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vf_blackframe.c
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1 /*
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
6  *
7  * This file is part of FFmpeg.
8  *
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.
13  *
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.
18  *
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.
22  */
23 
24 /**
25  * @file
26  * Search for black frames to detect scene transitions.
27  * Ported from MPlayer libmpcodecs/vf_blackframe.c.
28  */
29 
30 #include <stdio.h>
31 #include <inttypes.h>
32 
33 #include "libavutil/internal.h"
34 #include "libavutil/opt.h"
35 #include "avfilter.h"
36 #include "formats.h"
37 #include "internal.h"
38 #include "video.h"
39 
40 typedef struct BlackFrameContext {
41  const AVClass *class;
42  int bamount; ///< black amount
43  int bthresh; ///< black threshold
44  unsigned int frame; ///< frame number
45  unsigned int nblack; ///< number of black pixels counted so far
46  unsigned int last_keyframe; ///< frame number of the last received key-frame
48 
50 {
51  static const enum AVPixelFormat pix_fmts[] = {
55  };
56 
57  AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
58  if (!fmts_list)
59  return AVERROR(ENOMEM);
60  return ff_set_common_formats(ctx, fmts_list);
61 }
62 
63 #define SET_META(key, format, value) \
64  snprintf(buf, sizeof(buf), format, value); \
65  av_dict_set(metadata, key, buf, 0)
66 
67 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
68 {
69  AVFilterContext *ctx = inlink->dst;
70  BlackFrameContext *s = ctx->priv;
71  int x, i;
72  int pblack = 0;
73  uint8_t *p = frame->data[0];
74  AVDictionary **metadata;
75  char buf[32];
76 
77  for (i = 0; i < frame->height; i++) {
78  for (x = 0; x < inlink->w; x++)
79  s->nblack += p[x] < s->bthresh;
80  p += frame->linesize[0];
81  }
82 
83  if (frame->key_frame)
84  s->last_keyframe = s->frame;
85 
86  pblack = s->nblack * 100 / (inlink->w * inlink->h);
87  if (pblack >= s->bamount) {
88  metadata = avpriv_frame_get_metadatap(frame);
89 
90  av_log(ctx, AV_LOG_INFO, "frame:%u pblack:%u pts:%"PRId64" t:%f "
91  "type:%c last_keyframe:%d\n",
92  s->frame, pblack, frame->pts,
93  frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base),
95 
96  SET_META("lavfi.blackframe.pblack", "%u", pblack);
97  }
98 
99  s->frame++;
100  s->nblack = 0;
101  return ff_filter_frame(inlink->dst->outputs[0], frame);
102 }
103 
104 #define OFFSET(x) offsetof(BlackFrameContext, x)
105 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
106 static const AVOption blackframe_options[] = {
107  { "amount", "Percentage of the pixels that have to be below the threshold "
108  "for the frame to be considered black.", OFFSET(bamount), AV_OPT_TYPE_INT, { .i64 = 98 }, 0, 100, FLAGS },
109  { "threshold", "threshold below which a pixel value is considered black",
110  OFFSET(bthresh), AV_OPT_TYPE_INT, { .i64 = 32 }, 0, 255, FLAGS },
111  { "thresh", "threshold below which a pixel value is considered black",
112  OFFSET(bthresh), AV_OPT_TYPE_INT, { .i64 = 32 }, 0, 255, FLAGS },
113  { NULL }
114 };
115 
116 AVFILTER_DEFINE_CLASS(blackframe);
117 
119  {
120  .name = "default",
121  .type = AVMEDIA_TYPE_VIDEO,
122  .filter_frame = filter_frame,
123  },
124  { NULL }
125 };
126 
128  {
129  .name = "default",
130  .type = AVMEDIA_TYPE_VIDEO
131  },
132  { NULL }
133 };
134 
136  .name = "blackframe",
137  .description = NULL_IF_CONFIG_SMALL("Detect frames that are (almost) black."),
138  .priv_size = sizeof(BlackFrameContext),
139  .priv_class = &blackframe_class,
141  .inputs = avfilter_vf_blackframe_inputs,
142  .outputs = avfilter_vf_blackframe_outputs,
143 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
static const AVOption blackframe_options[]
This structure describes decoded (raw) audio or video data.
Definition: frame.h:184
AVOption.
Definition: opt.h:245
planar YUV 4:4:4, 24bpp, (1 Cr & Cb sample per 1x1 Y samples)
Definition: pixfmt.h:67
unsigned int last_keyframe
frame number of the last received key-frame
Definition: vf_blackframe.c:46
Main libavfilter public API header.
static const AVFilterPad avfilter_vf_blackframe_inputs[]
AVFilterFormats * ff_make_format_list(const int *fmts)
Create a list of supported formats.
Definition: formats.c:283
const char * name
Pad name.
Definition: internal.h:59
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1180
uint8_t
AVOptions.
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition: frame.h:268
static AVFrame * frame
static double av_q2d(AVRational a)
Convert an AVRational to a double.
Definition: rational.h:104
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:91
#define av_log(a,...)
A filter pad used for either input or output.
Definition: internal.h:53
#define SET_META(key, format, value)
Definition: vf_blackframe.c:63
int 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:568
#define AVERROR(e)
Definition: error.h:43
int bamount
black amount
Definition: vf_blackframe.c:42
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
void * priv
private data for use by the filter
Definition: avfilter.h:322
planar YUV 4:2:0, 12bpp, 1 plane for Y and 1 plane for the UV components, which are interleaved (firs...
Definition: pixfmt.h:90
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:66
common internal API header
as above, but U and V bytes are swapped
Definition: pixfmt.h:91
#define FLAGS
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:258
AVFilter ff_vf_blackframe
AVFormatContext * ctx
Definition: movenc.c:48
unsigned int frame
frame number
Definition: vf_blackframe.c:44
#define OFFSET(x)
static const AVFilterPad outputs[]
Definition: af_afftfilt.c:386
unsigned int nblack
number of black pixels counted so far
Definition: vf_blackframe.c:45
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
static const AVFilterPad inputs[]
Definition: af_afftfilt.c:376
AVFILTER_DEFINE_CLASS(blackframe)
AVDictionary ** avpriv_frame_get_metadatap(AVFrame *frame)
Definition: frame.c:46
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:215
void * buf
Definition: avisynth_c.h:690
int bthresh
black threshold
Definition: vf_blackframe.c:43
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
Definition: vf_blackframe.c:67
planar YUV 4:1:0, 9bpp, (1 Cr & Cb sample per 4x4 Y samples)
Definition: pixfmt.h:68
Describe the class of an AVClass context structure.
Definition: log.h:67
Filter definition.
Definition: avfilter.h:144
const char * name
Filter name.
Definition: avfilter.h:148
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:319
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:262
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:198
static const AVFilterPad avfilter_vf_blackframe_outputs[]
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:62
Y , 8bpp.
Definition: pixfmt.h:70
planar YUV 4:1:1, 12bpp, (1 Cr & Cb sample per 4x1 Y samples)
Definition: pixfmt.h:69
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:253
A list of supported formats for one end of a filter link.
Definition: formats.h:64
An instance of a filter.
Definition: avfilter.h:307
int height
Definition: frame.h:236
internal API functions
AVPixelFormat
Pixel format.
Definition: pixfmt.h:60
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:242
static int query_formats(AVFilterContext *ctx)
Definition: vf_blackframe.c:49