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/*
* Copyright (c) 2003 Rich Felker
* Copyright (c) 2012 Stefano Sabatini
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with FFmpeg; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/**
* @file decimate filter, ported from libmpcodecs/vf_decimate.c by
* Rich Felker.
*/
#include "libavutil/pixdesc.h"
#include "libavutil/timestamp.h"
#include "libavcodec/dsputil.h"
#include "avfilter.h"
#include "internal.h"
#include "formats.h"
#include "video.h"
typedef struct {
int lo, hi; ///< lower and higher threshold number of differences
///< values for 8x8 blocks
float frac; ///< threshold of changed pixels over the total fraction
int max_drop_count; ///< if positive: maximum number of sequential frames to drop
///< if negative: minimum number of frames between two drops
int drop_count; ///< if positive: number of frames sequentially dropped
///< if negative: number of sequential frames which were not dropped
int hsub, vsub; ///< chroma subsampling values
AVFilterBufferRef *ref; ///< reference picture
DSPContext dspctx; ///< context providing optimized diff routines
AVCodecContext *avctx; ///< codec context required for the DSPContext
} DecimateContext;
/**
* Return 1 if the two planes are different, 0 otherwise.
*/
static int diff_planes(AVFilterContext *ctx,
uint8_t *cur, uint8_t *ref, int linesize,
int w, int h)
{
DecimateContext *decimate = ctx->priv;
DSPContext *dspctx = &decimate->dspctx;
int x, y;
int d, c = 0;
int t = (w/16)*(h/16)*decimate->frac;
DCTELEM block[8*8];
/* compute difference for blocks of 8x8 bytes */
for (y = 0; y < h-7; y += 4) {
for (x = 8; x < w-7; x += 4) {
dspctx->diff_pixels(block,
cur+x+y*linesize,
ref+x+y*linesize, linesize);
d = dspctx->sum_abs_dctelem(block);
if (d > decimate->hi)
return 1;
if (d > decimate->lo) {
c++;
if (c > t)
return 1;
}
}
}
return 0;
}
/**
* Tell if the frame should be decimated, for example if it is no much
* different with respect to the reference frame ref.
*/
static int decimate_frame(AVFilterContext *ctx,
AVFilterBufferRef *cur, AVFilterBufferRef *ref)
{
DecimateContext *decimate = ctx->priv;
int plane;
if (decimate->max_drop_count > 0 &&
decimate->drop_count >= decimate->max_drop_count)
return 0;
if (decimate->max_drop_count < 0 &&
(decimate->drop_count-1) > decimate->max_drop_count)
return 0;
for (plane = 0; ref->data[plane] && ref->linesize[plane]; plane++) {
int vsub = plane == 1 || plane == 2 ? decimate->vsub : 0;
int hsub = plane == 1 || plane == 2 ? decimate->hsub : 0;
if (diff_planes(ctx,
cur->data[plane], ref->data[plane], ref->linesize[plane],
ref->video->w>>hsub, ref->video->h>>vsub))
return 0;
}
return 1;
}
static av_cold int init(AVFilterContext *ctx, const char *args)
{
DecimateContext *decimate = ctx->priv;
/* set default values */
decimate->drop_count = decimate->max_drop_count = 0;
decimate->lo = 64*5;
decimate->hi = 64*12;
decimate->frac = 0.33;
if (args) {
char c1, c2, c3, c4;
int n = sscanf(args, "%d%c%d%c%d%c%f%c",
&decimate->max_drop_count, &c1,
&decimate->hi, &c2, &decimate->lo, &c3,
&decimate->frac, &c4);
if (n != 1 &&
(n != 3 || c1 != ':') &&
(n != 5 || c1 != ':' || c2 != ':') &&
(n != 7 || c1 != ':' || c2 != ':' || c3 != ':')) {
av_log(ctx, AV_LOG_ERROR,
"Invalid syntax for argument '%s': "
"must be in the form 'max:hi:lo:frac'\n", args);
return AVERROR(EINVAL);
}
}
av_log(ctx, AV_LOG_VERBOSE, "max_drop_count:%d hi:%d lo:%d frac:%f\n",
decimate->max_drop_count, decimate->hi, decimate->lo, decimate->frac);
decimate->avctx = avcodec_alloc_context3(NULL);
if (!decimate->avctx)
return AVERROR(ENOMEM);
dsputil_init(&decimate->dspctx, decimate->avctx);
return 0;
}
static av_cold void uninit(AVFilterContext *ctx)
{
DecimateContext *decimate = ctx->priv;
avfilter_unref_bufferp(&decimate->ref);
avcodec_close(decimate->avctx);
av_freep(&decimate->avctx);
}
static int query_formats(AVFilterContext *ctx)
{
static const enum PixelFormat pix_fmts[] = {
PIX_FMT_YUV444P, PIX_FMT_YUV422P,
PIX_FMT_YUV420P, PIX_FMT_YUV411P,
PIX_FMT_YUV410P, PIX_FMT_YUV440P,
PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P,
PIX_FMT_YUVJ420P, PIX_FMT_YUVJ440P,
PIX_FMT_YUVA420P,
PIX_FMT_NONE
};
ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
return 0;
}
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
DecimateContext *decimate = ctx->priv;
const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[inlink->format];
decimate->hsub = pix_desc->log2_chroma_w;
decimate->vsub = pix_desc->log2_chroma_h;
return 0;
}
static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref) { return 0; }
static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir) { return 0; }
static int end_frame(AVFilterLink *inlink)
{
DecimateContext *decimate = inlink->dst->priv;
AVFilterBufferRef *cur = inlink->cur_buf;
AVFilterLink *outlink = inlink->dst->outputs[0];
int ret;
if (decimate->ref && decimate_frame(inlink->dst, cur, decimate->ref)) {
decimate->drop_count = FFMAX(1, decimate->drop_count+1);
} else {
avfilter_unref_buffer(decimate->ref);
decimate->ref = cur;
inlink->cur_buf = NULL;
decimate->drop_count = FFMIN(-1, decimate->drop_count-1);
if ((ret = ff_start_frame(outlink,
avfilter_ref_buffer(cur, ~AV_PERM_WRITE)) < 0) ||
(ret = ff_draw_slice(outlink, 0, inlink->h, 1)) < 0 ||
(ret = ff_end_frame(outlink)) < 0)
return ret;
}
av_log(inlink->dst, AV_LOG_DEBUG,
"%s pts:%s pts_time:%s drop_count:%d\n",
decimate->drop_count > 0 ? "drop" : "keep",
av_ts2str(cur->pts), av_ts2timestr(cur->pts, &inlink->time_base),
decimate->drop_count);
return 0;
}
static int request_frame(AVFilterLink *outlink)
{
DecimateContext *decimate = outlink->src->priv;
AVFilterLink *inlink = outlink->src->inputs[0];
int ret;
do {
ret = ff_request_frame(inlink);
} while (decimate->drop_count > 0 && ret >= 0);
return ret;
}
AVFilter avfilter_vf_decimate = {
.name = "decimate",
.description = NULL_IF_CONFIG_SMALL("Remove near-duplicate frames."),
.init = init,
.uninit = uninit,
.priv_size = sizeof(DecimateContext),
.query_formats = query_formats,
.inputs = (const AVFilterPad[]) {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.get_video_buffer = ff_null_get_video_buffer,
.config_props = config_input,
.start_frame = start_frame,
.draw_slice = draw_slice,
.end_frame = end_frame,
.min_perms = AV_PERM_READ | AV_PERM_PRESERVE,
},
{ .name = NULL }
},
.outputs = (const AVFilterPad[]) {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.request_frame = request_frame,
},
{ .name = NULL }
},
};
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