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 static const AVOption blackdetect_options[] = {
52 { "d", "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX},
53 { "black_min_duration", "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX},
54 { "picture_black_ratio_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1},
55 { "pic_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1},
56 { "pixel_black_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1},
57 { "pix_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1},
61 AVFILTER_DEFINE_CLASS(blackdetect);
63 #define YUVJ_FORMATS \
64 PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ444P, PIX_FMT_YUVJ440P
66 static enum PixelFormat yuvj_formats[] = {
67 YUVJ_FORMATS, PIX_FMT_NONE
70 static int query_formats(AVFilterContext *ctx)
72 static const enum PixelFormat pix_fmts[] = {
73 PIX_FMT_YUV410P, PIX_FMT_YUV420P, PIX_FMT_GRAY8, PIX_FMT_NV12,
74 PIX_FMT_NV21, PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV411P,
79 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
83 static av_cold int init(AVFilterContext *ctx, const char *args)
86 BlackDetectContext *blackdetect = ctx->priv;
88 blackdetect->class = &blackdetect_class;
89 av_opt_set_defaults(blackdetect);
91 if ((ret = av_set_options_string(blackdetect, args, "=", ":")) < 0)
97 static int config_input(AVFilterLink *inlink)
99 AVFilterContext *ctx = inlink->dst;
100 BlackDetectContext *blackdetect = ctx->priv;
102 blackdetect->black_min_duration =
103 blackdetect->black_min_duration_time / av_q2d(inlink->time_base);
105 blackdetect->pixel_black_th_i = ff_fmt_is_in(inlink->format, yuvj_formats) ?
106 // luminance_minimum_value + pixel_black_th * luminance_range_size
107 blackdetect->pixel_black_th * 255 :
108 16 + blackdetect->pixel_black_th * (235 - 16);
110 av_log(blackdetect, AV_LOG_VERBOSE,
111 "black_min_duration:%s pixel_black_th:%f pixel_black_th_i:%d picture_black_ratio_th:%f\n",
112 av_ts2timestr(blackdetect->black_min_duration, &inlink->time_base),
113 blackdetect->pixel_black_th, blackdetect->pixel_black_th_i,
114 blackdetect->picture_black_ratio_th);
118 static void check_black_end(AVFilterContext *ctx)
120 BlackDetectContext *blackdetect = ctx->priv;
121 AVFilterLink *inlink = ctx->inputs[0];
123 if ((blackdetect->black_end - blackdetect->black_start) >= blackdetect->black_min_duration) {
124 av_log(blackdetect, AV_LOG_INFO,
125 "black_start:%s black_end:%s black_duration:%s\n",
126 av_ts2timestr(blackdetect->black_start, &inlink->time_base),
127 av_ts2timestr(blackdetect->black_end, &inlink->time_base),
128 av_ts2timestr(blackdetect->black_end - blackdetect->black_start, &inlink->time_base));
132 static int request_frame(AVFilterLink *outlink)
134 AVFilterContext *ctx = outlink->src;
135 BlackDetectContext *blackdetect = ctx->priv;
136 AVFilterLink *inlink = ctx->inputs[0];
137 int ret = ff_request_frame(inlink);
139 if (ret == AVERROR_EOF && blackdetect->black_started) {
140 // FIXME: black_end should be set to last_picref_pts + last_picref_duration
141 blackdetect->black_end = blackdetect->last_picref_pts;
142 check_black_end(ctx);
147 static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
149 AVFilterContext *ctx = inlink->dst;
150 BlackDetectContext *blackdetect = ctx->priv;
151 AVFilterBufferRef *picref = inlink->cur_buf;
153 const uint8_t *p = picref->data[0] + y * picref->linesize[0];
155 for (i = 0; i < h; i++) {
156 for (x = 0; x < inlink->w; x++)
157 blackdetect->nb_black_pixels += p[x] <= blackdetect->pixel_black_th_i;
158 p += picref->linesize[0];
161 return ff_draw_slice(ctx->outputs[0], y, h, slice_dir);
164 static int end_frame(AVFilterLink *inlink)
166 AVFilterContext *ctx = inlink->dst;
167 BlackDetectContext *blackdetect = ctx->priv;
168 AVFilterBufferRef *picref = inlink->cur_buf;
169 double picture_black_ratio = 0;
171 picture_black_ratio = (double)blackdetect->nb_black_pixels / (inlink->w * inlink->h);
173 av_log(ctx, AV_LOG_DEBUG,
174 "frame:%u picture_black_ratio:%f pos:%"PRId64" pts:%s t:%s type:%c\n",
175 blackdetect->frame_count, picture_black_ratio,
176 picref->pos, av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base),
177 av_get_picture_type_char(picref->video->pict_type));
179 if (picture_black_ratio >= blackdetect->picture_black_ratio_th) {
180 if (!blackdetect->black_started) {
181 /* black starts here */
182 blackdetect->black_started = 1;
183 blackdetect->black_start = picref->pts;
185 } else if (blackdetect->black_started) {
186 /* black ends here */
187 blackdetect->black_started = 0;
188 blackdetect->black_end = picref->pts;
189 check_black_end(ctx);
192 blackdetect->last_picref_pts = picref->pts;
193 blackdetect->frame_count++;
194 blackdetect->nb_black_pixels = 0;
195 return ff_end_frame(inlink->dst->outputs[0]);
198 AVFilter avfilter_vf_blackdetect = {
199 .name = "blackdetect",
200 .description = NULL_IF_CONFIG_SMALL("Detect video intervals that are (almost) black."),
201 .priv_size = sizeof(BlackDetectContext),
203 .query_formats = query_formats,
205 .inputs = (const AVFilterPad[]) {
207 .type = AVMEDIA_TYPE_VIDEO,
208 .config_props = config_input,
209 .draw_slice = draw_slice,
210 .get_video_buffer = ff_null_get_video_buffer,
211 .start_frame = ff_null_start_frame,
212 .end_frame = end_frame, },
216 .outputs = (const AVFilterPad[]) {
218 .type = AVMEDIA_TYPE_VIDEO,
219 .request_frame = request_frame, },