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path: root/libavfilter/vf_qp.c (plain)
blob: 33d39493bc02f234ca229b7040f713a477949e72
1/*
2 * Copyright (C) 2004 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include <math.h>
22#include "libavutil/eval.h"
23#include "libavutil/imgutils.h"
24#include "libavutil/pixdesc.h"
25#include "libavutil/opt.h"
26#include "avfilter.h"
27#include "formats.h"
28#include "internal.h"
29#include "video.h"
30
31typedef struct QPContext {
32 const AVClass *class;
33 char *qp_expr_str;
34 int8_t lut[257];
35 int h, qstride;
36 int evaluate_per_mb;
37} QPContext;
38
39#define OFFSET(x) offsetof(QPContext, x)
40#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
41
42static const AVOption qp_options[] = {
43 { "qp", "set qp expression", OFFSET(qp_expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
44 { NULL }
45};
46
47AVFILTER_DEFINE_CLASS(qp);
48
49static int config_input(AVFilterLink *inlink)
50{
51 AVFilterContext *ctx = inlink->dst;
52 QPContext *s = ctx->priv;
53 int i;
54 int ret;
55 AVExpr *e = NULL;
56 static const char *var_names[] = { "known", "qp", "x", "y", "w", "h", NULL };
57
58 if (!s->qp_expr_str)
59 return 0;
60
61 ret = av_expr_parse(&e, s->qp_expr_str, var_names, NULL, NULL, NULL, NULL, 0, ctx);
62 if (ret < 0)
63 return ret;
64
65 s->h = (inlink->h + 15) >> 4;
66 s->qstride = (inlink->w + 15) >> 4;
67 for (i = -129; i < 128; i++) {
68 double var_values[] = { i != -129, i, NAN, NAN, s->qstride, s->h, 0};
69 double temp_val = av_expr_eval(e, var_values, NULL);
70
71 if (isnan(temp_val)) {
72 if(strchr(s->qp_expr_str, 'x') || strchr(s->qp_expr_str, 'y'))
73 s->evaluate_per_mb = 1;
74 else {
75 av_expr_free(e);
76 return AVERROR(EINVAL);
77 }
78 }
79
80 s->lut[i + 129] = lrintf(temp_val);
81 }
82 av_expr_free(e);
83
84 return 0;
85}
86
87static int filter_frame(AVFilterLink *inlink, AVFrame *in)
88{
89 AVFilterContext *ctx = inlink->dst;
90 AVFilterLink *outlink = ctx->outputs[0];
91 QPContext *s = ctx->priv;
92 AVBufferRef *out_qp_table_buf;
93 AVFrame *out = NULL;
94 const int8_t *in_qp_table;
95 int type, stride, ret;
96
97 if (!s->qp_expr_str || ctx->is_disabled)
98 return ff_filter_frame(outlink, in);
99
100 out_qp_table_buf = av_buffer_alloc(s->h * s->qstride);
101 if (!out_qp_table_buf) {
102 ret = AVERROR(ENOMEM);
103 goto fail;
104 }
105
106 out = av_frame_clone(in);
107 if (!out) {
108 av_buffer_unref(&out_qp_table_buf);
109 ret = AVERROR(ENOMEM);
110 goto fail;
111 }
112
113 in_qp_table = av_frame_get_qp_table(in, &stride, &type);
114 av_frame_set_qp_table(out, out_qp_table_buf, s->qstride, type);
115
116
117 if (s->evaluate_per_mb) {
118 int y, x;
119
120 for (y = 0; y < s->h; y++)
121 for (x = 0; x < s->qstride; x++) {
122 int qp = in_qp_table ? in_qp_table[x + stride * y] : NAN;
123 double var_values[] = { !!in_qp_table, qp, x, y, s->qstride, s->h, 0};
124 static const char *var_names[] = { "known", "qp", "x", "y", "w", "h", NULL };
125 double temp_val;
126
127 ret = av_expr_parse_and_eval(&temp_val, s->qp_expr_str,
128 var_names, var_values,
129 NULL, NULL, NULL, NULL, 0, 0, ctx);
130 if (ret < 0)
131 goto fail;
132 out_qp_table_buf->data[x + s->qstride * y] = lrintf(temp_val);
133 }
134 } else if (in_qp_table) {
135 int y, x;
136
137 for (y = 0; y < s->h; y++)
138 for (x = 0; x < s->qstride; x++)
139 out_qp_table_buf->data[x + s->qstride * y] = s->lut[129 +
140 ((int8_t)in_qp_table[x + stride * y])];
141 } else {
142 int y, x, qp = s->lut[0];
143
144 for (y = 0; y < s->h; y++)
145 for (x = 0; x < s->qstride; x++)
146 out_qp_table_buf->data[x + s->qstride * y] = qp;
147 }
148
149 ret = ff_filter_frame(outlink, out);
150 out = NULL;
151fail:
152 av_frame_free(&in);
153 av_frame_free(&out);
154 return ret;
155}
156
157static const AVFilterPad qp_inputs[] = {
158 {
159 .name = "default",
160 .type = AVMEDIA_TYPE_VIDEO,
161 .filter_frame = filter_frame,
162 .config_props = config_input,
163 },
164 { NULL }
165};
166
167static const AVFilterPad qp_outputs[] = {
168 {
169 .name = "default",
170 .type = AVMEDIA_TYPE_VIDEO,
171 },
172 { NULL }
173};
174
175AVFilter ff_vf_qp = {
176 .name = "qp",
177 .description = NULL_IF_CONFIG_SMALL("Change video quantization parameters."),
178 .priv_size = sizeof(QPContext),
179 .inputs = qp_inputs,
180 .outputs = qp_outputs,
181 .priv_class = &qp_class,
182 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,
183};
184
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