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 "libavutil/video_enc_params.h"
27
28 #include "avfilter.h"
29 #include "formats.h"
30 #include "internal.h"
31 #include "video.h"
32
33 typedef struct QPContext {
34 const AVClass *class;
35 char *qp_expr_str;
36 int8_t lut[257];
37 int h, qstride;
38 int evaluate_per_mb;
39 } QPContext;
40
41 static const char *const var_names[] = { "known", "qp", "x", "y", "w", "h", NULL };
42
43 #define OFFSET(x) offsetof(QPContext, x)
44 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
45
46 static const AVOption qp_options[] = {
47 { "qp", "set qp expression", OFFSET(qp_expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
48 { NULL }
49 };
50
51 AVFILTER_DEFINE_CLASS(qp);
52
config_input(AVFilterLink * inlink)53 static int config_input(AVFilterLink *inlink)
54 {
55 AVFilterContext *ctx = inlink->dst;
56 QPContext *s = ctx->priv;
57 int i;
58 int ret;
59 AVExpr *e = NULL;
60
61 if (!s->qp_expr_str)
62 return 0;
63
64 ret = av_expr_parse(&e, s->qp_expr_str, var_names, NULL, NULL, NULL, NULL, 0, ctx);
65 if (ret < 0)
66 return ret;
67
68 s->h = (inlink->h + 15) >> 4;
69 s->qstride = (inlink->w + 15) >> 4;
70 for (i = -129; i < 128; i++) {
71 double var_values[] = { i != -129, i, NAN, NAN, s->qstride, s->h, 0};
72 double temp_val = av_expr_eval(e, var_values, NULL);
73
74 if (isnan(temp_val)) {
75 if(strchr(s->qp_expr_str, 'x') || strchr(s->qp_expr_str, 'y'))
76 s->evaluate_per_mb = 1;
77 else {
78 av_expr_free(e);
79 return AVERROR(EINVAL);
80 }
81 }
82
83 s->lut[i + 129] = lrintf(temp_val);
84 }
85 av_expr_free(e);
86
87 return 0;
88 }
89
filter_frame(AVFilterLink * inlink,AVFrame * in)90 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
91 {
92 AVFilterContext *ctx = inlink->dst;
93 AVFilterLink *outlink = ctx->outputs[0];
94 QPContext *s = ctx->priv;
95 AVFrame *out = NULL;
96 int ret;
97
98 AVFrameSideData *sd_in;
99 AVVideoEncParams *par_in = NULL;
100 int8_t in_qp_global = 0;
101
102 AVVideoEncParams *par_out;
103
104 if (!s->qp_expr_str || ctx->is_disabled)
105 return ff_filter_frame(outlink, in);
106
107 sd_in = av_frame_get_side_data(in, AV_FRAME_DATA_VIDEO_ENC_PARAMS);
108 if (sd_in && sd_in->size >= sizeof(AVVideoEncParams)) {
109 par_in = (AVVideoEncParams*)sd_in->data;
110
111 // we accept the input QP table only if it is of the MPEG2 type
112 // and contains either no blocks at all or 16x16 macroblocks
113 if (par_in->type == AV_VIDEO_ENC_PARAMS_MPEG2 &&
114 (par_in->nb_blocks == s->h * s->qstride || !par_in->nb_blocks)) {
115 in_qp_global = par_in->qp;
116 if (!par_in->nb_blocks)
117 par_in = NULL;
118 } else
119 par_in = NULL;
120 }
121
122 out = av_frame_clone(in);
123 if (!out) {
124 ret = AVERROR(ENOMEM);
125 goto fail;
126 }
127
128 par_out = av_video_enc_params_create_side_data(out, AV_VIDEO_ENC_PARAMS_MPEG2,
129 (s->evaluate_per_mb || sd_in) ?
130 s->h * s->qstride : 0);
131 if (!par_out) {
132 ret = AVERROR(ENOMEM);
133 goto fail;
134 }
135
136 #define BLOCK_QP_DELTA(block_idx) \
137 (par_in ? av_video_enc_params_block(par_in, block_idx)->delta_qp : 0)
138
139 if (s->evaluate_per_mb) {
140 int y, x;
141
142 for (y = 0; y < s->h; y++)
143 for (x = 0; x < s->qstride; x++) {
144 unsigned int block_idx = y * s->qstride + x;
145 AVVideoBlockParams *b = av_video_enc_params_block(par_out, block_idx);
146 int qp = sd_in ? in_qp_global + BLOCK_QP_DELTA(block_idx) : NAN;
147 double var_values[] = { !!sd_in, qp, x, y, s->qstride, s->h, 0};
148 double temp_val;
149
150 ret = av_expr_parse_and_eval(&temp_val, s->qp_expr_str,
151 var_names, var_values,
152 NULL, NULL, NULL, NULL, 0, 0, ctx);
153 if (ret < 0)
154 goto fail;
155 b->delta_qp = lrintf(temp_val);
156 }
157 } else if (sd_in) {
158 int y, x;
159
160 for (y = 0; y < s->h; y++)
161 for (x = 0; x < s->qstride; x++) {
162 unsigned int block_idx = y * s->qstride + x;
163 AVVideoBlockParams *b = av_video_enc_params_block(par_out, block_idx);
164 b->delta_qp = s->lut[129 + (int8_t)(in_qp_global + BLOCK_QP_DELTA(block_idx))];
165 }
166 } else {
167 par_out->qp = s->lut[0];
168 }
169
170 ret = ff_filter_frame(outlink, out);
171 out = NULL;
172 fail:
173 av_frame_free(&in);
174 av_frame_free(&out);
175 return ret;
176 }
177
178 static const AVFilterPad qp_inputs[] = {
179 {
180 .name = "default",
181 .type = AVMEDIA_TYPE_VIDEO,
182 .filter_frame = filter_frame,
183 .config_props = config_input,
184 },
185 };
186
187 static const AVFilterPad qp_outputs[] = {
188 {
189 .name = "default",
190 .type = AVMEDIA_TYPE_VIDEO,
191 },
192 };
193
194 const AVFilter ff_vf_qp = {
195 .name = "qp",
196 .description = NULL_IF_CONFIG_SMALL("Change video quantization parameters."),
197 .priv_size = sizeof(QPContext),
198 FILTER_INPUTS(qp_inputs),
199 FILTER_OUTPUTS(qp_outputs),
200 .priv_class = &qp_class,
201 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL |
202 AVFILTER_FLAG_METADATA_ONLY,
203 };
204