, &inlink->time_base),
100 blackdetect->pixel_black_th, blackdetect->pixel_black_th_i,
101 blackdetect->picture_black_ratio_th);
105 static void check_black_end(AVFilterContext *ctx)
107 BlackDetectContext *blackdetect = ctx->priv;
108 AVFilterLink *inlink = ctx->inputs[0];
110 if ((blackdetect->black_end - blackdetect->black_start) >= blackdetect->black_min_duration) {
111 av_log(blackdetect, AV_LOG_INFO,
112 "black_start:%s black_end:%s black_duration:%s\n",
113 av_ts2timestr(blackdetect->black_start, &inlink->time_base),
114 av_ts2timestr(blackdetect->black_end, &inlink->time_base),
115 av_ts2timestr(blackdetect->black_end - blackdetect->black_start, &inlink->time_base));
119 static int request_frame(AVFilterLink *outlink)
121 AVFilterContext *ctx = outlink->src;
122 BlackDetectContext *blackdetect = ctx->priv;
123 AVFilterLink *inlink = ctx->inputs[0];
124 int ret = ff_request_frame(inlink);
126 if (ret == AVERROR_EOF && blackdetect->black_started) {
127 // FIXME: black_end should be set to last_picref_pts + last_picref_duration
128 blackdetect->black_end = blackdetect->last_picref_pts;
129 check_black_end(ctx);
134 static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
136 AVFilterContext *ctx = inlink->dst;
137 BlackDetectContext *blackdetect = ctx->priv;
138 double picture_black_ratio = 0;
139 const uint8_t *p = picref->data[0];
142 for (i = 0; i < inlink->h; i++) {
143 for (x = 0; x < inlink->w; x++)
144 blackdetect->nb_black_pixels += p[x] <= blackdetect->pixel_black_th_i;
145 p += picref->linesize[0];
148 picture_black_ratio = (double)blackdetect->nb_black_pixels / (inlink->w * inlink->h);
150 av_log(ctx, AV_LOG_DEBUG,
151 "frame:%"PRId64" picture_black_ratio:%f pts:%s t:%s type:%c\n",
152 inlink->frame_count, picture_black_ratio,
153 av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base),
154 av_get_picture_type_char(picref->pict_type));
156 if (picture_black_ratio >= blackdetect->picture_black_ratio_th) {
157 if (!blackdetect->black_started) {
158 /* black starts here */
159 blackdetect->black_started = 1;
160 blackdetect->black_start = picref->pts;
162 } else if (blackdetect->black_started) {
163 /* black ends here */
164 blackdetect->black_started = 0;
165 blackdetect->black_end = picref->pts;
166 check_black_end(ctx);
169 blackdetect->last_picref_pts = picref->pts;
170 blackdetect->nb_black_pixels = 0;
171 return ff_filter_frame(inlink->dst->outputs[0], picref);
174 static const AVFilterPad blackdetect_inputs[] = {
177 .type = AVMEDIA_TYPE_VIDEO,
178 .config_props = config_input,
179 .get_video_buffer = ff_null_get_video_buffer,
180 .filter_frame = filter_frame,
185 static const AVFilterPad blackdetect_outputs[] = {
188 .type = AVMEDIA_TYPE_VIDEO,
189 .request_frame = request_frame,
194 AVFilter avfilter_vf_blackdetect = {
195 .name = "blackdetect",
196 .description = NULL_IF_CONFIG_SMALL("Detect video intervals that are (almost) black."),
197 .priv_size = sizeof(BlackDetectContext),
198 .query_formats = query_formats,
199 .inputs = blackdetect_inputs,
200 .outputs = blackdetect_outputs,
201 .priv_class = &blackdetect_class,