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 Libav.
9 * Libav 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 * Libav 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 Libav; 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 unsigned int bamount; ///< black amount
34 unsigned int bthresh; ///< black threshold
35 unsigned int frame; ///< frame number
36 unsigned int nblack; ///< number of black pixels counted so far
39 static int query_formats(AVFilterContext *ctx)
41 static const enum PixelFormat pix_fmts[] = {
42 PIX_FMT_YUV410P, PIX_FMT_YUV420P, PIX_FMT_GRAY8, PIX_FMT_NV12,
43 PIX_FMT_NV21, PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV411P,
47 avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
51 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
53 BlackFrameContext *blackframe = ctx->priv;
55 blackframe->bamount = 98;
56 blackframe->bthresh = 32;
57 blackframe->nblack = 0;
58 blackframe->frame = 0;
61 sscanf(args, "%u:%u", &blackframe->bamount, &blackframe->bthresh);
63 av_log(ctx, AV_LOG_INFO, "bamount:%u bthresh:%u\n",
64 blackframe->bamount, blackframe->bthresh);
66 if (blackframe->bamount > 100 || blackframe->bthresh > 255) {
67 av_log(ctx, AV_LOG_ERROR, "Too big value for bamount (max is 100) or bthresh (max is 255)\n");
68 return AVERROR(EINVAL);
74 static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
76 AVFilterContext *ctx = inlink->dst;
77 BlackFrameContext *blackframe = ctx->priv;
78 AVFilterBufferRef *picref = inlink->cur_buf;
80 uint8_t *p = picref->data[0] + y * picref->linesize[0];
82 for (i = 0; i < h; i++) {
83 for (x = 0; x < inlink->w; x++)
84 blackframe->nblack += p[x] < blackframe->bthresh;
85 p += picref->linesize[0];
88 avfilter_draw_slice(ctx->outputs[0], y, h, slice_dir);
91 static void end_frame(AVFilterLink *inlink)
93 AVFilterContext *ctx = inlink->dst;
94 BlackFrameContext *blackframe = ctx->priv;
95 AVFilterBufferRef *picref = inlink->cur_buf;
98 pblack = blackframe->nblack * 100 / (inlink->w * inlink->h);
99 if (pblack >= blackframe->bamount)
100 av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pos:%"PRId64" pts:%"PRId64" t:%f\n",
101 blackframe->frame, pblack, picref->pos, picref->pts,
102 picref->pts == AV_NOPTS_VALUE ? -1 : picref->pts * av_q2d(inlink->time_base));
105 blackframe->nblack = 0;
106 avfilter_end_frame(inlink->dst->outputs[0]);
109 AVFilter avfilter_vf_blackframe = {
110 .name = "blackframe",
111 .description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
113 .priv_size = sizeof(BlackFrameContext),
116 .query_formats = query_formats,
118 .inputs = (AVFilterPad[]) {{ .name = "default",
119 .type = AVMEDIA_TYPE_VIDEO,
120 .draw_slice = draw_slice,
121 .get_video_buffer = avfilter_null_get_video_buffer,
122 .start_frame = avfilter_null_start_frame,
123 .end_frame = end_frame, },
126 .outputs = (AVFilterPad[]) {{ .name = "default",
127 .type = AVMEDIA_TYPE_VIDEO },