| 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 | } |