FFmpeg  4.4.5
vf_thumbnail.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2011 Smartjog S.A.S, Clément Bœsch <clement.boesch@smartjog.com>
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  * Potential thumbnail lookup filter to reduce the risk of an inappropriate
24  * selection (such as a black frame) we could get with an absolute seek.
25  *
26  * Simplified version of algorithm by Vadim Zaliva <lord@crocodile.org>.
27  * @see http://notbrainsurgery.livejournal.com/29773.html
28  */
29 
30 #include "libavutil/opt.h"
31 #include "libavutil/pixdesc.h"
32 #include "avfilter.h"
33 #include "internal.h"
34 
35 #define HIST_SIZE (3*256)
36 
37 struct thumb_frame {
38  AVFrame *buf; ///< cached frame
39  int histogram[HIST_SIZE]; ///< RGB color distribution histogram of the frame
40 };
41 
42 typedef struct ThumbContext {
43  const AVClass *class;
44  int n; ///< current frame
45  int n_frames; ///< number of frames for analysis
46  struct thumb_frame *frames; ///< the n_frames frames
47  AVRational tb; ///< copy of the input timebase to ease access
48 
49  int planewidth[4];
50  int planeheight[4];
51 } ThumbContext;
52 
53 #define OFFSET(x) offsetof(ThumbContext, x)
54 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
55 
56 static const AVOption thumbnail_options[] = {
57  { "n", "set the frames batch size", OFFSET(n_frames), AV_OPT_TYPE_INT, {.i64=100}, 2, INT_MAX, FLAGS },
58  { NULL }
59 };
60 
62 
64 {
65  ThumbContext *s = ctx->priv;
66 
67  s->frames = av_calloc(s->n_frames, sizeof(*s->frames));
68  if (!s->frames) {
70  "Allocation failure, try to lower the number of frames\n");
71  return AVERROR(ENOMEM);
72  }
73  av_log(ctx, AV_LOG_VERBOSE, "batch size: %d frames\n", s->n_frames);
74  return 0;
75 }
76 
77 /**
78  * @brief Compute Sum-square deviation to estimate "closeness".
79  * @param hist color distribution histogram
80  * @param median average color distribution histogram
81  * @return sum of squared errors
82  */
83 static double frame_sum_square_err(const int *hist, const double *median)
84 {
85  int i;
86  double err, sum_sq_err = 0;
87 
88  for (i = 0; i < HIST_SIZE; i++) {
89  err = median[i] - (double)hist[i];
90  sum_sq_err += err*err;
91  }
92  return sum_sq_err;
93 }
94 
96 {
97  AVFrame *picref;
98  ThumbContext *s = ctx->priv;
99  int i, j, best_frame_idx = 0;
100  int nb_frames = s->n;
101  double avg_hist[HIST_SIZE] = {0}, sq_err, min_sq_err = -1;
102 
103  // average histogram of the N frames
104  for (j = 0; j < FF_ARRAY_ELEMS(avg_hist); j++) {
105  for (i = 0; i < nb_frames; i++)
106  avg_hist[j] += (double)s->frames[i].histogram[j];
107  avg_hist[j] /= nb_frames;
108  }
109 
110  // find the frame closer to the average using the sum of squared errors
111  for (i = 0; i < nb_frames; i++) {
112  sq_err = frame_sum_square_err(s->frames[i].histogram, avg_hist);
113  if (i == 0 || sq_err < min_sq_err)
114  best_frame_idx = i, min_sq_err = sq_err;
115  }
116 
117  // free and reset everything (except the best frame buffer)
118  for (i = 0; i < nb_frames; i++) {
119  memset(s->frames[i].histogram, 0, sizeof(s->frames[i].histogram));
120  if (i != best_frame_idx)
121  av_frame_free(&s->frames[i].buf);
122  }
123  s->n = 0;
124 
125  // raise the chosen one
126  picref = s->frames[best_frame_idx].buf;
127  av_log(ctx, AV_LOG_INFO, "frame id #%d (pts_time=%f) selected "
128  "from a set of %d images\n", best_frame_idx,
129  picref->pts * av_q2d(s->tb), nb_frames);
130  s->frames[best_frame_idx].buf = NULL;
131 
132  return picref;
133 }
134 
135 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
136 {
137  int i, j;
138  AVFilterContext *ctx = inlink->dst;
139  ThumbContext *s = ctx->priv;
140  AVFilterLink *outlink = ctx->outputs[0];
141  int *hist = s->frames[s->n].histogram;
142  const uint8_t *p = frame->data[0];
143 
144  // keep a reference of each frame
145  s->frames[s->n].buf = frame;
146 
147  // update current frame histogram
148  switch (inlink->format) {
149  case AV_PIX_FMT_RGB24:
150  case AV_PIX_FMT_BGR24:
151  for (j = 0; j < inlink->h; j++) {
152  for (i = 0; i < inlink->w; i++) {
153  hist[0*256 + p[i*3 ]]++;
154  hist[1*256 + p[i*3 + 1]]++;
155  hist[2*256 + p[i*3 + 2]]++;
156  }
157  p += frame->linesize[0];
158  }
159  break;
160  case AV_PIX_FMT_RGB0:
161  case AV_PIX_FMT_BGR0:
162  case AV_PIX_FMT_RGBA:
163  case AV_PIX_FMT_BGRA:
164  for (j = 0; j < inlink->h; j++) {
165  for (i = 0; i < inlink->w; i++) {
166  hist[0*256 + p[i*4 ]]++;
167  hist[1*256 + p[i*4 + 1]]++;
168  hist[2*256 + p[i*4 + 2]]++;
169  }
170  p += frame->linesize[0];
171  }
172  break;
173  case AV_PIX_FMT_0RGB:
174  case AV_PIX_FMT_0BGR:
175  case AV_PIX_FMT_ARGB:
176  case AV_PIX_FMT_ABGR:
177  for (j = 0; j < inlink->h; j++) {
178  for (i = 0; i < inlink->w; i++) {
179  hist[0*256 + p[i*4 + 1]]++;
180  hist[1*256 + p[i*4 + 2]]++;
181  hist[2*256 + p[i*4 + 3]]++;
182  }
183  p += frame->linesize[0];
184  }
185  break;
186  default:
187  for (int plane = 0; plane < 3; plane++) {
188  const uint8_t *p = frame->data[plane];
189  for (j = 0; j < s->planeheight[plane]; j++) {
190  for (i = 0; i < s->planewidth[plane]; i++)
191  hist[256*plane + p[i]]++;
192  p += frame->linesize[plane];
193  }
194  }
195  break;
196  }
197 
198  // no selection until the buffer of N frames is filled up
199  s->n++;
200  if (s->n < s->n_frames)
201  return 0;
202 
203  return ff_filter_frame(outlink, get_best_frame(ctx));
204 }
205 
207 {
208  int i;
209  ThumbContext *s = ctx->priv;
210  for (i = 0; i < s->n_frames && s->frames && s->frames[i].buf; i++)
211  av_frame_free(&s->frames[i].buf);
212  av_freep(&s->frames);
213 }
214 
215 static int request_frame(AVFilterLink *link)
216 {
217  AVFilterContext *ctx = link->src;
218  ThumbContext *s = ctx->priv;
219  int ret = ff_request_frame(ctx->inputs[0]);
220 
221  if (ret == AVERROR_EOF && s->n) {
222  ret = ff_filter_frame(link, get_best_frame(ctx));
223  if (ret < 0)
224  return ret;
225  ret = AVERROR_EOF;
226  }
227  if (ret < 0)
228  return ret;
229  return 0;
230 }
231 
232 static int config_props(AVFilterLink *inlink)
233 {
234  AVFilterContext *ctx = inlink->dst;
235  ThumbContext *s = ctx->priv;
237 
238  s->tb = inlink->time_base;
239  s->planewidth[1] = s->planewidth[2] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
240  s->planewidth[0] = s->planewidth[3] = inlink->w;
241  s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
242  s->planeheight[0] = s->planeheight[3] = inlink->h;
243 
244  return 0;
245 }
246 
248 {
249  static const enum AVPixelFormat pix_fmts[] = {
264  };
266  if (!fmts_list)
267  return AVERROR(ENOMEM);
268  return ff_set_common_formats(ctx, fmts_list);
269 }
270 
271 static const AVFilterPad thumbnail_inputs[] = {
272  {
273  .name = "default",
274  .type = AVMEDIA_TYPE_VIDEO,
275  .config_props = config_props,
276  .filter_frame = filter_frame,
277  },
278  { NULL }
279 };
280 
281 static const AVFilterPad thumbnail_outputs[] = {
282  {
283  .name = "default",
284  .type = AVMEDIA_TYPE_VIDEO,
285  .request_frame = request_frame,
286  },
287  { NULL }
288 };
289 
291  .name = "thumbnail",
292  .description = NULL_IF_CONFIG_SMALL("Select the most representative frame in a given sequence of consecutive frames."),
293  .priv_size = sizeof(ThumbContext),
294  .init = init,
295  .uninit = uninit,
299  .priv_class = &thumbnail_class,
301 };
static const AVFilterPad inputs[]
Definition: af_acontrast.c:193
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
#define av_cold
Definition: attributes.h:88
uint8_t
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1096
int ff_request_frame(AVFilterLink *link)
Request an input frame from the filter at the other end of the link.
Definition: avfilter.c:408
Main libavfilter public API header.
#define flags(name, subs,...)
Definition: cbs_av1.c:572
#define s(width, name)
Definition: cbs_vp9.c:257
#define AV_CEIL_RSHIFT(a, b)
Definition: common.h:58
#define NULL
Definition: coverity.c:32
static AVFrame * frame
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:587
AVFilterFormats * ff_make_format_list(const int *fmts)
Create a list of supported formats.
Definition: formats.c:286
@ AV_OPT_TYPE_INT
Definition: opt.h:225
#define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC
Some filters support a generic "enable" expression option that can be used to enable or disable a fil...
Definition: avfilter.h:126
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define AVERROR(e)
Definition: error.h:43
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:203
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:210
#define AV_LOG_INFO
Standard information.
Definition: log.h:205
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
static double av_q2d(AVRational a)
Convert an AVRational to a double.
Definition: rational.h:104
void * av_calloc(size_t nmemb, size_t size)
Non-inlined equivalent of av_mallocz_array().
Definition: mem.c:245
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
int i
Definition: input.c:407
common internal API header
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:309
const char * desc
Definition: libsvtav1.c:79
AVOptions.
const AVPixFmtDescriptor * av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:2573
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
@ AV_PIX_FMT_NONE
Definition: pixfmt.h:65
@ AV_PIX_FMT_RGB24
packed RGB 8:8:8, 24bpp, RGBRGB...
Definition: pixfmt.h:68
@ AV_PIX_FMT_YUV420P
planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)
Definition: pixfmt.h:66
@ AV_PIX_FMT_YUV440P
planar YUV 4:4:0 (1 Cr & Cb sample per 1x2 Y samples)
Definition: pixfmt.h:99
@ AV_PIX_FMT_BGR0
packed BGR 8:8:8, 32bpp, BGRXBGRX... X=unused/undefined
Definition: pixfmt.h:240
@ AV_PIX_FMT_YUV422P
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:70
@ AV_PIX_FMT_ARGB
packed ARGB 8:8:8:8, 32bpp, ARGBARGB...
Definition: pixfmt.h:92
@ AV_PIX_FMT_BGRA
packed BGRA 8:8:8:8, 32bpp, BGRABGRA...
Definition: pixfmt.h:95
@ AV_PIX_FMT_ABGR
packed ABGR 8:8:8:8, 32bpp, ABGRABGR...
Definition: pixfmt.h:94
@ AV_PIX_FMT_YUVA420P
planar YUV 4:2:0, 20bpp, (1 Cr & Cb sample per 2x2 Y & A samples)
Definition: pixfmt.h:101
@ AV_PIX_FMT_YUVJ440P
planar YUV 4:4:0 full scale (JPEG), deprecated in favor of AV_PIX_FMT_YUV440P and setting color_range
Definition: pixfmt.h:100
@ AV_PIX_FMT_YUV410P
planar YUV 4:1:0, 9bpp, (1 Cr & Cb sample per 4x4 Y samples)
Definition: pixfmt.h:72
@ AV_PIX_FMT_0BGR
packed BGR 8:8:8, 32bpp, XBGRXBGR... X=unused/undefined
Definition: pixfmt.h:239
@ AV_PIX_FMT_YUV411P
planar YUV 4:1:1, 12bpp, (1 Cr & Cb sample per 4x1 Y samples)
Definition: pixfmt.h:73
@ AV_PIX_FMT_RGBA
packed RGBA 8:8:8:8, 32bpp, RGBARGBA...
Definition: pixfmt.h:93
@ AV_PIX_FMT_YUV444P
planar YUV 4:4:4, 24bpp, (1 Cr & Cb sample per 1x1 Y samples)
Definition: pixfmt.h:71
@ AV_PIX_FMT_YUVA444P
planar YUV 4:4:4 32bpp, (1 Cr & Cb sample per 1x1 Y & A samples)
Definition: pixfmt.h:177
@ AV_PIX_FMT_YUVJ411P
planar YUV 4:1:1, 12bpp, (1 Cr & Cb sample per 4x1 Y samples) full scale (JPEG), deprecated in favor ...
Definition: pixfmt.h:258
@ AV_PIX_FMT_GBRAP
planar GBRA 4:4:4:4 32bpp
Definition: pixfmt.h:215
@ AV_PIX_FMT_YUVJ422P
planar YUV 4:2:2, 16bpp, full scale (JPEG), deprecated in favor of AV_PIX_FMT_YUV422P and setting col...
Definition: pixfmt.h:79
@ AV_PIX_FMT_RGB0
packed RGB 8:8:8, 32bpp, RGBXRGBX... X=unused/undefined
Definition: pixfmt.h:238
@ AV_PIX_FMT_YUVA422P
planar YUV 4:2:2 24bpp, (1 Cr & Cb sample per 2x1 Y & A samples)
Definition: pixfmt.h:176
@ AV_PIX_FMT_BGR24
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:69
@ AV_PIX_FMT_GBRP
planar GBR 4:4:4 24bpp
Definition: pixfmt.h:168
@ AV_PIX_FMT_0RGB
packed RGB 8:8:8, 32bpp, XRGBXRGB... X=unused/undefined
Definition: pixfmt.h:237
@ AV_PIX_FMT_YUVJ444P
planar YUV 4:4:4, 24bpp, full scale (JPEG), deprecated in favor of AV_PIX_FMT_YUV444P and setting col...
Definition: pixfmt.h:80
@ AV_PIX_FMT_YUVJ420P
planar YUV 4:2:0, 12bpp, full scale (JPEG), deprecated in favor of AV_PIX_FMT_YUV420P and setting col...
Definition: pixfmt.h:78
#define FF_ARRAY_ELEMS(a)
Describe the class of an AVClass context structure.
Definition: log.h:67
An instance of a filter.
Definition: avfilter.h:341
A list of supported formats for one end of a filter link.
Definition: formats.h:65
A filter pad used for either input or output.
Definition: internal.h:54
const char * name
Pad name.
Definition: internal.h:60
Filter definition.
Definition: avfilter.h:145
const char * name
Filter name.
Definition: avfilter.h:149
This structure describes decoded (raw) audio or video data.
Definition: frame.h:318
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition: frame.h:411
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:332
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:349
AVOption.
Definition: opt.h:248
Descriptor that unambiguously describes how the bits of a pixel are stored in the up to 4 data planes...
Definition: pixdesc.h:81
Rational number (pair of numerator and denominator).
Definition: rational.h:58
AVRational tb
copy of the input timebase to ease access
Definition: vf_thumbnail.c:47
struct thumb_frame * frames
the n_frames frames
Definition: vf_thumbnail.c:46
int n
current frame
Definition: vf_thumbnail.c:44
int planewidth[4]
Definition: vf_thumbnail.c:49
int n_frames
number of frames for analysis
Definition: vf_thumbnail.c:45
int planeheight[4]
Definition: vf_thumbnail.c:50
AVFrame * buf
cached frame
Definition: vf_thumbnail.c:38
int histogram[HIST_SIZE]
RGB color distribution histogram of the frame.
Definition: vf_thumbnail.c:39
#define av_freep(p)
#define av_log(a,...)
AVFormatContext * ctx
Definition: movenc.c:48
AVFILTER_DEFINE_CLASS(thumbnail)
static const AVOption thumbnail_options[]
Definition: vf_thumbnail.c:56
AVFilter ff_vf_thumbnail
Definition: vf_thumbnail.c:290
static int query_formats(AVFilterContext *ctx)
Definition: vf_thumbnail.c:247
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
Definition: vf_thumbnail.c:135
#define FLAGS
Definition: vf_thumbnail.c:54
static AVFrame * get_best_frame(AVFilterContext *ctx)
Definition: vf_thumbnail.c:95
#define HIST_SIZE
Definition: vf_thumbnail.c:35
static int request_frame(AVFilterLink *link)
Definition: vf_thumbnail.c:215
static const AVFilterPad thumbnail_inputs[]
Definition: vf_thumbnail.c:271
static int config_props(AVFilterLink *inlink)
Definition: vf_thumbnail.c:232
static av_cold int init(AVFilterContext *ctx)
Definition: vf_thumbnail.c:63
static av_cold void uninit(AVFilterContext *ctx)
Definition: vf_thumbnail.c:206
static double frame_sum_square_err(const int *hist, const double *median)
Compute Sum-square deviation to estimate "closeness".
Definition: vf_thumbnail.c:83
#define OFFSET(x)
Definition: vf_thumbnail.c:53
static const AVFilterPad thumbnail_outputs[]
Definition: vf_thumbnail.c:281
static int thumbnail(AVFilterContext *ctx, int *histogram, AVFrame *in)