1 /*
2 * copyright (c) 2006 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 <stdlib.h>
22
23 #include "bsf.h"
24 #include "bsf_internal.h"
25
26 #include "libavutil/log.h"
27 #include "libavutil/opt.h"
28 #include "libavutil/eval.h"
29
30 static const char *const var_names[] = {
31 "n", /// packet index, starting from zero
32 "tb", /// timebase
33 "pts", /// packet presentation timestamp
34 "dts", /// packet decoding timestamp
35 "nopts", /// AV_NOPTS_VALUE
36 "startpts", /// first seen non-AV_NOPTS_VALUE packet timestamp
37 "startdts", /// first seen non-AV_NOPTS_VALUE packet timestamp
38 "duration", "d", /// packet duration
39 "pos", /// original position of packet in its source
40 "size", /// packet size
41 "key" , /// packet keyframe flag
42 "state", /// random-ish state
43 NULL
44 };
45
46 enum var_name {
47 VAR_N,
48 VAR_TB,
49 VAR_PTS,
50 VAR_DTS,
51 VAR_NOPTS,
52 VAR_STARTPTS,
53 VAR_STARTDTS,
54 VAR_DURATION, VAR_D,
55 VAR_POS,
56 VAR_SIZE,
57 VAR_KEY,
58 VAR_STATE,
59 VAR_VARS_NB
60 };
61
62 typedef struct NoiseContext {
63 const AVClass *class;
64
65 char *amount_str;
66 char *drop_str;
67 int dropamount;
68
69 AVExpr *amount_pexpr;
70 AVExpr *drop_pexpr;
71
72 double var_values[VAR_VARS_NB];
73
74 unsigned int state;
75 unsigned int pkt_idx;
76 } NoiseContext;
77
noise_init(AVBSFContext * ctx)78 static int noise_init(AVBSFContext *ctx)
79 {
80 NoiseContext *s = ctx->priv_data;
81 int ret;
82
83 if (!s->amount_str) {
84 s->amount_str = (!s->drop_str && !s->dropamount) ? av_strdup("-1") : av_strdup("0");
85 if (!s->amount_str)
86 return AVERROR(ENOMEM);
87 }
88
89 if (ctx->par_in->codec_id == AV_CODEC_ID_WRAPPED_AVFRAME &&
90 strcmp(s->amount_str, "0")) {
91 av_log(ctx, AV_LOG_ERROR, "Wrapped AVFrame noising is unsupported\n");
92 return AVERROR_PATCHWELCOME;
93 }
94
95 ret = av_expr_parse(&s->amount_pexpr, s->amount_str,
96 var_names, NULL, NULL, NULL, NULL, 0, ctx);
97 if (ret < 0) {
98 av_log(ctx, AV_LOG_ERROR, "Error in parsing expr for amount: %s\n", s->amount_str);
99 return ret;
100 }
101
102 if (s->drop_str && s->dropamount) {
103 av_log(ctx, AV_LOG_WARNING, "Both drop '%s' and dropamount=%d set. Ignoring dropamount.\n",
104 s->drop_str, s->dropamount);
105 s->dropamount = 0;
106 }
107
108 if (s->drop_str) {
109 ret = av_expr_parse(&s->drop_pexpr, s->drop_str,
110 var_names, NULL, NULL, NULL, NULL, 0, ctx);
111 if (ret < 0) {
112 av_log(ctx, AV_LOG_ERROR, "Error in parsing expr for drop: %s\n", s->drop_str);
113 return ret;
114 }
115 }
116
117 s->var_values[VAR_TB] = ctx->time_base_out.den ? av_q2d(ctx->time_base_out) : 0;
118 s->var_values[VAR_NOPTS] = AV_NOPTS_VALUE;
119 s->var_values[VAR_STARTPTS] = AV_NOPTS_VALUE;
120 s->var_values[VAR_STARTDTS] = AV_NOPTS_VALUE;
121 s->var_values[VAR_STATE] = 0;
122
123 return 0;
124 }
125
noise(AVBSFContext * ctx,AVPacket * pkt)126 static int noise(AVBSFContext *ctx, AVPacket *pkt)
127 {
128 NoiseContext *s = ctx->priv_data;
129 int i, ret, amount, drop = 0;
130 double res;
131
132 ret = ff_bsf_get_packet_ref(ctx, pkt);
133 if (ret < 0)
134 return ret;
135
136 s->var_values[VAR_N] = s->pkt_idx++;
137 s->var_values[VAR_PTS] = pkt->pts;
138 s->var_values[VAR_DTS] = pkt->dts;
139 s->var_values[VAR_DURATION] =
140 s->var_values[VAR_D] = pkt->duration;
141 s->var_values[VAR_SIZE] = pkt->size;
142 s->var_values[VAR_KEY] = !!(pkt->flags & AV_PKT_FLAG_KEY);
143 s->var_values[VAR_POS] = pkt->pos;
144
145 if (s->var_values[VAR_STARTPTS] == AV_NOPTS_VALUE)
146 s->var_values[VAR_STARTPTS] = pkt->pts;
147
148 if (s->var_values[VAR_STARTDTS] == AV_NOPTS_VALUE)
149 s->var_values[VAR_STARTDTS] = pkt->dts;
150
151 res = av_expr_eval(s->amount_pexpr, s->var_values, NULL);
152
153 if (isnan(res))
154 amount = 0;
155 else if (res < 0)
156 amount = (s->state % 10001 + 1);
157 else
158 amount = (int)res;
159
160 if (s->drop_str) {
161 res = av_expr_eval(s->drop_pexpr, s->var_values, NULL);
162
163 if (isnan(res))
164 drop = 0;
165 else if (res < 0)
166 drop = !(s->state % FFABS((int)res));
167 else
168 drop = !!res;
169 }
170
171 if(s->dropamount) {
172 drop = !(s->state % s->dropamount);
173 }
174
175 av_log(ctx, AV_LOG_VERBOSE, "Stream #%d packet %d pts %"PRId64" - amount %d drop %d\n",
176 pkt->stream_index, (unsigned int)s->var_values[VAR_N], pkt->pts, amount, drop);
177
178 if (drop) {
179 s->var_values[VAR_STATE] = ++s->state;
180 av_packet_unref(pkt);
181 return AVERROR(EAGAIN);
182 }
183
184 if (amount) {
185 ret = av_packet_make_writable(pkt);
186 if (ret < 0) {
187 av_packet_unref(pkt);
188 return ret;
189 }
190 }
191
192 for (i = 0; i < pkt->size; i++) {
193 s->state += pkt->data[i] + 1;
194 if (amount && s->state % amount == 0)
195 pkt->data[i] = s->state;
196 }
197
198 s->var_values[VAR_STATE] = s->state;
199
200 return 0;
201 }
202
noise_close(AVBSFContext * bsf)203 static void noise_close(AVBSFContext *bsf)
204 {
205 NoiseContext *s = bsf->priv_data;
206
207 av_expr_free(s->amount_pexpr);
208 av_expr_free(s->drop_pexpr);
209 s->amount_pexpr = s->drop_pexpr = NULL;
210 }
211
212 #define OFFSET(x) offsetof(NoiseContext, x)
213 #define FLAGS (AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_BSF_PARAM)
214 static const AVOption options[] = {
215 { "amount", NULL, OFFSET(amount_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, FLAGS },
216 { "drop", NULL, OFFSET(drop_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, FLAGS },
217 { "dropamount", NULL, OFFSET(dropamount), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS },
218 { NULL },
219 };
220
221 static const AVClass noise_class = {
222 .class_name = "noise",
223 .item_name = av_default_item_name,
224 .option = options,
225 .version = LIBAVUTIL_VERSION_INT,
226 };
227
228 const FFBitStreamFilter ff_noise_bsf = {
229 .p.name = "noise",
230 .p.priv_class = &noise_class,
231 .priv_data_size = sizeof(NoiseContext),
232 .init = noise_init,
233 .close = noise_close,
234 .filter = noise,
235 };
236