FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
vf_mpdecimate.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2003 Rich Felker
3  * Copyright (c) 2012 Stefano Sabatini
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License along
18  * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
20  */
21 
22 /**
23  * @file mpdecimate filter, ported from libmpcodecs/vf_decimate.c by
24  * Rich Felker.
25  */
26 
27 #include "libavutil/opt.h"
28 #include "libavutil/pixdesc.h"
29 #include "libavutil/pixelutils.h"
30 #include "libavutil/timestamp.h"
31 #include "avfilter.h"
32 #include "internal.h"
33 #include "formats.h"
34 #include "video.h"
35 
36 typedef struct {
37  const AVClass *class;
38  int lo, hi; ///< lower and higher threshold number of differences
39  ///< values for 8x8 blocks
40 
41  float frac; ///< threshold of changed pixels over the total fraction
42 
43  int max_drop_count; ///< if positive: maximum number of sequential frames to drop
44  ///< if negative: minimum number of frames between two drops
45 
46  int drop_count; ///< if positive: number of frames sequentially dropped
47  ///< if negative: number of sequential frames which were not dropped
48 
49  int hsub, vsub; ///< chroma subsampling values
50  AVFrame *ref; ///< reference picture
51  av_pixelutils_sad_fn sad; ///< sum of absolute difference function
53 
54 #define OFFSET(x) offsetof(DecimateContext, x)
55 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
56 
57 static const AVOption mpdecimate_options[] = {
58  { "max", "set the maximum number of consecutive dropped frames (positive), or the minimum interval between dropped frames (negative)",
59  OFFSET(max_drop_count), AV_OPT_TYPE_INT, {.i64=0}, INT_MIN, INT_MAX, FLAGS },
60  { "hi", "set high dropping threshold", OFFSET(hi), AV_OPT_TYPE_INT, {.i64=64*12}, INT_MIN, INT_MAX, FLAGS },
61  { "lo", "set low dropping threshold", OFFSET(lo), AV_OPT_TYPE_INT, {.i64=64*5}, INT_MIN, INT_MAX, FLAGS },
62  { "frac", "set fraction dropping threshold", OFFSET(frac), AV_OPT_TYPE_FLOAT, {.dbl=0.33}, 0, 1, FLAGS },
63  { NULL }
64 };
65 
66 AVFILTER_DEFINE_CLASS(mpdecimate);
67 
68 /**
69  * Return 1 if the two planes are different, 0 otherwise.
70  */
71 static int diff_planes(AVFilterContext *ctx,
72  uint8_t *cur, int cur_linesize,
73  uint8_t *ref, int ref_linesize,
74  int w, int h)
75 {
76  DecimateContext *decimate = ctx->priv;
77 
78  int x, y;
79  int d, c = 0;
80  int t = (w/16)*(h/16)*decimate->frac;
81 
82  /* compute difference for blocks of 8x8 bytes */
83  for (y = 0; y < h-7; y += 4) {
84  for (x = 8; x < w-7; x += 4) {
85  d = decimate->sad(cur + y*cur_linesize + x, cur_linesize,
86  ref + y*ref_linesize + x, ref_linesize);
87  if (d > decimate->hi)
88  return 1;
89  if (d > decimate->lo) {
90  c++;
91  if (c > t)
92  return 1;
93  }
94  }
95  }
96  return 0;
97 }
98 
99 /**
100  * Tell if the frame should be decimated, for example if it is no much
101  * different with respect to the reference frame ref.
102  */
104  AVFrame *cur, AVFrame *ref)
105 {
106  DecimateContext *decimate = ctx->priv;
107  int plane;
108 
109  if (decimate->max_drop_count > 0 &&
110  decimate->drop_count >= decimate->max_drop_count)
111  return 0;
112  if (decimate->max_drop_count < 0 &&
113  (decimate->drop_count-1) > decimate->max_drop_count)
114  return 0;
115 
116  for (plane = 0; ref->data[plane] && ref->linesize[plane]; plane++) {
117  int vsub = plane == 1 || plane == 2 ? decimate->vsub : 0;
118  int hsub = plane == 1 || plane == 2 ? decimate->hsub : 0;
119  if (diff_planes(ctx,
120  cur->data[plane], cur->linesize[plane],
121  ref->data[plane], ref->linesize[plane],
122  FF_CEIL_RSHIFT(ref->width, hsub),
123  FF_CEIL_RSHIFT(ref->height, vsub)))
124  return 0;
125  }
126 
127  return 1;
128 }
129 
130 static av_cold int init(AVFilterContext *ctx)
131 {
132  DecimateContext *decimate = ctx->priv;
133 
134  decimate->sad = av_pixelutils_get_sad_fn(3, 3, 0, decimate); // 8x8, not aligned on blocksize
135  if (!decimate->sad)
136  return AVERROR(EINVAL);
137 
138  av_log(ctx, AV_LOG_VERBOSE, "max_drop_count:%d hi:%d lo:%d frac:%f\n",
139  decimate->max_drop_count, decimate->hi, decimate->lo, decimate->frac);
140 
141  return 0;
142 }
143 
144 static av_cold void uninit(AVFilterContext *ctx)
145 {
146  DecimateContext *decimate = ctx->priv;
147  av_frame_free(&decimate->ref);
148 }
149 
151 {
152  static const enum AVPixelFormat pix_fmts[] = {
160  };
161  AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
162  if (!fmts_list)
163  return AVERROR(ENOMEM);
164  return ff_set_common_formats(ctx, fmts_list);
165 }
166 
167 static int config_input(AVFilterLink *inlink)
168 {
169  AVFilterContext *ctx = inlink->dst;
170  DecimateContext *decimate = ctx->priv;
171  const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
172  decimate->hsub = pix_desc->log2_chroma_w;
173  decimate->vsub = pix_desc->log2_chroma_h;
174 
175  return 0;
176 }
177 
178 static int filter_frame(AVFilterLink *inlink, AVFrame *cur)
179 {
180  DecimateContext *decimate = inlink->dst->priv;
181  AVFilterLink *outlink = inlink->dst->outputs[0];
182  int ret;
183 
184  if (decimate->ref && decimate_frame(inlink->dst, cur, decimate->ref)) {
185  decimate->drop_count = FFMAX(1, decimate->drop_count+1);
186  } else {
187  av_frame_free(&decimate->ref);
188  decimate->ref = cur;
189  decimate->drop_count = FFMIN(-1, decimate->drop_count-1);
190 
191  if ((ret = ff_filter_frame(outlink, av_frame_clone(cur))) < 0)
192  return ret;
193  }
194 
195  av_log(inlink->dst, AV_LOG_DEBUG,
196  "%s pts:%s pts_time:%s drop_count:%d\n",
197  decimate->drop_count > 0 ? "drop" : "keep",
198  av_ts2str(cur->pts), av_ts2timestr(cur->pts, &inlink->time_base),
199  decimate->drop_count);
200 
201  if (decimate->drop_count > 0)
202  av_frame_free(&cur);
203 
204  return 0;
205 }
206 
207 static int request_frame(AVFilterLink *outlink)
208 {
209  DecimateContext *decimate = outlink->src->priv;
210  AVFilterLink *inlink = outlink->src->inputs[0];
211  int ret;
212 
213  do {
214  ret = ff_request_frame(inlink);
215  } while (decimate->drop_count > 0 && ret >= 0);
216 
217  return ret;
218 }
219 
220 static const AVFilterPad mpdecimate_inputs[] = {
221  {
222  .name = "default",
223  .type = AVMEDIA_TYPE_VIDEO,
224  .config_props = config_input,
225  .filter_frame = filter_frame,
226  },
227  { NULL }
228 };
229 
230 static const AVFilterPad mpdecimate_outputs[] = {
231  {
232  .name = "default",
233  .type = AVMEDIA_TYPE_VIDEO,
234  .request_frame = request_frame,
235  },
236  { NULL }
237 };
238 
240  .name = "mpdecimate",
241  .description = NULL_IF_CONFIG_SMALL("Remove near-duplicate frames."),
242  .init = init,
243  .uninit = uninit,
244  .priv_size = sizeof(DecimateContext),
245  .priv_class = &mpdecimate_class,
247  .inputs = mpdecimate_inputs,
248  .outputs = mpdecimate_outputs,
249 };