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 frame_count; ///< frame number
47 unsigned int nb_black_pixels; ///< number of black pixels counted so far
50 #define OFFSET(x) offsetof(BlackDetectContext, x)
51 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
53 static const AVOption blackdetect_options[] = {
54 { "d", "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX, FLAGS },
55 { "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 },
56 { "picture_black_ratio_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS },
57 { "pic_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS },
58 { "pixel_black_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS },
59 { "pix_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS },
63 AVFILTER_DEFINE_CLASS(blackdetect);
65 #define YUVJ_FORMATS \
66 AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P
68 static enum AVPixelFormat yuvj_formats[] = {
69 YUVJ_FORMATS, AV_PIX_FMT_NONE
72 static int query_formats(AVFilterContext *ctx)
74 static const enum AVPixelFormat pix_fmts[] = {
75 AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NV12,
76 AV_PIX_FMT_NV21, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
81 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
85 static av_cold int init(AVFilterContext *ctx, const char *args)
88 BlackDetectContext *blackdetect = ctx->priv;
90 blackdetect->class = &blackdetect_class;
91 av_opt_set_defaults(blackdetect);
93 if ((ret = av_set_options_string(blackdetect, args, "=", ":")) < 0)
99 static int config_input(AVFilterLink *inlink)
101 AVFilterContext *ctx = inlink->dst;
102 BlackDetectContext *blackdetect = ctx->priv;
104 blackdetect->black_min_duration =
105 blackdetect->black_min_duration_time / av_q2d(inlink->time_base);
107 blackdetect->pixel_black_th_i = ff_fmt_is_in(inlink->format, yuvj_formats) ?
108 // luminance_minimum_value + pixel_black_th * luminance_range_size
109 blackdetect->pixel_black_th * 255 :
110 16 + blackdetect->pixel_black_th * (235 - 16);
112 av_log(blackdetect, AV_LOG_VERBOSE,
113 "black_min_duration:%s pixel_black_th:%f pixel_black_th_i:%d picture_black_ratio_th:%f\n",
114 av_ts2timestr(blackdetect->black_min_duration, &inlink->time_base),
115 blackdetect->pixel_black_th, blackdetect->pixel_black_th_i,
116 blackdetect->picture_black_ratio_th);
120 static void check_black_end(AVFilterContext *ctx)
122 BlackDetectContext *blackdetect = ctx->priv;
123 AVFilterLink *inlink = ctx->inputs[0];
125 if ((blackdetect->black_end - blackdetect->black_start) >= blackdetect->black_min_duration) {
126 av_log(blackdetect, AV_LOG_INFO,
127 "black_start:%s black_end:%s black_duration:%s\n",
128 av_ts2timestr(blackdetect->black_start, &inlink->time_base),
129 av_ts2timestr(blackdetect->black_end, &inlink->time_base),
130 av_ts2timestr(blackdetect->black_end - blackdetect->black_start, &inlink->time_base));
134 static int request_frame(AVFilterLink *outlink)
136 AVFilterContext *ctx = outlink->src;
137 BlackDetectContext *blackdetect = ctx->priv;
138 AVFilterLink *inlink = ctx->inputs[0];
139 int ret = ff_request_frame(inlink);
141 if (ret == AVERROR_EOF && blackdetect->black_started) {
142 // FIXME: black_end should be set to last_picref_pts + last_picref_duration
143 blackdetect->black_end = blackdetect->last_picref_pts;
144 check_black_end(ctx);
149 static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
151 AVFilterContext *ctx = inlink->dst;
152 BlackDetectContext *blackdetect = ctx->priv;
153 double picture_black_ratio = 0;
154 const uint8_t *p = picref->data[0];
157 for (i = 0; i < inlink->h; i++) {
158 for (x = 0; x < inlink->w; x++)
159 blackdetect->nb_black_pixels += p[x] <= blackdetect->pixel_black_th_i;
160 p += picref->linesize[0];
163 picture_black_ratio = (double)blackdetect->nb_black_pixels / (inlink->w * inlink->h);
165 av_log(ctx, AV_LOG_DEBUG,
166 "frame:%u picture_black_ratio:%f pts:%s t:%s type:%c\n",
167 blackdetect->frame_count, picture_black_ratio,
168 av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base),
169 av_get_picture_type_char(picref->pict_type));
171 if (picture_black_ratio >= blackdetect->picture_black_ratio_th) {
172 if (!blackdetect->black_started) {
173 /* black starts here */
174 blackdetect->black_started = 1;
175 blackdetect->black_start = picref->pts;
177 } else if (blackdetect->black_started) {
178 /* black ends here */
179 blackdetect->black_started = 0;
180 blackdetect->black_end = picref->pts;
181 check_black_end(ctx);
184 blackdetect->last_picref_pts = picref->pts;
185 blackdetect->frame_count++;
186 blackdetect->nb_black_pixels = 0;
187 return ff_filter_frame(inlink->dst->outputs[0], picref);
190 static const AVFilterPad blackdetect_inputs[] = {
193 .type = AVMEDIA_TYPE_VIDEO,
194 .config_props = config_input,
195 .get_video_buffer = ff_null_get_video_buffer,
196 .filter_frame = filter_frame,
201 static const AVFilterPad blackdetect_outputs[] = {
204 .type = AVMEDIA_TYPE_VIDEO,
205 .request_frame = request_frame,
210 AVFilter avfilter_vf_blackdetect = {
211 .name = "blackdetect",
212 .description = NULL_IF_CONFIG_SMALL("Detect video intervals that are (almost) black."),
213 .priv_size = sizeof(BlackDetectContext),
215 .query_formats = query_formats,
216 .inputs = blackdetect_inputs,
217 .outputs = blackdetect_outputs,
218 .priv_class = &blackdetect_class,