yading@10: /*
yading@10:  * Copyright (c) 2012 Stefano Sabatini
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Video black detector, loosely based on blackframe with extended
yading@10:  * syntax and features
yading@10:  */
yading@10: 
yading@10: #include <float.h>
yading@10: #include "libavutil/opt.h"
yading@10: #include "libavutil/timestamp.h"
yading@10: #include "avfilter.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: typedef struct {
yading@10:     const AVClass *class;
yading@10:     double  black_min_duration_time; ///< minimum duration of detected black, in seconds
yading@10:     int64_t black_min_duration;      ///< minimum duration of detected black, expressed in timebase units
yading@10:     int64_t black_start;             ///< pts start time of the first black picture
yading@10:     int64_t black_end;               ///< pts end time of the last black picture
yading@10:     int64_t last_picref_pts;         ///< pts of the last input picture
yading@10:     int black_started;
yading@10: 
yading@10:     double       picture_black_ratio_th;
yading@10:     double       pixel_black_th;
yading@10:     unsigned int pixel_black_th_i;
yading@10: 
yading@10:     unsigned int frame_count;       ///< frame number
yading@10:     unsigned int nb_black_pixels;   ///< number of black pixels counted so far
yading@10: } BlackDetectContext;
yading@10: 
yading@10: #define OFFSET(x) offsetof(BlackDetectContext, x)
yading@10: #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
yading@10: 
yading@10: static const AVOption blackdetect_options[] = {
yading@10:     { "d",                  "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX, FLAGS },
yading@10:     { "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 },
yading@10:     { "picture_black_ratio_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS },
yading@10:     { "pic_th",                 "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS },
yading@10:     { "pixel_black_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS },
yading@10:     { "pix_th",         "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS },
yading@10:     { NULL },
yading@10: };
yading@10: 
yading@10: AVFILTER_DEFINE_CLASS(blackdetect);
yading@10: 
yading@10: #define YUVJ_FORMATS \
yading@10:     AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P
yading@10: 
yading@10: static enum AVPixelFormat yuvj_formats[] = {
yading@10:     YUVJ_FORMATS, AV_PIX_FMT_NONE
yading@10: };
yading@10: 
yading@10: static int query_formats(AVFilterContext *ctx)
yading@10: {
yading@10:     static const enum AVPixelFormat pix_fmts[] = {
yading@10:         AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NV12,
yading@10:         AV_PIX_FMT_NV21, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
yading@10:         YUVJ_FORMATS,
yading@10:         AV_PIX_FMT_NONE
yading@10:     };
yading@10: 
yading@10:     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int config_input(AVFilterLink *inlink)
yading@10: {
yading@10:     AVFilterContext *ctx = inlink->dst;
yading@10:     BlackDetectContext *blackdetect = ctx->priv;
yading@10: 
yading@10:     blackdetect->black_min_duration =
yading@10:         blackdetect->black_min_duration_time / av_q2d(inlink->time_base);
yading@10: 
yading@10:     blackdetect->pixel_black_th_i = ff_fmt_is_in(inlink->format, yuvj_formats) ?
yading@10:         // luminance_minimum_value + pixel_black_th * luminance_range_size
yading@10:              blackdetect->pixel_black_th *  255 :
yading@10:         16 + blackdetect->pixel_black_th * (235 - 16);
yading@10: 
yading@10:     av_log(blackdetect, AV_LOG_VERBOSE,
yading@10:            "black_min_duration:%s pixel_black_th:%f pixel_black_th_i:%d picture_black_ratio_th:%f\n",
yading@10:            av_ts2timestr(blackdetect->black_min_duration, &inlink->time_base),
yading@10:            blackdetect->pixel_black_th, blackdetect->pixel_black_th_i,
yading@10:            blackdetect->picture_black_ratio_th);
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static void check_black_end(AVFilterContext *ctx)
yading@10: {
yading@10:     BlackDetectContext *blackdetect = ctx->priv;
yading@10:     AVFilterLink *inlink = ctx->inputs[0];
yading@10: 
yading@10:     if ((blackdetect->black_end - blackdetect->black_start) >= blackdetect->black_min_duration) {
yading@10:         av_log(blackdetect, AV_LOG_INFO,
yading@10:                "black_start:%s black_end:%s black_duration:%s\n",
yading@10:                av_ts2timestr(blackdetect->black_start, &inlink->time_base),
yading@10:                av_ts2timestr(blackdetect->black_end,   &inlink->time_base),
yading@10:                av_ts2timestr(blackdetect->black_end - blackdetect->black_start, &inlink->time_base));
yading@10:     }
yading@10: }
yading@10: 
yading@10: static int request_frame(AVFilterLink *outlink)
yading@10: {
yading@10:     AVFilterContext *ctx = outlink->src;
yading@10:     BlackDetectContext *blackdetect = ctx->priv;
yading@10:     AVFilterLink *inlink = ctx->inputs[0];
yading@10:     int ret = ff_request_frame(inlink);
yading@10: 
yading@10:     if (ret == AVERROR_EOF && blackdetect->black_started) {
yading@10:         // FIXME: black_end should be set to last_picref_pts + last_picref_duration
yading@10:         blackdetect->black_end = blackdetect->last_picref_pts;
yading@10:         check_black_end(ctx);
yading@10:     }
yading@10:     return ret;
yading@10: }
yading@10: 
yading@10: static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
yading@10: {
yading@10:     AVFilterContext *ctx = inlink->dst;
yading@10:     BlackDetectContext *blackdetect = ctx->priv;
yading@10:     double picture_black_ratio = 0;
yading@10:     const uint8_t *p = picref->data[0];
yading@10:     int x, i;
yading@10: 
yading@10:     for (i = 0; i < inlink->h; i++) {
yading@10:         for (x = 0; x < inlink->w; x++)
yading@10:             blackdetect->nb_black_pixels += p[x] <= blackdetect->pixel_black_th_i;
yading@10:         p += picref->linesize[0];
yading@10:     }
yading@10: 
yading@10:     picture_black_ratio = (double)blackdetect->nb_black_pixels / (inlink->w * inlink->h);
yading@10: 
yading@10:     av_log(ctx, AV_LOG_DEBUG,
yading@10:            "frame:%u picture_black_ratio:%f pts:%s t:%s type:%c\n",
yading@10:            blackdetect->frame_count, picture_black_ratio,
yading@10:            av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base),
yading@10:            av_get_picture_type_char(picref->pict_type));
yading@10: 
yading@10:     if (picture_black_ratio >= blackdetect->picture_black_ratio_th) {
yading@10:         if (!blackdetect->black_started) {
yading@10:             /* black starts here */
yading@10:             blackdetect->black_started = 1;
yading@10:             blackdetect->black_start = picref->pts;
yading@10:         }
yading@10:     } else if (blackdetect->black_started) {
yading@10:         /* black ends here */
yading@10:         blackdetect->black_started = 0;
yading@10:         blackdetect->black_end = picref->pts;
yading@10:         check_black_end(ctx);
yading@10:     }
yading@10: 
yading@10:     blackdetect->last_picref_pts = picref->pts;
yading@10:     blackdetect->frame_count++;
yading@10:     blackdetect->nb_black_pixels = 0;
yading@10:     return ff_filter_frame(inlink->dst->outputs[0], picref);
yading@10: }
yading@10: 
yading@10: static const AVFilterPad blackdetect_inputs[] = {
yading@10:     {
yading@10:         .name             = "default",
yading@10:         .type             = AVMEDIA_TYPE_VIDEO,
yading@10:         .config_props     = config_input,
yading@10:         .get_video_buffer = ff_null_get_video_buffer,
yading@10:         .filter_frame     = filter_frame,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: static const AVFilterPad blackdetect_outputs[] = {
yading@10:     {
yading@10:         .name          = "default",
yading@10:         .type          = AVMEDIA_TYPE_VIDEO,
yading@10:         .request_frame = request_frame,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: AVFilter avfilter_vf_blackdetect = {
yading@10:     .name          = "blackdetect",
yading@10:     .description   = NULL_IF_CONFIG_SMALL("Detect video intervals that are (almost) black."),
yading@10:     .priv_size     = sizeof(BlackDetectContext),
yading@10:     .query_formats = query_formats,
yading@10:     .inputs        = blackdetect_inputs,
yading@10:     .outputs       = blackdetect_outputs,
yading@10:     .priv_class    = &blackdetect_class,
yading@10: };