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1 | /* |
2 | * EXIF metadata parser | |
3 | * Copyright (c) 2013 Thilo Borgmann <thilo.borgmann _at_ mail.de> | |
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 | /** | |
23 | * @file | |
24 | * EXIF metadata parser | |
25 | * @author Thilo Borgmann <thilo.borgmann _at_ mail.de> | |
26 | */ | |
27 | ||
28 | #include "exif.h" | |
29 | ||
30 | ||
31 | static const char *exif_get_tag_name(uint16_t id) | |
32 | { | |
33 | int i; | |
34 | ||
35 | for (i = 0; i < FF_ARRAY_ELEMS(tag_list); i++) { | |
36 | if (tag_list[i].id == id) | |
37 | return tag_list[i].name; | |
38 | } | |
39 | ||
40 | return NULL; | |
41 | } | |
42 | ||
43 | ||
44 | static int exif_add_metadata(AVCodecContext *avctx, int count, int type, | |
45 | const char *name, const char *sep, | |
46 | GetByteContext *gb, int le, | |
47 | AVDictionary **metadata) | |
48 | { | |
49 | switch(type) { | |
50 | case 0: | |
51 | av_log(avctx, AV_LOG_WARNING, | |
52 | "Invalid TIFF tag type 0 found for %s with size %d\n", | |
53 | name, count); | |
54 | return 0; | |
55 | case TIFF_DOUBLE : return ff_tadd_doubles_metadata(count, name, sep, gb, le, metadata); | |
56 | case TIFF_SSHORT : return ff_tadd_shorts_metadata(count, name, sep, gb, le, 1, metadata); | |
57 | case TIFF_SHORT : return ff_tadd_shorts_metadata(count, name, sep, gb, le, 0, metadata); | |
58 | case TIFF_SBYTE : return ff_tadd_bytes_metadata(count, name, sep, gb, le, 1, metadata); | |
59 | case TIFF_BYTE : | |
60 | case TIFF_UNDEFINED: return ff_tadd_bytes_metadata(count, name, sep, gb, le, 0, metadata); | |
61 | case TIFF_STRING : return ff_tadd_string_metadata(count, name, gb, le, metadata); | |
62 | case TIFF_SRATIONAL: | |
63 | case TIFF_RATIONAL : return ff_tadd_rational_metadata(count, name, sep, gb, le, metadata); | |
64 | case TIFF_SLONG : | |
65 | case TIFF_LONG : return ff_tadd_long_metadata(count, name, sep, gb, le, metadata); | |
66 | default: | |
67 | avpriv_request_sample(avctx, "TIFF tag type (%u)", type); | |
68 | return 0; | |
69 | }; | |
70 | } | |
71 | ||
72 | ||
73 | static int exif_decode_tag(AVCodecContext *avctx, GetByteContext *gbytes, int le, | |
74 | int depth, AVDictionary **metadata) | |
75 | { | |
76 | int ret, cur_pos; | |
77 | unsigned id, count; | |
78 | enum TiffTypes type; | |
79 | ||
80 | if (depth > 2) { | |
81 | return 0; | |
82 | } | |
83 | ||
84 | ff_tread_tag(gbytes, le, &id, &type, &count, &cur_pos); | |
85 | ||
86 | if (!bytestream2_tell(gbytes)) { | |
87 | bytestream2_seek(gbytes, cur_pos, SEEK_SET); | |
88 | return 0; | |
89 | } | |
90 | ||
91 | // read count values and add it metadata | |
92 | // store metadata or proceed with next IFD | |
93 | ret = ff_tis_ifd(id); | |
94 | if (ret) { | |
95 | ret = avpriv_exif_decode_ifd(avctx, gbytes, le, depth + 1, metadata); | |
96 | } else { | |
97 | const char *name = exif_get_tag_name(id); | |
98 | char *use_name = (char*) name; | |
99 | ||
100 | if (!use_name) { | |
101 | use_name = av_malloc(7); | |
102 | if (!use_name) { | |
103 | return AVERROR(ENOMEM); | |
104 | } | |
105 | snprintf(use_name, 7, "0x%04X", id); | |
106 | } | |
107 | ||
108 | ret = exif_add_metadata(avctx, count, type, use_name, NULL, | |
109 | gbytes, le, metadata); | |
110 | ||
111 | if (!name) { | |
112 | av_freep(&use_name); | |
113 | } | |
114 | } | |
115 | ||
116 | bytestream2_seek(gbytes, cur_pos, SEEK_SET); | |
117 | ||
118 | return ret; | |
119 | } | |
120 | ||
121 | ||
122 | int avpriv_exif_decode_ifd(AVCodecContext *avctx, GetByteContext *gbytes, int le, | |
123 | int depth, AVDictionary **metadata) | |
124 | { | |
125 | int i, ret; | |
126 | int entries; | |
127 | ||
128 | entries = ff_tget_short(gbytes, le); | |
129 | ||
130 | if (bytestream2_get_bytes_left(gbytes) < entries * 12) { | |
131 | return AVERROR_INVALIDDATA; | |
132 | } | |
133 | ||
134 | for (i = 0; i < entries; i++) { | |
135 | if ((ret = exif_decode_tag(avctx, gbytes, le, depth, metadata)) < 0) { | |
136 | return ret; | |
137 | } | |
138 | } | |
139 | ||
140 | // return next IDF offset or 0x000000000 or a value < 0 for failure | |
141 | return ff_tget_long(gbytes, le); | |
142 | } |