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vf_blackdetect.c
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1 /*
2  * Copyright (c) 2012 Stefano Sabatini
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * Video black detector, loosely based on blackframe with extended
24  * syntax and features
25  */
26 
27 #include <float.h>
28 #include "libavutil/opt.h"
29 #include "libavutil/timestamp.h"
30 #include "avfilter.h"
31 #include "internal.h"
32 
33 typedef struct {
34  const AVClass *class;
35  double black_min_duration_time; ///< minimum duration of detected black, in seconds
36  int64_t black_min_duration; ///< minimum duration of detected black, expressed in timebase units
37  int64_t black_start; ///< pts start time of the first black picture
38  int64_t black_end; ///< pts end time of the last black picture
39  int64_t last_picref_pts; ///< pts of the last input picture
41 
44  unsigned int pixel_black_th_i;
45 
46  unsigned int nb_black_pixels; ///< number of black pixels counted so far
48 
49 #define OFFSET(x) offsetof(BlackDetectContext, x)
50 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
51 
52 static const AVOption blackdetect_options[] = {
53  { "d", "set minimum detected black duration in seconds", OFFSET(black_min_duration_time), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, DBL_MAX, FLAGS },
54  { "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 },
55  { "picture_black_ratio_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS },
56  { "pic_th", "set the picture black ratio threshold", OFFSET(picture_black_ratio_th), AV_OPT_TYPE_DOUBLE, {.dbl=.98}, 0, 1, FLAGS },
57  { "pixel_black_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS },
58  { "pix_th", "set the pixel black threshold", OFFSET(pixel_black_th), AV_OPT_TYPE_DOUBLE, {.dbl=.10}, 0, 1, FLAGS },
59  { NULL }
60 };
61 
62 AVFILTER_DEFINE_CLASS(blackdetect);
63 
64 #define YUVJ_FORMATS \
65  AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P
66 
67 static const enum AVPixelFormat yuvj_formats[] = {
69 };
70 
72 {
73  static const enum AVPixelFormat pix_fmts[] = {
81  };
82 
84  return 0;
85 }
86 
87 static int config_input(AVFilterLink *inlink)
88 {
89  AVFilterContext *ctx = inlink->dst;
90  BlackDetectContext *blackdetect = ctx->priv;
91 
92  blackdetect->black_min_duration =
93  blackdetect->black_min_duration_time / av_q2d(inlink->time_base);
94 
95  blackdetect->pixel_black_th_i = ff_fmt_is_in(inlink->format, yuvj_formats) ?
96  // luminance_minimum_value + pixel_black_th * luminance_range_size
97  blackdetect->pixel_black_th * 255 :
98  16 + blackdetect->pixel_black_th * (235 - 16);
99 
100  av_log(blackdetect, AV_LOG_VERBOSE,
101  "black_min_duration:%s pixel_black_th:%f pixel_black_th_i:%d picture_black_ratio_th:%f\n",
102  av_ts2timestr(blackdetect->black_min_duration, &inlink->time_base),
103  blackdetect->pixel_black_th, blackdetect->pixel_black_th_i,
104  blackdetect->picture_black_ratio_th);
105  return 0;
106 }
107 
109 {
110  BlackDetectContext *blackdetect = ctx->priv;
111  AVFilterLink *inlink = ctx->inputs[0];
112 
113  if ((blackdetect->black_end - blackdetect->black_start) >= blackdetect->black_min_duration) {
114  av_log(blackdetect, AV_LOG_INFO,
115  "black_start:%s black_end:%s black_duration:%s\n",
116  av_ts2timestr(blackdetect->black_start, &inlink->time_base),
117  av_ts2timestr(blackdetect->black_end, &inlink->time_base),
118  av_ts2timestr(blackdetect->black_end - blackdetect->black_start, &inlink->time_base));
119  }
120 }
121 
122 static int request_frame(AVFilterLink *outlink)
123 {
124  AVFilterContext *ctx = outlink->src;
125  BlackDetectContext *blackdetect = ctx->priv;
126  AVFilterLink *inlink = ctx->inputs[0];
127  int ret = ff_request_frame(inlink);
128 
129  if (ret == AVERROR_EOF && blackdetect->black_started) {
130  // FIXME: black_end should be set to last_picref_pts + last_picref_duration
131  blackdetect->black_end = blackdetect->last_picref_pts;
132  check_black_end(ctx);
133  }
134  return ret;
135 }
136 
137 // TODO: document metadata
138 static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
139 {
140  AVFilterContext *ctx = inlink->dst;
141  BlackDetectContext *blackdetect = ctx->priv;
142  double picture_black_ratio = 0;
143  const uint8_t *p = picref->data[0];
144  int x, i;
145 
146  for (i = 0; i < inlink->h; i++) {
147  for (x = 0; x < inlink->w; x++)
148  blackdetect->nb_black_pixels += p[x] <= blackdetect->pixel_black_th_i;
149  p += picref->linesize[0];
150  }
151 
152  picture_black_ratio = (double)blackdetect->nb_black_pixels / (inlink->w * inlink->h);
153 
154  av_log(ctx, AV_LOG_DEBUG,
155  "frame:%"PRId64" picture_black_ratio:%f pts:%s t:%s type:%c\n",
156  inlink->frame_count, picture_black_ratio,
157  av_ts2str(picref->pts), av_ts2timestr(picref->pts, &inlink->time_base),
159 
160  if (picture_black_ratio >= blackdetect->picture_black_ratio_th) {
161  if (!blackdetect->black_started) {
162  /* black starts here */
163  blackdetect->black_started = 1;
164  blackdetect->black_start = picref->pts;
165  av_dict_set(avpriv_frame_get_metadatap(picref), "lavfi.black_start",
166  av_ts2timestr(blackdetect->black_start, &inlink->time_base), 0);
167  }
168  } else if (blackdetect->black_started) {
169  /* black ends here */
170  blackdetect->black_started = 0;
171  blackdetect->black_end = picref->pts;
172  check_black_end(ctx);
173  av_dict_set(avpriv_frame_get_metadatap(picref), "lavfi.black_end",
174  av_ts2timestr(blackdetect->black_end, &inlink->time_base), 0);
175  }
176 
177  blackdetect->last_picref_pts = picref->pts;
178  blackdetect->nb_black_pixels = 0;
179  return ff_filter_frame(inlink->dst->outputs[0], picref);
180 }
181 
182 static const AVFilterPad blackdetect_inputs[] = {
183  {
184  .name = "default",
185  .type = AVMEDIA_TYPE_VIDEO,
186  .config_props = config_input,
187  .filter_frame = filter_frame,
188  },
189  { NULL }
190 };
191 
193  {
194  .name = "default",
195  .type = AVMEDIA_TYPE_VIDEO,
196  .request_frame = request_frame,
197  },
198  { NULL }
199 };
200 
202  .name = "blackdetect",
203  .description = NULL_IF_CONFIG_SMALL("Detect video intervals that are (almost) black."),
204  .priv_size = sizeof(BlackDetectContext),
206  .inputs = blackdetect_inputs,
207  .outputs = blackdetect_outputs,
208  .priv_class = &blackdetect_class,
209 };
#define NULL
Definition: coverity.c:32
This structure describes decoded (raw) audio or video data.
Definition: frame.h:163
AVOption.
Definition: opt.h:255
planar YUV 4:4:4, 24bpp, (1 Cr & Cb sample per 1x1 Y samples)
Definition: pixfmt.h:73
static const AVFilterPad outputs[]
Definition: af_ashowinfo.c:246
Main libavfilter public API header.
AVFilter ff_vf_blackdetect
AVFilterFormats * ff_make_format_list(const int *fmts)
Create a list of supported formats.
Definition: formats.c:294
unsigned int nb_black_pixels
number of black pixels counted so far
const char * name
Pad name.
Definition: internal.h:67
AVFilterLink ** inputs
array of pointers to input links
Definition: avfilter.h:641
static const AVFilterPad blackdetect_inputs[]
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1145
uint8_t
AVOptions.
static int config_input(AVFilterLink *inlink)
timestamp utils, mostly useful for debugging/logging purposes
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition: frame.h:249
static int query_formats(AVFilterContext *ctx)
static double av_q2d(AVRational a)
Convert rational to double.
Definition: rational.h:80
char av_get_picture_type_char(enum AVPictureType pict_type)
Return a single letter to describe the given picture type pict_type.
Definition: utils.c:84
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:191
void ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
A helper for query_formats() which sets all links to the same list of formats.
Definition: formats.c:539
int ff_fmt_is_in(int fmt, const int *fmts)
Tell is a format is contained in the provided list terminated by -1.
Definition: formats.c:254
#define av_log(a,...)
int64_t black_min_duration
minimum duration of detected black, expressed in timebase units
double picture_black_ratio_th
A filter pad used for either input or output.
Definition: internal.h:61
#define av_ts2timestr(ts, tb)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: timestamp.h:76
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:180
void * priv
private data for use by the filter
Definition: avfilter.h:654
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:196
planar YUV 4:2:0, 12bpp, 1 plane for Y and 1 plane for the UV components, which are interleaved (firs...
Definition: pixfmt.h:96
#define OFFSET(x)
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:72
static const AVFilterPad blackdetect_outputs[]
as above, but U and V bytes are swapped
Definition: pixfmt.h:97
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:234
double black_min_duration_time
minimum duration of detected black, in seconds
int64_t last_picref_pts
pts of the last input picture
ret
Definition: avfilter.c:974
#define FLAGS
unsigned int pixel_black_th_i
AVFILTER_DEFINE_CLASS(blackdetect)
static void check_black_end(AVFilterContext *ctx)
#define AV_LOG_INFO
Standard information.
Definition: log.h:186
static enum AVPixelFormat yuvj_formats[]
AVDictionary ** avpriv_frame_get_metadatap(AVFrame *frame)
Definition: frame.c:47
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:191
#define YUVJ_FORMATS
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:69
planar YUV 4:1:0, 9bpp, (1 Cr & Cb sample per 4x4 Y samples)
Definition: pixfmt.h:74
int64_t black_end
pts end time of the last black picture
Describe the class of an AVClass context structure.
Definition: log.h:66
Filter definition.
Definition: avfilter.h:470
static const AVFilterPad inputs[]
Definition: af_ashowinfo.c:237
const char * name
Filter name.
Definition: avfilter.h:474
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:648
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:174
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:68
Y , 8bpp.
Definition: pixfmt.h:76
planar YUV 4:1:1, 12bpp, (1 Cr & Cb sample per 4x1 Y samples)
Definition: pixfmt.h:75
int64_t black_start
pts start time of the first black picture
#define av_ts2str(ts)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: timestamp.h:54
An instance of a filter.
Definition: avfilter.h:633
planar YUV 4:4:0 (1 Cr & Cb sample per 1x2 Y samples)
Definition: pixfmt.h:106
static int request_frame(AVFilterLink *outlink)
int ff_request_frame(AVFilterLink *link)
Request an input frame from the filter at the other end of the link.
Definition: avfilter.c:343
static const AVOption blackdetect_options[]
internal API functions
AVPixelFormat
Pixel format.
Definition: pixfmt.h:66
static int filter_frame(AVFilterLink *inlink, AVFrame *picref)