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/*
* Copyright (C) 2004 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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
*/
#include <math.h>
#include "libavutil/eval.h"
#include "libavutil/imgutils.h"
#include "libavutil/pixdesc.h"
#include "libavutil/opt.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
typedef struct QPContext {
const AVClass *class;
char *qp_expr_str;
int8_t lut[257];
int h, qstride;
} QPContext;
#define OFFSET(x) offsetof(QPContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption qp_options[] = {
{ "qp", "set qp expression", OFFSET(qp_expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(qp);
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
QPContext *s = ctx->priv;
int i;
int ret;
AVExpr *e = NULL;
static const char *var_names[] = { "known", "qp", NULL };
if (!s->qp_expr_str)
return 0;
ret = av_expr_parse(&e, s->qp_expr_str, var_names, NULL, NULL, NULL, NULL, 0, ctx);
if (ret < 0)
return ret;
s->h = (inlink->h + 15) >> 4;
s->qstride = (inlink->w + 15) >> 4;
for (i = -129; i < 128; i++) {
double var_values[] = { i != -129, i, 0};
double temp_val = av_expr_eval(e, var_values, NULL);
if (isnan(temp_val)) {
av_expr_free(e);
return AVERROR(EINVAL);
}
s->lut[i + 129] = lrintf(temp_val);
}
av_expr_free(e);
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
QPContext *s = ctx->priv;
AVBufferRef *out_qp_table_buf;
AVFrame *out;
const int8_t *in_qp_table;
int type, stride, ret;
if (!s->qp_expr_str || ctx->is_disabled)
return ff_filter_frame(outlink, in);
out_qp_table_buf = av_buffer_alloc(s->h * s->qstride);
if (!out_qp_table_buf) {
ret = AVERROR(ENOMEM);
goto fail;
}
out = av_frame_clone(in);
if (!out) {
av_buffer_unref(&out_qp_table_buf);
ret = AVERROR(ENOMEM);
goto fail;
}
in_qp_table = av_frame_get_qp_table(in, &stride, &type);
av_frame_set_qp_table(out, out_qp_table_buf, s->qstride, type);
if (in_qp_table) {
int y, x;
for (y = 0; y < s->h; y++)
for (x = 0; x < s->qstride; x++)
out_qp_table_buf->data[x + s->qstride * y] = s->lut[129 +
((int8_t)in_qp_table[x + stride * y])];
} else {
int y, x, qp = s->lut[0];
for (y = 0; y < s->h; y++)
for (x = 0; x < s->qstride; x++)
out_qp_table_buf->data[x + s->qstride * y] = qp;
}
ret = ff_filter_frame(outlink, out);
fail:
av_frame_free(&in);
return ret;
}
static const AVFilterPad qp_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
.config_props = config_input,
},
{ NULL }
};
static const AVFilterPad qp_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
{ NULL }
};
AVFilter ff_vf_qp = {
.name = "qp",
.description = NULL_IF_CONFIG_SMALL("Change video quantization parameters."),
.priv_size = sizeof(QPContext),
.inputs = qp_inputs,
.outputs = qp_outputs,
.priv_class = &qp_class,
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,
};
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