FFmpeg
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 
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 = &frame->metadata;
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
static const AVOption blackframe_options[]
This structure describes decoded (raw) audio or video data.
Definition: frame.h:295
AVOption.
Definition: opt.h:246
planar YUV 4:4:4, 24bpp, (1 Cr & Cb sample per 1x1 Y samples)
Definition: pixfmt.h:71
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:60
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1080
uint8_t
AVOptions.
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition: frame.h:388
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:88
AVDictionary * metadata
metadata.
Definition: frame.h:581
#define av_log(a,...)
A filter pad used for either input or output.
Definition: internal.h:54
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#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
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:186
void * priv
private data for use by the filter
Definition: avfilter.h:353
planar YUV 4:2:0, 12bpp, 1 plane for Y and 1 plane for the UV components, which are interleaved (firs...
Definition: pixfmt.h:89
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:70
common internal API header
as above, but U and V bytes are swapped
Definition: pixfmt.h:90
#define FLAGS
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:378
AVFilter ff_vf_blackframe
AVFormatContext * ctx
Definition: movenc.c:48
#define s(width, name)
Definition: cbs_vp9.c:257
unsigned int frame
frame number
Definition: vf_blackframe.c:44
#define OFFSET(x)
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
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
AVFILTER_DEFINE_CLASS(blackframe)
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:326
void * buf
Definition: avisynth_c.h:766
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several inputs
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:72
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:350
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:275
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is inlink
static const AVFilterPad avfilter_vf_blackframe_outputs[]
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:66
Y , 8bpp.
Definition: pixfmt.h:74
planar YUV 4:1:1, 12bpp, (1 Cr & Cb sample per 4x1 Y samples)
Definition: pixfmt.h:73
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:373
A list of supported formats for one end of a filter link.
Definition: formats.h:64
An instance of a filter.
Definition: avfilter.h:338
int height
Definition: frame.h:353
internal API functions
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
static int query_formats(AVFilterContext *ctx)
Definition: vf_blackframe.c:49