1/* 2 * Copyright (c) 2012 Stefano Sabatini 3 * 4 * This file is part of FFmpeg. 5 * 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. 10 * 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. 15 * 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 19 */ 20 21/** 22 * @file 23 * Video black detector, loosely based on blackframe with extended 24 * syntax and features 25 */ 26 27#include <float.h> 28#include "libavutil/opt.h" 29#include "libavutil/timestamp.h" 30#include "avfilter.h" 31#include "internal.h" 32 33typedef struct { 34 const AVClass *class; 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 40 int black_started; 41 42 double picture_black_ratio_th; 43 double pixel_black_th; 44 unsigned int pixel_black_th_i; 45 46 unsigned int nb_black_pixels; ///< number of black pixels counted so far 47} BlackDetectContext; 48 49#define OFFSET(x) offsetof(BlackDetectContext, x) 50#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM 51 52static 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 }, 59 { NULL } 60}; 61 62AVFILTER_DEFINE_CLASS(blackdetect); 63 64#define YUVJ_FORMATS \ 65 AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P 66 67static enum AVPixelFormat yuvj_formats[] = { 68 YUVJ_FORMATS, AV_PIX_FMT_NONE 69}; 70 71static int query_formats(AVFilterContext *ctx) 72{ 73 static const enum AVPixelFormat pix_fmts[] = { 74 AV_PIX_FMT_GRAY8, 75 AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P, 76 AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, 77 AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P, 78 AV_PIX_FMT_NV12, AV_PIX_FMT_NV21, 79 YUVJ_FORMATS, 80 AV_PIX_FMT_NONE 81 }; 82 83 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts)); 84 return 0; 85} 86 87static int config_input(AVFilterLink *inlink) 88{ 89 AVFilterContext *ctx = inlink->dst; 90 BlackDetectContext *blackdetect = ctx->priv; 91 92 blackdetect->black_min_duration = 93 blackdetect->black_min_duration_time / av_q2d(inlink->time_base); 94 95 blackdetect->pixel_black_th_i = ff_fmt_is_in(inlink->format, yuvj_formats) ? 96 // luminance_minimum_value + pixel_black_th * luminance_range_size 97 blackdetect->pixel_black_th * 255 : 98 16 + blackdetect->pixel_black_th * (235 - 16); 99 100 av_log(blackdetect, AV_LOG_VERBOSE, 101 "black_min_duration:%s pixel_black_th:%f pixel_black_th_i:%d picture_black_ratio_th:%f\n", 102 av_ts2timestr(blackdetect->black_min_duration, &inlink->time_base), 103 blackdetect->pixel_black_th, blackdetect->pixel_black_th_i, 104 blackdetect->picture_black_ratio_th); 105 return 0; 106} 107 108static void check_black_end(AVFilterContext *ctx) 109{ 110 BlackDetectContext *blackdetect = ctx->priv; 111 AVFilterLink *inlink = ctx->inputs[0]; 112 113 if ((blackdetect->black_end - blackdetect->black_start) >= blackdetect->black_min_duration) { 114 av_log(blackdetect, AV_LOG_INFO, 115 "black_start:%s black_end:%s black_duration:%s\n", 116 av_ts2timestr(blackdetect->black_start, &inlink->time_base), 117 av_ts2timestr(blackdetect->black_end, &inlink->time_base), 118 av_ts2timestr(blackdetect->black_end - blackdetect->black_start, &inlink->time_base)); 119 } 120} 121 122static int request_frame(AVFilterLink *outlink) 123{ 124 AVFilterContext *ctx = outlink->src; 125 BlackDetectContext *blackdetect = ctx->priv; 126 AVFilterLink *inlink = ctx->inputs[0]; 127 int ret = ff_request_frame(inlink); 128 129 if (ret == AVERROR_EOF && blackdetect->black_started) { 130 // FIXME: black_end should be set to last_picref_pts + last_picref_duration 131 blackdetect->black_end = blackdetect->last_picref_pts; 132 check_black_end(ctx); 133 } 134 return ret; 135} 136 137// TODO: document metadata 138static int filter_frame(AVFilterLink *inlink, AVFrame *picref) 139{ 140 AVFilterContext *ctx = inlink->dst; 141 BlackDetectContext *blackdetect = ctx->priv; 142 double picture_black_ratio = 0; 143 const uint8_t *p = picref->data[0]; 144 int x, i; 145 146 for (i = 0; i < inlink->h; i++) { 147 for (x = 0; x < inlink->w; x++) 148 blackdetect->nb_black_pixels += p[x] <= blackdetect->pixel_black_th_i; 149 p += picref->linesize[0]; 150 } 151 152 picture_black_ratio = (double)blackdetect->nb_black_pixels / (inlink->w * inlink->h); 153 154 av_log(ctx, AV_LOG_DEBUG, 155 "frame:%"PRId64" picture_black_ratio:%f pts:%s t:%s type:%c\n", 156 inlink->frame_count, picture_black_ratio, 157 av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base), 158 av_get_picture_type_char(picref->pict_type)); 159 160 if (picture_black_ratio >= blackdetect->picture_black_ratio_th) { 161 if (!blackdetect->black_started) { 162 /* black starts here */ 163 blackdetect->black_started = 1; 164 blackdetect->black_start = picref->pts; 165 av_dict_set(avpriv_frame_get_metadatap(picref), "lavfi.black_start", 166 av_ts2timestr(blackdetect->black_start, &inlink->time_base), 0); 167 } 168 } else if (blackdetect->black_started) { 169 /* black ends here */ 170 blackdetect->black_started = 0; 171 blackdetect->black_end = picref->pts; 172 check_black_end(ctx); 173 av_dict_set(avpriv_frame_get_metadatap(picref), "lavfi.black_end", 174 av_ts2timestr(blackdetect->black_end, &inlink->time_base), 0); 175 } 176 177 blackdetect->last_picref_pts = picref->pts; 178 blackdetect->nb_black_pixels = 0; 179 return ff_filter_frame(inlink->dst->outputs[0], picref); 180} 181 182static const AVFilterPad blackdetect_inputs[] = { 183 { 184 .name = "default", 185 .type = AVMEDIA_TYPE_VIDEO, 186 .config_props = config_input, 187 .filter_frame = filter_frame, 188 }, 189 { NULL } 190}; 191 192static const AVFilterPad blackdetect_outputs[] = { 193 { 194 .name = "default", 195 .type = AVMEDIA_TYPE_VIDEO, 196 .request_frame = request_frame, 197 }, 198 { NULL } 199}; 200 201AVFilter ff_vf_blackdetect = { 202 .name = "blackdetect", 203 .description = NULL_IF_CONFIG_SMALL("Detect video intervals that are (almost) black."), 204 .priv_size = sizeof(BlackDetectContext), 205 .query_formats = query_formats, 206 .inputs = blackdetect_inputs, 207 .outputs = blackdetect_outputs, 208 .priv_class = &blackdetect_class, 209}; 210