FFmpeg  2.6.9
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vf_mpdecimate.c
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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  emms_c();
125  return 0;
126  }
127  }
128 
129  emms_c();
130  return 1;
131 }
132 
133 static av_cold int init(AVFilterContext *ctx)
134 {
135  DecimateContext *decimate = ctx->priv;
136 
137  decimate->sad = av_pixelutils_get_sad_fn(3, 3, 0, decimate); // 8x8, not aligned on blocksize
138  if (!decimate->sad)
139  return AVERROR(EINVAL);
140 
141  av_log(ctx, AV_LOG_VERBOSE, "max_drop_count:%d hi:%d lo:%d frac:%f\n",
142  decimate->max_drop_count, decimate->hi, decimate->lo, decimate->frac);
143 
144  return 0;
145 }
146 
147 static av_cold void uninit(AVFilterContext *ctx)
148 {
149  DecimateContext *decimate = ctx->priv;
150  av_frame_free(&decimate->ref);
151 }
152 
154 {
155  static const enum AVPixelFormat pix_fmts[] = {
163  };
164 
166 
167  return 0;
168 }
169 
170 static int config_input(AVFilterLink *inlink)
171 {
172  AVFilterContext *ctx = inlink->dst;
173  DecimateContext *decimate = ctx->priv;
174  const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
175  decimate->hsub = pix_desc->log2_chroma_w;
176  decimate->vsub = pix_desc->log2_chroma_h;
177 
178  return 0;
179 }
180 
181 static int filter_frame(AVFilterLink *inlink, AVFrame *cur)
182 {
183  DecimateContext *decimate = inlink->dst->priv;
184  AVFilterLink *outlink = inlink->dst->outputs[0];
185  int ret;
186 
187  if (decimate->ref && decimate_frame(inlink->dst, cur, decimate->ref)) {
188  decimate->drop_count = FFMAX(1, decimate->drop_count+1);
189  } else {
190  av_frame_free(&decimate->ref);
191  decimate->ref = cur;
192  decimate->drop_count = FFMIN(-1, decimate->drop_count-1);
193 
194  if (ret = ff_filter_frame(outlink, av_frame_clone(cur)) < 0)
195  return ret;
196  }
197 
198  av_log(inlink->dst, AV_LOG_DEBUG,
199  "%s pts:%s pts_time:%s drop_count:%d\n",
200  decimate->drop_count > 0 ? "drop" : "keep",
201  av_ts2str(cur->pts), av_ts2timestr(cur->pts, &inlink->time_base),
202  decimate->drop_count);
203 
204  if (decimate->drop_count > 0)
205  av_frame_free(&cur);
206 
207  return 0;
208 }
209 
210 static int request_frame(AVFilterLink *outlink)
211 {
212  DecimateContext *decimate = outlink->src->priv;
213  AVFilterLink *inlink = outlink->src->inputs[0];
214  int ret;
215 
216  do {
217  ret = ff_request_frame(inlink);
218  } while (decimate->drop_count > 0 && ret >= 0);
219 
220  return ret;
221 }
222 
223 static const AVFilterPad mpdecimate_inputs[] = {
224  {
225  .name = "default",
226  .type = AVMEDIA_TYPE_VIDEO,
227  .config_props = config_input,
228  .filter_frame = filter_frame,
229  },
230  { NULL }
231 };
232 
233 static const AVFilterPad mpdecimate_outputs[] = {
234  {
235  .name = "default",
236  .type = AVMEDIA_TYPE_VIDEO,
237  .request_frame = request_frame,
238  },
239  { NULL }
240 };
241 
243  .name = "mpdecimate",
244  .description = NULL_IF_CONFIG_SMALL("Remove near-duplicate frames."),
245  .init = init,
246  .uninit = uninit,
247  .priv_size = sizeof(DecimateContext),
248  .priv_class = &mpdecimate_class,
250  .inputs = mpdecimate_inputs,
251  .outputs = mpdecimate_outputs,
252 };