2 * Copyright (c) 2003 Rich Felker
3 * Copyright (c) 2012 Stefano Sabatini
5 * This file is part of FFmpeg.
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.
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.
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.
23 * @file decimate filter, ported from libmpcodecs/vf_decimate.c by
27 #include "libavutil/opt.h"
28 #include "libavutil/pixdesc.h"
29 #include "libavutil/timestamp.h"
30 #include "libavcodec/dsputil.h"
38 int lo, hi; ///< lower and higher threshold number of differences
39 ///< values for 8x8 blocks
41 float frac; ///< threshold of changed pixels over the total fraction
43 int max_drop_count; ///< if positive: maximum number of sequential frames to drop
44 ///< if negative: minimum number of frames between two drops
46 int drop_count; ///< if positive: number of frames sequentially dropped
47 ///< if negative: number of sequential frames which were not dropped
49 int hsub, vsub; ///< chroma subsampling values
50 AVFilterBufferRef *ref; ///< reference picture
51 DSPContext dspctx; ///< context providing optimized diff routines
52 AVCodecContext *avctx; ///< codec context required for the DSPContext
55 #define OFFSET(x) offsetof(DecimateContext, x)
56 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
58 static const AVOption decimate_options[] = {
59 { "max", "set the maximum number of consecutive dropped frames (positive), or the minimum interval between dropped frames (negative)",
60 OFFSET(max_drop_count), AV_OPT_TYPE_INT, {.i64=0}, INT_MIN, INT_MAX, FLAGS },
61 { "hi", "set high dropping threshold", OFFSET(hi), AV_OPT_TYPE_INT, {.i64=64*12}, INT_MIN, INT_MAX, FLAGS },
62 { "lo", "set low dropping threshold", OFFSET(lo), AV_OPT_TYPE_INT, {.i64=64*5}, INT_MIN, INT_MAX, FLAGS },
63 { "frac", "set fraction dropping threshold", OFFSET(frac), AV_OPT_TYPE_FLOAT, {.dbl=0.33}, 0, 1, FLAGS },
67 AVFILTER_DEFINE_CLASS(decimate);
70 * Return 1 if the two planes are different, 0 otherwise.
72 static int diff_planes(AVFilterContext *ctx,
73 uint8_t *cur, uint8_t *ref, int linesize,
76 DecimateContext *decimate = ctx->priv;
77 DSPContext *dspctx = &decimate->dspctx;
81 int t = (w/16)*(h/16)*decimate->frac;
84 /* compute difference for blocks of 8x8 bytes */
85 for (y = 0; y < h-7; y += 4) {
86 for (x = 8; x < w-7; x += 4) {
87 dspctx->diff_pixels(block,
89 ref+x+y*linesize, linesize);
90 d = dspctx->sum_abs_dctelem(block);
93 if (d > decimate->lo) {
104 * Tell if the frame should be decimated, for example if it is no much
105 * different with respect to the reference frame ref.
107 static int decimate_frame(AVFilterContext *ctx,
108 AVFilterBufferRef *cur, AVFilterBufferRef *ref)
110 DecimateContext *decimate = ctx->priv;
113 if (decimate->max_drop_count > 0 &&
114 decimate->drop_count >= decimate->max_drop_count)
116 if (decimate->max_drop_count < 0 &&
117 (decimate->drop_count-1) > decimate->max_drop_count)
120 for (plane = 0; ref->data[plane] && ref->linesize[plane]; plane++) {
121 int vsub = plane == 1 || plane == 2 ? decimate->vsub : 0;
122 int hsub = plane == 1 || plane == 2 ? decimate->hsub : 0;
124 cur->data[plane], ref->data[plane], ref->linesize[plane],
125 ref->video->w>>hsub, ref->video->h>>vsub))
132 static av_cold int init(AVFilterContext *ctx, const char *args)
134 DecimateContext *decimate = ctx->priv;
135 static const char *shorthand[] = { "max", "hi", "lo", "frac", NULL };
138 decimate->class = &decimate_class;
139 av_opt_set_defaults(decimate);
141 if ((ret = av_opt_set_from_string(decimate, args, shorthand, "=", ":")) < 0)
144 av_log(ctx, AV_LOG_VERBOSE, "max_drop_count:%d hi:%d lo:%d frac:%f\n",
145 decimate->max_drop_count, decimate->hi, decimate->lo, decimate->frac);
147 decimate->avctx = avcodec_alloc_context3(NULL);
148 if (!decimate->avctx)
149 return AVERROR(ENOMEM);
150 dsputil_init(&decimate->dspctx, decimate->avctx);
155 static av_cold void uninit(AVFilterContext *ctx)
157 DecimateContext *decimate = ctx->priv;
158 avfilter_unref_bufferp(&decimate->ref);
159 avcodec_close(decimate->avctx);
160 av_opt_free(decimate);
161 av_freep(&decimate->avctx);
164 static int query_formats(AVFilterContext *ctx)
166 static const enum AVPixelFormat pix_fmts[] = {
167 AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P,
168 AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV411P,
169 AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV440P,
170 AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ422P,
171 AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ440P,
176 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
181 static int config_input(AVFilterLink *inlink)
183 AVFilterContext *ctx = inlink->dst;
184 DecimateContext *decimate = ctx->priv;
185 const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
186 decimate->hsub = pix_desc->log2_chroma_w;
187 decimate->vsub = pix_desc->log2_chroma_h;
192 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *cur)
194 DecimateContext *decimate = inlink->dst->priv;
195 AVFilterLink *outlink = inlink->dst->outputs[0];
198 if (decimate->ref && decimate_frame(inlink->dst, cur, decimate->ref)) {
199 decimate->drop_count = FFMAX(1, decimate->drop_count+1);
201 avfilter_unref_buffer(decimate->ref);
203 decimate->drop_count = FFMIN(-1, decimate->drop_count-1);
205 if (ret = ff_filter_frame(outlink, avfilter_ref_buffer(cur, ~AV_PERM_WRITE)) < 0)
209 av_log(inlink->dst, AV_LOG_DEBUG,
210 "%s pts:%s pts_time:%s drop_count:%d\n",
211 decimate->drop_count > 0 ? "drop" : "keep",
212 av_ts2str(cur->pts), av_ts2timestr(cur->pts, &inlink->time_base),
213 decimate->drop_count);
215 if (decimate->drop_count > 0)
216 avfilter_unref_buffer(cur);
221 static int request_frame(AVFilterLink *outlink)
223 DecimateContext *decimate = outlink->src->priv;
224 AVFilterLink *inlink = outlink->src->inputs[0];
228 ret = ff_request_frame(inlink);
229 } while (decimate->drop_count > 0 && ret >= 0);
234 static const AVFilterPad decimate_inputs[] = {
237 .type = AVMEDIA_TYPE_VIDEO,
238 .get_video_buffer = ff_null_get_video_buffer,
239 .config_props = config_input,
240 .filter_frame = filter_frame,
241 .min_perms = AV_PERM_READ | AV_PERM_PRESERVE,
246 static const AVFilterPad decimate_outputs[] = {
249 .type = AVMEDIA_TYPE_VIDEO,
250 .request_frame = request_frame,
255 AVFilter avfilter_vf_decimate = {
257 .description = NULL_IF_CONFIG_SMALL("Remove near-duplicate frames."),
261 .priv_size = sizeof(DecimateContext),
262 .query_formats = query_formats,
263 .inputs = decimate_inputs,
264 .outputs = decimate_outputs,
265 .priv_class = &decimate_class,