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-rw-r--r--libavfilter/vf_blackdetect.c225
1 files changed, 225 insertions, 0 deletions
diff --git a/libavfilter/vf_blackdetect.c b/libavfilter/vf_blackdetect.c
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+++ b/libavfilter/vf_blackdetect.c
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+/*
+ * 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 frame_count; ///< frame number
+ 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_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P
+
+static 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_YUV410P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NV12,
+ AV_PIX_FMT_NV21, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
+ YUVJ_FORMATS,
+ AV_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)
+{
+ int ret;
+ BlackDetectContext *blackdetect = ctx->priv;
+
+ blackdetect->class = &blackdetect_class;
+ av_opt_set_defaults(blackdetect);
+
+ if ((ret = av_set_options_string(blackdetect, args, "=", ":")) < 0)
+ 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_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;
+}
+
+static int 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];
+ }
+
+ return ff_draw_slice(ctx->outputs[0], y, h, slice_dir);
+}
+
+static int 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;
+ return 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,
+ .end_frame = end_frame, },
+ { .name = NULL }
+ },
+
+ .outputs = (const AVFilterPad[]) {
+ { .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .request_frame = request_frame, },
+ { .name = NULL }
+ },
+ .priv_class = &blackdetect_class,
+};
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-11 02:26:26 +0000