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/pixdesc.h"
28 #include "libavutil/timestamp.h"
29 #include "libavcodec/dsputil.h"
36 int lo, hi; ///< lower and higher threshold number of differences
37 ///< values for 8x8 blocks
39 float frac; ///< threshold of changed pixels over the total fraction
41 int max_drop_count; ///< if positive: maximum number of sequential frames to drop
42 ///< if negative: minimum number of frames between two drops
44 int drop_count; ///< if positive: number of frames sequentially dropped
45 ///< if negative: number of sequential frames which were not dropped
47 int hsub, vsub; ///< chroma subsampling values
48 AVFilterBufferRef *ref; ///< reference picture
49 DSPContext dspctx; ///< context providing optimized diff routines
50 AVCodecContext *avctx; ///< codec context required for the DSPContext
54 * Return 1 if the two planes are different, 0 otherwise.
56 static int diff_planes(AVFilterContext *ctx,
57 uint8_t *cur, uint8_t *ref, int linesize,
60 DecimateContext *decimate = ctx->priv;
61 DSPContext *dspctx = &decimate->dspctx;
65 int t = (w/16)*(h/16)*decimate->frac;
68 /* compute difference for blocks of 8x8 bytes */
69 for (y = 0; y < h-7; y += 4) {
70 for (x = 8; x < w-7; x += 4) {
71 dspctx->diff_pixels(block,
73 ref+x+y*linesize, linesize);
74 d = dspctx->sum_abs_dctelem(block);
77 if (d > decimate->lo) {
88 * Tell if the frame should be decimated, for example if it is no much
89 * different with respect to the reference frame ref.
91 static int decimate_frame(AVFilterContext *ctx,
92 AVFilterBufferRef *cur, AVFilterBufferRef *ref)
94 DecimateContext *decimate = ctx->priv;
97 if (decimate->max_drop_count > 0 &&
98 decimate->drop_count >= decimate->max_drop_count)
100 if (decimate->max_drop_count < 0 &&
101 (decimate->drop_count-1) > decimate->max_drop_count)
104 for (plane = 0; ref->data[plane] && ref->linesize[plane]; plane++) {
105 int vsub = plane == 1 || plane == 2 ? decimate->vsub : 0;
106 int hsub = plane == 1 || plane == 2 ? decimate->hsub : 0;
108 cur->data[plane], ref->data[plane], ref->linesize[plane],
109 ref->video->w>>hsub, ref->video->h>>vsub))
116 static av_cold int init(AVFilterContext *ctx, const char *args)
118 DecimateContext *decimate = ctx->priv;
120 /* set default values */
121 decimate->drop_count = decimate->max_drop_count = 0;
123 decimate->hi = 64*12;
124 decimate->frac = 0.33;
128 int n = sscanf(args, "%d%c%d%c%d%c%f%c",
129 &decimate->max_drop_count, &c1,
130 &decimate->hi, &c2, &decimate->lo, &c3,
131 &decimate->frac, &c4);
133 (n != 3 || c1 != ':') &&
134 (n != 5 || c1 != ':' || c2 != ':') &&
135 (n != 7 || c1 != ':' || c2 != ':' || c3 != ':')) {
136 av_log(ctx, AV_LOG_ERROR,
137 "Invalid syntax for argument '%s': "
138 "must be in the form 'max:hi:lo:frac'\n", args);
139 return AVERROR(EINVAL);
143 av_log(ctx, AV_LOG_VERBOSE, "max_drop_count:%d hi:%d lo:%d frac:%f\n",
144 decimate->max_drop_count, decimate->hi, decimate->lo, decimate->frac);
146 decimate->avctx = avcodec_alloc_context3(NULL);
147 if (!decimate->avctx)
148 return AVERROR(ENOMEM);
149 dsputil_init(&decimate->dspctx, decimate->avctx);
154 static av_cold void uninit(AVFilterContext *ctx)
156 DecimateContext *decimate = ctx->priv;
157 avfilter_unref_bufferp(&decimate->ref);
158 avcodec_close(decimate->avctx);
159 av_freep(&decimate->avctx);
162 static int query_formats(AVFilterContext *ctx)
164 static const enum AVPixelFormat pix_fmts[] = {
165 AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P,
166 AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV411P,
167 AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV440P,
168 AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ422P,
169 AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ440P,
174 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
179 static int config_input(AVFilterLink *inlink)
181 AVFilterContext *ctx = inlink->dst;
182 DecimateContext *decimate = ctx->priv;
183 const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
184 decimate->hsub = pix_desc->log2_chroma_w;
185 decimate->vsub = pix_desc->log2_chroma_h;
190 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *cur)
192 DecimateContext *decimate = inlink->dst->priv;
193 AVFilterLink *outlink = inlink->dst->outputs[0];
196 if (decimate->ref && decimate_frame(inlink->dst, cur, decimate->ref)) {
197 decimate->drop_count = FFMAX(1, decimate->drop_count+1);
199 avfilter_unref_buffer(decimate->ref);
201 decimate->drop_count = FFMIN(-1, decimate->drop_count-1);
203 if (ret = ff_filter_frame(outlink, avfilter_ref_buffer(cur, ~AV_PERM_WRITE)) < 0)
207 av_log(inlink->dst, AV_LOG_DEBUG,
208 "%s pts:%s pts_time:%s drop_count:%d\n",
209 decimate->drop_count > 0 ? "drop" : "keep",
210 av_ts2str(cur->pts), av_ts2timestr(cur->pts, &inlink->time_base),
211 decimate->drop_count);
213 if (decimate->drop_count > 0)
214 avfilter_unref_buffer(cur);
219 static int request_frame(AVFilterLink *outlink)
221 DecimateContext *decimate = outlink->src->priv;
222 AVFilterLink *inlink = outlink->src->inputs[0];
226 ret = ff_request_frame(inlink);
227 } while (decimate->drop_count > 0 && ret >= 0);
232 static const AVFilterPad decimate_inputs[] = {
235 .type = AVMEDIA_TYPE_VIDEO,
236 .get_video_buffer = ff_null_get_video_buffer,
237 .config_props = config_input,
238 .filter_frame = filter_frame,
239 .min_perms = AV_PERM_READ | AV_PERM_PRESERVE,
244 static const AVFilterPad decimate_outputs[] = {
247 .type = AVMEDIA_TYPE_VIDEO,
248 .request_frame = request_frame,
253 AVFilter avfilter_vf_decimate = {
255 .description = NULL_IF_CONFIG_SMALL("Remove near-duplicate frames."),
259 .priv_size = sizeof(DecimateContext),
260 .query_formats = query_formats,
261 .inputs = decimate_inputs,
262 .outputs = decimate_outputs,