| 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 | |
| 33 | typedef 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 | |
| 52 | static 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 | |
| 62 | AVFILTER_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 | |
| 67 | static const enum AVPixelFormat yuvj_formats[] = { |
| 68 | YUVJ_FORMATS, AV_PIX_FMT_NONE |
| 69 | }; |
| 70 | |
| 71 | static 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 | |
| 87 | static 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 | |
| 108 | static 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 | |
| 122 | static 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 |
| 138 | static 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 | |
| 182 | static 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 | |
| 192 | static const AVFilterPad blackdetect_outputs[] = { |
| 193 | { |
| 194 | .name = "default", |
| 195 | .type = AVMEDIA_TYPE_VIDEO, |
| 196 | .request_frame = request_frame, |
| 197 | }, |
| 198 | { NULL } |
| 199 | }; |
| 200 | |
| 201 | AVFilter 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 | }; |