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 int config_input(AVFilterLink *inlink)
87 AVFilterContext *ctx = inlink->dst;
88 BlackDetectContext *blackdetect = ctx->priv;
90 blackdetect->black_min_duration =
91 blackdetect->black_min_duration_time / av_q2d(inlink->time_base);
93 blackdetect->pixel_black_th_i = ff_fmt_is_in(inlink->format, yuvj_formats) ?
94 // luminance_minimum_value + pixel_black_th * luminance_range_size
95 blackdetect->pixel_black_th * 255 :
96 16 + blackdetect->pixel_black_th * (235 - 16);
98 av_log(blackdetect, AV_LOG_VERBOSE,
99 "black_min_duration:%s pixel_black_th:%f pixel_black_th_i:%d picture_black_ratio_th:%f\n",
100 av_ts2timestr(blackdetect->black_min_duration, &inlink->time_base),
101 blackdetect->pixel_black_th, blackdetect->pixel_black_th_i,
102 blackdetect->picture_black_ratio_th);
106 static void check_black_end(AVFilterContext *ctx)
108 BlackDetectContext *blackdetect = ctx->priv;
109 AVFilterLink *inlink = ctx->inputs[0];
111 if ((blackdetect->black_end - blackdetect->black_start) >= blackdetect->black_min_duration) {
112 av_log(blackdetect, AV_LOG_INFO,
113 "black_start:%s black_end:%s black_duration:%s\n",
114 av_ts2timestr(blackdetect->black_start, &inlink->time_base),
115 av_ts2timestr(blackdetect->black_end, &inlink->time_base),
116 av_ts2timestr(blackdetect->black_end - blackdetect->black_start, &inlink->time_base));
120 static int request_frame(AVFilterLink *outlink)
122 AVFilterContext *ctx = outlink->src;
123 BlackDetectContext *blackdetect = ctx->priv;
124 AVFilterLink *inlink = ctx->inputs[0];
125 int ret = ff_request_frame(inlink);
127 if (ret == AVERROR_EOF && blackdetect->black_started) {
128 // FIXME: black_end should be set to last_picref_pts + last_picref_duration
129 blackdetect->black_end = blackdetect->last_picref_pts;
130 check_black_end(ctx);
135 static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
137 AVFilterContext *ctx = inlink->dst;
138 BlackDetectContext *blackdetect = ctx->priv;
139 double picture_black_ratio = 0;
140 const uint8_t *p = picref->data[0];
143 for (i = 0; i < inlink->h; i++) {
144 for (x = 0; x < inlink->w; x++)
145 blackdetect->nb_black_pixels += p[x] <= blackdetect->pixel_black_th_i;
146 p += picref->linesize[0];
149 picture_black_ratio = (double)blackdetect->nb_black_pixels / (inlink->w * inlink->h);
151 av_log(ctx, AV_LOG_DEBUG,
152 "frame:%u picture_black_ratio:%f pts:%s t:%s type:%c\n",
153 blackdetect->frame_count, picture_black_ratio,
154 av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base),
155 av_get_picture_type_char(picref->pict_type));
157 if (picture_black_ratio >= blackdetect->picture_black_ratio_th) {
158 if (!blackdetect->black_started) {
159 /* black starts here */
160 blackdetect->black_started = 1;
161 blackdetect->black_start = picref->pts;
163 } else if (blackdetect->black_started) {
164 /* black ends here */
165 blackdetect->black_started = 0;
166 blackdetect->black_end = picref->pts;
167 check_black_end(ctx);
170 blackdetect->last_picref_pts = picref->pts;
171 blackdetect->frame_count++;
172 blackdetect->nb_black_pixels = 0;
173 return ff_filter_frame(inlink->dst->outputs[0], picref);
176 static const AVFilterPad blackdetect_inputs[] = {
179 .type = AVMEDIA_TYPE_VIDEO,
180 .config_props = config_input,
181 .get_video_buffer = ff_null_get_video_buffer,
182 .filter_frame = filter_frame,
187 static const AVFilterPad blackdetect_outputs[] = {
190 .type = AVMEDIA_TYPE_VIDEO,
191 .request_frame = request_frame,
196 AVFilter avfilter_vf_blackdetect = {
197 .name = "blackdetect",
198 .description = NULL_IF_CONFIG_SMALL("Detect video intervals that are (almost) black."),
199 .priv_size = sizeof(BlackDetectContext),
200 .query_formats = query_formats,
201 .inputs = blackdetect_inputs,
202 .outputs = blackdetect_outputs,
203 .priv_class = &blackdetect_class,