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
41 double picture_black_ratio_th;
42 double pixel_black_th;
43 unsigned int pixel_black_th_i;
45 unsigned int frame_count; ///< frame number
46 unsigned int nb_black_pixels; ///< number of black pixels counted so far
49 #define OFFSET(x) offsetof(BlackDetectContext, x)
50 static const AVOption blackdetect_options[] = {
51 { "d", "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX},
52 { "black_min_duration", "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX},
53 { "picture_black_ratio_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1},
54 { "pic_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1},
55 { "pixel_black_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1},
56 { "pix_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1},
60 static const AVClass blackdetect_class = {
61 .class_name = "BlackDetectContext",
62 .item_name = av_default_item_name,
63 .option = blackdetect_options,
66 #define YUVJ_FORMATS \
67 PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ444P, PIX_FMT_YUVJ440P
69 static enum PixelFormat yuvj_formats[] = {
70 YUVJ_FORMATS, PIX_FMT_NONE
73 static int query_formats(AVFilterContext *ctx)
75 static const enum PixelFormat pix_fmts[] = {
76 PIX_FMT_YUV410P, PIX_FMT_YUV420P, PIX_FMT_GRAY8, PIX_FMT_NV12,
77 PIX_FMT_NV21, PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV411P,
82 avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));
86 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
89 BlackDetectContext *blackdetect = ctx->priv;
91 blackdetect->class = &blackdetect_class;
92 av_opt_set_defaults(blackdetect);
94 if ((ret = av_set_options_string(blackdetect, args, "=", ":")) < 0) {
95 av_log(ctx, AV_LOG_ERROR, "Error parsing options string: '%s'\n", args);
102 static int config_input(AVFilterLink *inlink)
104 AVFilterContext *ctx = inlink->dst;
105 BlackDetectContext *blackdetect = ctx->priv;
107 blackdetect->black_min_duration =
108 blackdetect->black_min_duration_time / av_q2d(inlink->time_base);
110 blackdetect->pixel_black_th_i = ff_fmt_is_in(inlink->format, yuvj_formats) ?
111 // luminance_minimum_value + pixel_black_th * luminance_range_size
112 blackdetect->pixel_black_th * 255 :
113 16 + blackdetect->pixel_black_th * (235 - 16);
115 av_log(blackdetect, AV_LOG_INFO,
116 "black_min_duration:%s pixel_black_th:%f pixel_black_th_i:%d picture_black_ratio_th:%f\n",
117 av_ts2timestr(blackdetect->black_min_duration, &inlink->time_base),
118 blackdetect->pixel_black_th, blackdetect->pixel_black_th_i,
119 blackdetect->picture_black_ratio_th);
123 static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
125 AVFilterContext *ctx = inlink->dst;
126 BlackDetectContext *blackdetect = ctx->priv;
127 AVFilterBufferRef *picref = inlink->cur_buf;
129 const uint8_t *p = picref->data[0] + y * picref->linesize[0];
131 for (i = 0; i < h; i++) {
132 for (x = 0; x < inlink->w; x++)
133 blackdetect->nb_black_pixels += p[x] <= blackdetect->pixel_black_th_i;
134 p += picref->linesize[0];
137 avfilter_draw_slice(ctx->outputs[0], y, h, slice_dir);
140 static void end_frame(AVFilterLink *inlink)
142 AVFilterContext *ctx = inlink->dst;
143 BlackDetectContext *blackdetect = ctx->priv;
144 AVFilterBufferRef *picref = inlink->cur_buf;
145 double picture_black_ratio = 0;
147 picture_black_ratio = (double)blackdetect->nb_black_pixels / (inlink->w * inlink->h);
149 av_log(ctx, AV_LOG_DEBUG,
150 "frame:%u picture_black_ratio:%f pos:%"PRId64" pts:%s t:%s type:%c\n",
151 blackdetect->frame_count, picture_black_ratio,
152 picref->pos, av_ts2str(picref->pts),
153 av_ts2timestr(blackdetect->black_start, &inlink->time_base),
154 av_get_picture_type_char(picref->video->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;
167 if ((blackdetect->black_end - blackdetect->black_start) >= blackdetect->black_min_duration) {
168 av_log(blackdetect, AV_LOG_INFO,
169 "black_start:%s black_end:%s black_duration:%s\n",
170 av_ts2timestr(blackdetect->black_start, &inlink->time_base),
171 av_ts2timestr(blackdetect->black_end, &inlink->time_base),
172 av_ts2timestr(blackdetect->black_end - blackdetect->black_start, &inlink->time_base));
176 blackdetect->frame_count++;
177 blackdetect->nb_black_pixels = 0;
178 avfilter_unref_buffer(picref);
179 avfilter_end_frame(inlink->dst->outputs[0]);
182 AVFilter avfilter_vf_blackdetect = {
183 .name = "blackdetect",
184 .description = NULL_IF_CONFIG_SMALL("Detect video intervals that are (almost) black."),
185 .priv_size = sizeof(BlackDetectContext),
187 .query_formats = query_formats,
189 .inputs = (const AVFilterPad[]) {
191 .type = AVMEDIA_TYPE_VIDEO,
192 .config_props = config_input,
193 .draw_slice = draw_slice,
194 .get_video_buffer = avfilter_null_get_video_buffer,
195 .start_frame = ff_null_start_frame_keep_ref,
196 .end_frame = end_frame, },
200 .outputs = (const AVFilterPad[]) {
202 .type = AVMEDIA_TYPE_VIDEO },