FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavformat/dash.c
Date: 2022-12-05 03:11:11
Exec Total Coverage
Lines: 0 68 0.0%
Functions: 0 2 0.0%
Branches: 0 39 0.0%

Line Branch Exec Source
1 /*
2 * MPEG-DASH ISO BMFF segmenter
3 * Copyright (c) 2014 Martin Storsjo
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "config.h"
23 #if HAVE_UNISTD_H
24 #include <unistd.h>
25 #endif
26
27 #include "libavutil/avstring.h"
28 #include "libavutil/intreadwrite.h"
29 #include "libavutil/mathematics.h"
30 #include "libavutil/opt.h"
31 #include "libavutil/rational.h"
32 #include "libavutil/time_internal.h"
33
34 #include "avc.h"
35 #include "avformat.h"
36 #include "avio_internal.h"
37 #include "internal.h"
38 #include "isom.h"
39 #include "os_support.h"
40 #include "url.h"
41 #include "dash.h"
42
43 static DASHTmplId dash_read_tmpl_id(const char *identifier, char *format_tag,
44 size_t format_tag_size, const char **ptr) {
45 const char *next_ptr;
46 DASHTmplId id_type = DASH_TMPL_ID_UNDEFINED;
47
48 if (av_strstart(identifier, "$$", &next_ptr)) {
49 id_type = DASH_TMPL_ID_ESCAPE;
50 *ptr = next_ptr;
51 } else if (av_strstart(identifier, "$RepresentationID$", &next_ptr)) {
52 id_type = DASH_TMPL_ID_REP_ID;
53 // default to basic format, as $RepresentationID$ identifiers
54 // are not allowed to have custom format-tags.
55 av_strlcpy(format_tag, "%d", format_tag_size);
56 *ptr = next_ptr;
57 } else { // the following identifiers may have an explicit format_tag
58 if (av_strstart(identifier, "$Number", &next_ptr))
59 id_type = DASH_TMPL_ID_NUMBER;
60 else if (av_strstart(identifier, "$Bandwidth", &next_ptr))
61 id_type = DASH_TMPL_ID_BANDWIDTH;
62 else if (av_strstart(identifier, "$Time", &next_ptr))
63 id_type = DASH_TMPL_ID_TIME;
64 else
65 id_type = DASH_TMPL_ID_UNDEFINED;
66
67 // next parse the dash format-tag and generate a c-string format tag
68 // (next_ptr now points at the first '%' at the beginning of the format-tag)
69 if (id_type != DASH_TMPL_ID_UNDEFINED) {
70 const char *number_format = (id_type == DASH_TMPL_ID_TIME) ? PRId64 : "d";
71 if (next_ptr[0] == '$') { // no dash format-tag
72 snprintf(format_tag, format_tag_size, "%%%s", number_format);
73 *ptr = &next_ptr[1];
74 } else {
75 const char *width_ptr;
76 // only tolerate single-digit width-field (i.e. up to 9-digit width)
77 if (av_strstart(next_ptr, "%0", &width_ptr) &&
78 av_isdigit(width_ptr[0]) &&
79 av_strstart(&width_ptr[1], "d$", &next_ptr)) {
80 // yes, we're using a format tag to build format_tag.
81 snprintf(format_tag, format_tag_size, "%s%c%s", "%0", width_ptr[0], number_format);
82 *ptr = next_ptr;
83 } else {
84 av_log(NULL, AV_LOG_WARNING, "Failed to parse format-tag beginning with %s. Expected either a "
85 "closing '$' character or a format-string like '%%0[width]d', "
86 "where width must be a single digit\n", next_ptr);
87 id_type = DASH_TMPL_ID_UNDEFINED;
88 }
89 }
90 }
91 }
92 return id_type;
93 }
94
95 void ff_dash_fill_tmpl_params(char *dst, size_t buffer_size,
96 const char *template, int rep_id,
97 int number, int bit_rate,
98 int64_t time) {
99 int dst_pos = 0;
100 const char *t_cur = template;
101 while (dst_pos < buffer_size - 1 && *t_cur) {
102 char format_tag[7]; // May be "%d", "%0Xd", or "%0Xlld" (for $Time$), where X is in [0-9]
103 int n = 0;
104 DASHTmplId id_type;
105 const char *t_next = strchr(t_cur, '$'); // copy over everything up to the first '$' character
106 if (t_next) {
107 int num_copy_bytes = FFMIN(t_next - t_cur, buffer_size - dst_pos - 1);
108 av_strlcpy(&dst[dst_pos], t_cur, num_copy_bytes + 1);
109 // advance
110 dst_pos += num_copy_bytes;
111 t_cur = t_next;
112 } else { // no more DASH identifiers to substitute - just copy the rest over and break
113 av_strlcpy(&dst[dst_pos], t_cur, buffer_size - dst_pos);
114 break;
115 }
116
117 if (dst_pos >= buffer_size - 1 || !*t_cur)
118 break;
119
120 // t_cur is now pointing to a '$' character
121 id_type = dash_read_tmpl_id(t_cur, format_tag, sizeof(format_tag), &t_next);
122 switch (id_type) {
123 case DASH_TMPL_ID_ESCAPE:
124 av_strlcpy(&dst[dst_pos], "$", 2);
125 n = 1;
126 break;
127 case DASH_TMPL_ID_REP_ID:
128 n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, rep_id);
129 break;
130 case DASH_TMPL_ID_NUMBER:
131 n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, number);
132 break;
133 case DASH_TMPL_ID_BANDWIDTH:
134 n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, bit_rate);
135 break;
136 case DASH_TMPL_ID_TIME:
137 n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, time);
138 break;
139 case DASH_TMPL_ID_UNDEFINED:
140 // copy over one byte and advance
141 av_strlcpy(&dst[dst_pos], t_cur, 2);
142 n = 1;
143 t_next = &t_cur[1];
144 break;
145 }
146 // t_next points just past the processed identifier
147 // n is the number of bytes that were attempted to be written to dst
148 // (may have failed to write all because buffer_size).
149
150 // advance
151 dst_pos += FFMIN(n, buffer_size - dst_pos - 1);
152 t_cur = t_next;
153 }
154 }
155
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