1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
|
/*
* copyright (c) 2006 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 <stdlib.h>
#include "bsf.h"
#include "bsf_internal.h"
#include "libavutil/avstring.h"
#include "libavutil/log.h"
#include "libavutil/opt.h"
#include "libavutil/eval.h"
static const char *const var_names[] = {
"n", /// packet index, starting from zero
"tb", /// timebase
"pts", /// packet presentation timestamp
"dts", /// packet decoding timestamp
"nopts", /// AV_NOPTS_VALUE
"startpts", /// first seen non-AV_NOPTS_VALUE packet timestamp
"startdts", /// first seen non-AV_NOPTS_VALUE packet timestamp
"duration", "d", /// packet duration
"pos", /// original position of packet in its source
"size", /// packet size
"key" , /// packet keyframe flag
"state", /// random-ish state
NULL
};
enum var_name {
VAR_N,
VAR_TB,
VAR_PTS,
VAR_DTS,
VAR_NOPTS,
VAR_STARTPTS,
VAR_STARTDTS,
VAR_DURATION, VAR_D,
VAR_POS,
VAR_SIZE,
VAR_KEY,
VAR_STATE,
VAR_VARS_NB
};
typedef struct NoiseContext {
const AVClass *class;
char *amount_str;
char *drop_str;
int dropamount;
AVExpr *amount_pexpr;
AVExpr *drop_pexpr;
double var_values[VAR_VARS_NB];
unsigned int state;
unsigned int pkt_idx;
} NoiseContext;
static int noise_init(AVBSFContext *ctx)
{
NoiseContext *s = ctx->priv_data;
int ret;
if (!s->amount_str) {
s->amount_str = (!s->drop_str && !s->dropamount) ? av_strdup("-1") : av_strdup("0");
if (!s->amount_str)
return AVERROR(ENOMEM);
}
ret = av_expr_parse(&s->amount_pexpr, s->amount_str,
var_names, NULL, NULL, NULL, NULL, 0, ctx);
if (ret < 0) {
av_log(ctx, AV_LOG_ERROR, "Error in parsing expr for amount: %s\n", s->amount_str);
return ret;
}
if (s->drop_str && s->dropamount) {
av_log(ctx, AV_LOG_WARNING, "Both drop '%s' and dropamount=%d set. Ignoring dropamount.\n",
s->drop_str, s->dropamount);
s->dropamount = 0;
}
if (s->drop_str) {
ret = av_expr_parse(&s->drop_pexpr, s->drop_str,
var_names, NULL, NULL, NULL, NULL, 0, ctx);
if (ret < 0) {
av_log(ctx, AV_LOG_ERROR, "Error in parsing expr for drop: %s\n", s->drop_str);
return ret;
}
}
s->var_values[VAR_TB] = ctx->time_base_out.den ? av_q2d(ctx->time_base_out) : 0;
s->var_values[VAR_NOPTS] = AV_NOPTS_VALUE;
s->var_values[VAR_STARTPTS] = AV_NOPTS_VALUE;
s->var_values[VAR_STARTDTS] = AV_NOPTS_VALUE;
s->var_values[VAR_STATE] = 0;
return 0;
}
static int noise(AVBSFContext *ctx, AVPacket *pkt)
{
NoiseContext *s = ctx->priv_data;
int i, ret, amount, drop = 0;
double res;
ret = ff_bsf_get_packet_ref(ctx, pkt);
if (ret < 0)
return ret;
s->var_values[VAR_N] = s->pkt_idx++;
s->var_values[VAR_PTS] = pkt->pts;
s->var_values[VAR_DTS] = pkt->dts;
s->var_values[VAR_DURATION] =
s->var_values[VAR_D] = pkt->duration;
s->var_values[VAR_SIZE] = pkt->size;
s->var_values[VAR_KEY] = !!(pkt->flags & AV_PKT_FLAG_KEY);
s->var_values[VAR_POS] = pkt->pos;
if (s->var_values[VAR_STARTPTS] == AV_NOPTS_VALUE)
s->var_values[VAR_STARTPTS] = pkt->pts;
if (s->var_values[VAR_STARTDTS] == AV_NOPTS_VALUE)
s->var_values[VAR_STARTDTS] = pkt->dts;
res = av_expr_eval(s->amount_pexpr, s->var_values, NULL);
if (isnan(res))
amount = 0;
else if (res < 0)
amount = (s->state % 10001 + 1);
else
amount = (int)res;
if (s->drop_str) {
res = av_expr_eval(s->drop_pexpr, s->var_values, NULL);
if (isnan(res))
drop = 0;
else if (res < 0)
drop = !(s->state % FFABS((int)res));
else
drop = !!res;
}
if(s->dropamount) {
drop = !(s->state % s->dropamount);
}
av_log(ctx, AV_LOG_VERBOSE, "Stream #%d packet %d pts %"PRId64" - amount %d drop %d\n",
pkt->stream_index, (unsigned int)s->var_values[VAR_N], pkt->pts, amount, drop);
if (drop) {
s->var_values[VAR_STATE] = ++s->state;
av_packet_unref(pkt);
return AVERROR(EAGAIN);
}
if (amount) {
ret = av_packet_make_writable(pkt);
if (ret < 0) {
av_packet_unref(pkt);
return ret;
}
}
for (i = 0; i < pkt->size; i++) {
s->state += pkt->data[i] + 1;
if (amount && s->state % amount == 0)
pkt->data[i] = s->state;
}
s->var_values[VAR_STATE] = s->state;
return 0;
}
static void noise_close(AVBSFContext *bsf)
{
NoiseContext *s = bsf->priv_data;
av_expr_free(s->amount_pexpr);
av_expr_free(s->drop_pexpr);
s->amount_pexpr = s->drop_pexpr = NULL;
}
#define OFFSET(x) offsetof(NoiseContext, x)
#define FLAGS (AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_BSF_PARAM)
static const AVOption options[] = {
{ "amount", NULL, OFFSET(amount_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, FLAGS },
{ "drop", NULL, OFFSET(drop_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, FLAGS },
{ "dropamount", NULL, OFFSET(dropamount), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS },
{ NULL },
};
static const AVClass noise_class = {
.class_name = "noise",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
const AVBitStreamFilter ff_noise_bsf = {
.name = "noise",
.priv_data_size = sizeof(NoiseContext),
.priv_class = &noise_class,
.init = noise_init,
.close = noise_close,
.filter = noise,
};
|
