/* * Copyright (c) 2012 Stefano Sabatini * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * Video black detector, loosely based on blackframe with extended * syntax and features */ #include #include "libavutil/opt.h" #include "libavutil/timestamp.h" #include "avfilter.h" #include "internal.h" typedef struct { const AVClass *class; double black_min_duration_time; ///< minimum duration of detected black, in seconds int64_t black_min_duration; ///< minimum duration of detected black, expressed in timebase units int64_t black_start; ///< pts start time of the first black picture int64_t black_end; ///< pts end time of the last black picture int64_t last_picref_pts; ///< pts of the last input picture int black_started; double picture_black_ratio_th; double pixel_black_th; unsigned int pixel_black_th_i; unsigned int frame_count; ///< frame number unsigned int nb_black_pixels; ///< number of black pixels counted so far } BlackDetectContext; #define OFFSET(x) offsetof(BlackDetectContext, x) static const AVOption blackdetect_options[] = { { "d", "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX}, { "black_min_duration", "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX}, { "picture_black_ratio_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1}, { "pic_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1}, { "pixel_black_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1}, { "pix_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1}, { NULL }, }; static const AVClass blackdetect_class = { .class_name = "blackdetect", .item_name = av_default_item_name, .option = blackdetect_options, .version = LIBAVUTIL_VERSION_INT, .category = AV_CLASS_CATEGORY_FILTER, }; #define YUVJ_FORMATS \ PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ444P, PIX_FMT_YUVJ440P static enum PixelFormat yuvj_formats[] = { YUVJ_FORMATS, PIX_FMT_NONE }; static int query_formats(AVFilterContext *ctx) { static const enum PixelFormat pix_fmts[] = { PIX_FMT_YUV410P, PIX_FMT_YUV420P, PIX_FMT_GRAY8, PIX_FMT_NV12, PIX_FMT_NV21, PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV411P, YUVJ_FORMATS, PIX_FMT_NONE }; ff_set_common_formats(ctx, ff_make_format_list(pix_fmts)); return 0; } static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque) { int ret; BlackDetectContext *blackdetect = ctx->priv; blackdetect->class = &blackdetect_class; av_opt_set_defaults(blackdetect); if ((ret = av_set_options_string(blackdetect, args, "=", ":")) < 0) { av_log(ctx, AV_LOG_ERROR, "Error parsing options string: '%s'\n", args); return ret; } return 0; } static int config_input(AVFilterLink *inlink) { AVFilterContext *ctx = inlink->dst; BlackDetectContext *blackdetect = ctx->priv; blackdetect->black_min_duration = blackdetect->black_min_duration_time / av_q2d(inlink->time_base); blackdetect->pixel_black_th_i = ff_fmt_is_in(inlink->format, yuvj_formats) ? // luminance_minimum_value + pixel_black_th * luminance_range_size blackdetect->pixel_black_th * 255 : 16 + blackdetect->pixel_black_th * (235 - 16); av_log(blackdetect, AV_LOG_INFO, "black_min_duration:%s pixel_black_th:%f pixel_black_th_i:%d picture_black_ratio_th:%f\n", av_ts2timestr(blackdetect->black_min_duration, &inlink->time_base), blackdetect->pixel_black_th, blackdetect->pixel_black_th_i, blackdetect->picture_black_ratio_th); return 0; } static void check_black_end(AVFilterContext *ctx) { BlackDetectContext *blackdetect = ctx->priv; AVFilterLink *inlink = ctx->inputs[0]; if ((blackdetect->black_end - blackdetect->black_start) >= blackdetect->black_min_duration) { av_log(blackdetect, AV_LOG_INFO, "black_start:%s black_end:%s black_duration:%s\n", av_ts2timestr(blackdetect->black_start, &inlink->time_base), av_ts2timestr(blackdetect->black_end, &inlink->time_base), av_ts2timestr(blackdetect->black_end - blackdetect->black_start, &inlink->time_base)); } } static int request_frame(AVFilterLink *outlink) { AVFilterContext *ctx = outlink->src; BlackDetectContext *blackdetect = ctx->priv; AVFilterLink *inlink = ctx->inputs[0]; int ret = avfilter_request_frame(inlink); if (ret == AVERROR_EOF && blackdetect->black_started) { // FIXME: black_end should be set to last_picref_pts + last_picref_duration blackdetect->black_end = blackdetect->last_picref_pts; check_black_end(ctx); } return ret; } static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir) { AVFilterContext *ctx = inlink->dst; BlackDetectContext *blackdetect = ctx->priv; AVFilterBufferRef *picref = inlink->cur_buf; int x, i; const uint8_t *p = picref->data[0] + y * picref->linesize[0]; for (i = 0; i < h; i++) { for (x = 0; x < inlink->w; x++) blackdetect->nb_black_pixels += p[x] <= blackdetect->pixel_black_th_i; p += picref->linesize[0]; } ff_draw_slice(ctx->outputs[0], y, h, slice_dir); } static void end_frame(AVFilterLink *inlink) { AVFilterContext *ctx = inlink->dst; BlackDetectContext *blackdetect = ctx->priv; AVFilterBufferRef *picref = inlink->cur_buf; double picture_black_ratio = 0; picture_black_ratio = (double)blackdetect->nb_black_pixels / (inlink->w * inlink->h); av_log(ctx, AV_LOG_DEBUG, "frame:%u picture_black_ratio:%f pos:%"PRId64" pts:%s t:%s type:%c\n", blackdetect->frame_count, picture_black_ratio, picref->pos, av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base), av_get_picture_type_char(picref->video->pict_type)); if (picture_black_ratio >= blackdetect->picture_black_ratio_th) { if (!blackdetect->black_started) { /* black starts here */ blackdetect->black_started = 1; blackdetect->black_start = picref->pts; } } else if (blackdetect->black_started) { /* black ends here */ blackdetect->black_started = 0; blackdetect->black_end = picref->pts; check_black_end(ctx); } blackdetect->last_picref_pts = picref->pts; blackdetect->frame_count++; blackdetect->nb_black_pixels = 0; avfilter_unref_buffer(picref); ff_end_frame(inlink->dst->outputs[0]); } AVFilter avfilter_vf_blackdetect = { .name = "blackdetect", .description = NULL_IF_CONFIG_SMALL("Detect video intervals that are (almost) black."), .priv_size = sizeof(BlackDetectContext), .init = init, .query_formats = query_formats, .inputs = (const AVFilterPad[]) { { .name = "default", .type = AVMEDIA_TYPE_VIDEO, .config_props = config_input, .draw_slice = draw_slice, .get_video_buffer = ff_null_get_video_buffer, .start_frame = ff_null_start_frame_keep_ref, .end_frame = end_frame, }, { .name = NULL } }, .outputs = (const AVFilterPad[]) { { .name = "default", .type = AVMEDIA_TYPE_VIDEO, .request_frame = request_frame, }, { .name = NULL } }, };