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Diffstat (limited to 'libavfilter/vf_blackdetect.c')
-rw-r--r-- | libavfilter/vf_blackdetect.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/libavfilter/vf_blackdetect.c b/libavfilter/vf_blackdetect.c new file mode 100644 index 0000000..87a7a23 --- /dev/null +++ b/libavfilter/vf_blackdetect.c @@ -0,0 +1,209 @@ +/* + * 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 <float.h> +#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 nb_black_pixels; ///< number of black pixels counted so far +} BlackDetectContext; + +#define OFFSET(x) offsetof(BlackDetectContext, x) +#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM + +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, FLAGS }, + { "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 }, + { "picture_black_ratio_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS }, + { "pic_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS }, + { "pixel_black_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS }, + { "pix_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS }, + { NULL } +}; + +AVFILTER_DEFINE_CLASS(blackdetect); + +#define YUVJ_FORMATS \ + AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P + +static const enum AVPixelFormat yuvj_formats[] = { + YUVJ_FORMATS, AV_PIX_FMT_NONE +}; + +static int query_formats(AVFilterContext *ctx) +{ + static const enum AVPixelFormat pix_fmts[] = { + AV_PIX_FMT_GRAY8, + AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P, + AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, + AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P, + AV_PIX_FMT_NV12, AV_PIX_FMT_NV21, + YUVJ_FORMATS, + AV_PIX_FMT_NONE + }; + + ff_set_common_formats(ctx, ff_make_format_list(pix_fmts)); + 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_VERBOSE, + "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 = ff_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; +} + +// TODO: document metadata +static int filter_frame(AVFilterLink *inlink, AVFrame *picref) +{ + AVFilterContext *ctx = inlink->dst; + BlackDetectContext *blackdetect = ctx->priv; + double picture_black_ratio = 0; + const uint8_t *p = picref->data[0]; + int x, i; + + for (i = 0; i < inlink->h; i++) { + for (x = 0; x < inlink->w; x++) + blackdetect->nb_black_pixels += p[x] <= blackdetect->pixel_black_th_i; + p += picref->linesize[0]; + } + + picture_black_ratio = (double)blackdetect->nb_black_pixels / (inlink->w * inlink->h); + + av_log(ctx, AV_LOG_DEBUG, + "frame:%"PRId64" picture_black_ratio:%f pts:%s t:%s type:%c\n", + inlink->frame_count, picture_black_ratio, + av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base), + av_get_picture_type_char(picref->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; + av_dict_set(avpriv_frame_get_metadatap(picref), "lavfi.black_start", + av_ts2timestr(blackdetect->black_start, &inlink->time_base), 0); + } + } else if (blackdetect->black_started) { + /* black ends here */ + blackdetect->black_started = 0; + blackdetect->black_end = picref->pts; + check_black_end(ctx); + av_dict_set(avpriv_frame_get_metadatap(picref), "lavfi.black_end", + av_ts2timestr(blackdetect->black_end, &inlink->time_base), 0); + } + + blackdetect->last_picref_pts = picref->pts; + blackdetect->nb_black_pixels = 0; + return ff_filter_frame(inlink->dst->outputs[0], picref); +} + +static const AVFilterPad blackdetect_inputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_VIDEO, + .config_props = config_input, + .filter_frame = filter_frame, + }, + { NULL } +}; + +static const AVFilterPad blackdetect_outputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_VIDEO, + .request_frame = request_frame, + }, + { NULL } +}; + +AVFilter ff_vf_blackdetect = { + .name = "blackdetect", + .description = NULL_IF_CONFIG_SMALL("Detect video intervals that are (almost) black."), + .priv_size = sizeof(BlackDetectContext), + .query_formats = query_formats, + .inputs = blackdetect_inputs, + .outputs = blackdetect_outputs, + .priv_class = &blackdetect_class, +}; |