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
|
/*
* MPEG-DASH ISO BMFF segmenter
* Copyright (c) 2014 Martin Storsjo
*
* 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 "config.h"
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "libavutil/avstring.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "libavutil/rational.h"
#include "libavutil/time_internal.h"
#include "avc.h"
#include "avformat.h"
#include "avio_internal.h"
#include "internal.h"
#include "isom.h"
#include "os_support.h"
#include "url.h"
#include "dash.h"
static DASHTmplId dash_read_tmpl_id(const char *identifier, char *format_tag,
size_t format_tag_size, const char **ptr) {
const char *next_ptr;
DASHTmplId id_type = DASH_TMPL_ID_UNDEFINED;
if (av_strstart(identifier, "$$", &next_ptr)) {
id_type = DASH_TMPL_ID_ESCAPE;
*ptr = next_ptr;
} else if (av_strstart(identifier, "$RepresentationID$", &next_ptr)) {
id_type = DASH_TMPL_ID_REP_ID;
// default to basic format, as $RepresentationID$ identifiers
// are not allowed to have custom format-tags.
av_strlcpy(format_tag, "%d", format_tag_size);
*ptr = next_ptr;
} else { // the following identifiers may have an explicit format_tag
if (av_strstart(identifier, "$Number", &next_ptr))
id_type = DASH_TMPL_ID_NUMBER;
else if (av_strstart(identifier, "$Bandwidth", &next_ptr))
id_type = DASH_TMPL_ID_BANDWIDTH;
else if (av_strstart(identifier, "$Time", &next_ptr))
id_type = DASH_TMPL_ID_TIME;
else
id_type = DASH_TMPL_ID_UNDEFINED;
// next parse the dash format-tag and generate a c-string format tag
// (next_ptr now points at the first '%' at the beginning of the format-tag)
if (id_type != DASH_TMPL_ID_UNDEFINED) {
const char *number_format = (id_type == DASH_TMPL_ID_TIME) ? PRId64 : "d";
if (next_ptr[0] == '$') { // no dash format-tag
snprintf(format_tag, format_tag_size, "%%%s", number_format);
*ptr = &next_ptr[1];
} else {
const char *width_ptr;
// only tolerate single-digit width-field (i.e. up to 9-digit width)
if (av_strstart(next_ptr, "%0", &width_ptr) &&
av_isdigit(width_ptr[0]) &&
av_strstart(&width_ptr[1], "d$", &next_ptr)) {
// yes, we're using a format tag to build format_tag.
snprintf(format_tag, format_tag_size, "%s%c%s", "%0", width_ptr[0], number_format);
*ptr = next_ptr;
} else {
av_log(NULL, AV_LOG_WARNING, "Failed to parse format-tag beginning with %s. Expected either a "
"closing '$' character or a format-string like '%%0[width]d', "
"where width must be a single digit\n", next_ptr);
id_type = DASH_TMPL_ID_UNDEFINED;
}
}
}
}
return id_type;
}
void ff_dash_fill_tmpl_params(char *dst, size_t buffer_size,
const char *template, int rep_id,
int number, int bit_rate,
int64_t time) {
int dst_pos = 0;
const char *t_cur = template;
while (dst_pos < buffer_size - 1 && *t_cur) {
char format_tag[7]; // May be "%d", "%0Xd", or "%0Xlld" (for $Time$), where X is in [0-9]
int n = 0;
DASHTmplId id_type;
const char *t_next = strchr(t_cur, '$'); // copy over everything up to the first '$' character
if (t_next) {
int num_copy_bytes = FFMIN(t_next - t_cur, buffer_size - dst_pos - 1);
av_strlcpy(&dst[dst_pos], t_cur, num_copy_bytes + 1);
// advance
dst_pos += num_copy_bytes;
t_cur = t_next;
} else { // no more DASH identifiers to substitute - just copy the rest over and break
av_strlcpy(&dst[dst_pos], t_cur, buffer_size - dst_pos);
break;
}
if (dst_pos >= buffer_size - 1 || !*t_cur)
break;
// t_cur is now pointing to a '$' character
id_type = dash_read_tmpl_id(t_cur, format_tag, sizeof(format_tag), &t_next);
switch (id_type) {
case DASH_TMPL_ID_ESCAPE:
av_strlcpy(&dst[dst_pos], "$", 2);
n = 1;
break;
case DASH_TMPL_ID_REP_ID:
n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, rep_id);
break;
case DASH_TMPL_ID_NUMBER:
n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, number);
break;
case DASH_TMPL_ID_BANDWIDTH:
n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, bit_rate);
break;
case DASH_TMPL_ID_TIME:
n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, time);
break;
case DASH_TMPL_ID_UNDEFINED:
// copy over one byte and advance
av_strlcpy(&dst[dst_pos], t_cur, 2);
n = 1;
t_next = &t_cur[1];
break;
}
// t_next points just past the processed identifier
// n is the number of bytes that were attempted to be written to dst
// (may have failed to write all because buffer_size).
// advance
dst_pos += FFMIN(n, buffer_size - dst_pos - 1);
t_cur = t_next;
}
}
|
