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f_perms.c
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1 /*
2  * Copyright (c) 2013 Clément Bœsch
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 "libavutil/lfg.h"
22 #include "libavutil/opt.h"
23 #include "libavutil/random_seed.h"
24 #include "audio.h"
25 #include "video.h"
26 
27 enum mode {
34 };
35 
36 typedef struct {
37  const AVClass *class;
39  int64_t random_seed;
40  enum mode mode;
41 } PermsContext;
42 
43 #define OFFSET(x) offsetof(PermsContext, x)
44 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_VIDEO_PARAM
45 
46 static const AVOption options[] = {
47  { "mode", "select permissions mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64 = MODE_NONE}, MODE_NONE, NB_MODES-1, FLAGS, "mode" },
48  { "none", "do nothing", 0, AV_OPT_TYPE_CONST, {.i64 = MODE_NONE}, INT_MIN, INT_MAX, FLAGS, "mode" },
49  { "ro", "set all output frames read-only", 0, AV_OPT_TYPE_CONST, {.i64 = MODE_RO}, INT_MIN, INT_MAX, FLAGS, "mode" },
50  { "rw", "set all output frames writable", 0, AV_OPT_TYPE_CONST, {.i64 = MODE_RW}, INT_MIN, INT_MAX, FLAGS, "mode" },
51  { "toggle", "switch permissions", 0, AV_OPT_TYPE_CONST, {.i64 = MODE_TOGGLE}, INT_MIN, INT_MAX, FLAGS, "mode" },
52  { "random", "set permissions randomly", 0, AV_OPT_TYPE_CONST, {.i64 = MODE_RANDOM}, INT_MIN, INT_MAX, FLAGS, "mode" },
53  { "seed", "set the seed for the random mode", OFFSET(random_seed), AV_OPT_TYPE_INT64, {.i64 = -1}, -1, UINT32_MAX, FLAGS },
54  { NULL }
55 };
56 
57 static av_cold int init(AVFilterContext *ctx)
58 {
59  PermsContext *perms = ctx->priv;
60 
61  if (perms->mode == MODE_RANDOM) {
62  uint32_t seed;
63 
64  if (perms->random_seed == -1)
66  seed = perms->random_seed;
67  av_log(ctx, AV_LOG_INFO, "random seed: 0x%08x\n", seed);
68  av_lfg_init(&perms->lfg, seed);
69  }
70 
71  return 0;
72 }
73 
74 enum perm { RO, RW };
75 static const char *perm_str[2] = { "RO", "RW" };
76 
77 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
78 {
79  int ret;
80  AVFilterContext *ctx = inlink->dst;
81  PermsContext *perms = ctx->priv;
82  AVFrame *out = frame;
83  enum perm in_perm = av_frame_is_writable(frame) ? RW : RO;
84  enum perm out_perm;
85 
86  switch (perms->mode) {
87  case MODE_TOGGLE: out_perm = in_perm == RO ? RW : RO; break;
88  case MODE_RANDOM: out_perm = av_lfg_get(&perms->lfg) & 1 ? RW : RO; break;
89  case MODE_RO: out_perm = RO; break;
90  case MODE_RW: out_perm = RW; break;
91  default: out_perm = in_perm; break;
92  }
93 
94  av_log(ctx, AV_LOG_VERBOSE, "%s -> %s%s\n",
95  perm_str[in_perm], perm_str[out_perm],
96  in_perm == out_perm ? " (no-op)" : "");
97 
98  if (in_perm == RO && out_perm == RW) {
99  if ((ret = av_frame_make_writable(frame)) < 0)
100  return ret;
101  } else if (in_perm == RW && out_perm == RO) {
102  out = av_frame_clone(frame);
103  if (!out)
104  return AVERROR(ENOMEM);
105  }
106 
107  ret = ff_filter_frame(ctx->outputs[0], out);
108 
109  if (in_perm == RW && out_perm == RO)
110  av_frame_free(&frame);
111  return ret;
112 }
113 
114 #if CONFIG_APERMS_FILTER
115 
116 #define aperms_options options
117 AVFILTER_DEFINE_CLASS(aperms);
118 
119 static const AVFilterPad aperms_inputs[] = {
120  {
121  .name = "default",
122  .type = AVMEDIA_TYPE_AUDIO,
123  .filter_frame = filter_frame,
124  },
125  { NULL }
126 };
127 
128 static const AVFilterPad aperms_outputs[] = {
129  {
130  .name = "default",
131  .type = AVMEDIA_TYPE_AUDIO,
132  },
133  { NULL }
134 };
135 
136 AVFilter avfilter_af_aperms = {
137  .name = "aperms",
138  .description = NULL_IF_CONFIG_SMALL("Set permissions for the output audio frame."),
139  .init = init,
140  .priv_size = sizeof(PermsContext),
141  .inputs = aperms_inputs,
142  .outputs = aperms_outputs,
143  .priv_class = &aperms_class,
144 };
145 #endif /* CONFIG_APERMS_FILTER */
146 
147 #if CONFIG_PERMS_FILTER
148 
149 #define perms_options options
150 AVFILTER_DEFINE_CLASS(perms);
151 
152 static const AVFilterPad perms_inputs[] = {
153  {
154  .name = "default",
155  .type = AVMEDIA_TYPE_VIDEO,
156  .filter_frame = filter_frame,
157  },
158  { NULL }
159 };
160 
161 static const AVFilterPad perms_outputs[] = {
162  {
163  .name = "default",
164  .type = AVMEDIA_TYPE_VIDEO,
165  },
166  { NULL }
167 };
168 
169 AVFilter avfilter_vf_perms = {
170  .name = "perms",
171  .description = NULL_IF_CONFIG_SMALL("Set permissions for the output video frame."),
172  .init = init,
173  .priv_size = sizeof(PermsContext),
174  .inputs = perms_inputs,
175  .outputs = perms_outputs,
176  .priv_class = &perms_class,
177 };
178 #endif /* CONFIG_PERMS_FILTER */