2 * Copyright (c) 2010 Stefano Sabatini
3 * Copyright (c) 2006 Ivo van Poorten
4 * Copyright (c) 2006 Julian Hall
5 * Copyright (c) 2002-2003 Brian J. Murrell
7 * This file is part of FFmpeg.
9 * FFmpeg is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License along
20 * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
26 * Search for black frames to detect scene transitions.
27 * Ported from MPlayer libmpcodecs/vf_blackframe.c.
33 #include "libavutil/internal.h"
41 unsigned int bamount; ///< black amount
42 unsigned int bthresh; ///< black threshold
43 unsigned int frame; ///< frame number
44 unsigned int nblack; ///< number of black pixels counted so far
45 unsigned int last_keyframe; ///< frame number of the last received key-frame
48 static int query_formats(AVFilterContext *ctx)
50 static const enum AVPixelFormat pix_fmts[] = {
51 AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NV12,
52 AV_PIX_FMT_NV21, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
56 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
60 static av_cold int init(AVFilterContext *ctx, const char *args)
62 BlackFrameContext *blackframe = ctx->priv;
64 blackframe->bamount = 98;
65 blackframe->bthresh = 32;
66 blackframe->nblack = 0;
67 blackframe->frame = 0;
68 blackframe->last_keyframe = 0;
71 sscanf(args, "%u:%u", &blackframe->bamount, &blackframe->bthresh);
73 av_log(ctx, AV_LOG_VERBOSE, "bamount:%u bthresh:%u\n",
74 blackframe->bamount, blackframe->bthresh);
76 if (blackframe->bamount > 100 || blackframe->bthresh > 255) {
77 av_log(ctx, AV_LOG_ERROR, "Too big value for bamount (max is 100) or bthresh (max is 255)\n");
78 return AVERROR(EINVAL);
84 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *frame)
86 AVFilterContext *ctx = inlink->dst;
87 BlackFrameContext *blackframe = ctx->priv;
90 uint8_t *p = frame->data[0];
92 for (i = 0; i < frame->video->h; i++) {
93 for (x = 0; x < inlink->w; x++)
94 blackframe->nblack += p[x] < blackframe->bthresh;
95 p += frame->linesize[0];
98 if (frame->video->key_frame)
99 blackframe->last_keyframe = blackframe->frame;
101 pblack = blackframe->nblack * 100 / (inlink->w * inlink->h);
102 if (pblack >= blackframe->bamount)
103 av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pos:%"PRId64" pts:%"PRId64" t:%f "
104 "type:%c last_keyframe:%d\n",
105 blackframe->frame, pblack, frame->pos, frame->pts,
106 frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base),
107 av_get_picture_type_char(frame->video->pict_type), blackframe->last_keyframe);
110 blackframe->nblack = 0;
111 return ff_filter_frame(inlink->dst->outputs[0], frame);
114 static const AVFilterPad avfilter_vf_blackframe_inputs[] = {
117 .type = AVMEDIA_TYPE_VIDEO,
118 .get_video_buffer = ff_null_get_video_buffer,
119 .filter_frame = filter_frame,
124 static const AVFilterPad avfilter_vf_blackframe_outputs[] = {
127 .type = AVMEDIA_TYPE_VIDEO
132 AVFilter avfilter_vf_blackframe = {
133 .name = "blackframe",
134 .description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
136 .priv_size = sizeof(BlackFrameContext),
139 .query_formats = query_formats,
141 .inputs = avfilter_vf_blackframe_inputs,
143 .outputs = avfilter_vf_blackframe_outputs,