131 lines
3.8 KiB
C
131 lines
3.8 KiB
C
/*
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* EXIF metadata parser
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* Copyright (c) 2013 Thilo Borgmann <thilo.borgmann _at_ mail.de>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* EXIF metadata parser
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* @author Thilo Borgmann <thilo.borgmann _at_ mail.de>
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*/
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#include "exif.h"
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static const char *exif_get_tag_name(uint16_t id)
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{
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int i;
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for (i = 0; i < FF_ARRAY_ELEMS(tag_list); i++) {
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if (tag_list[i].id == id)
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return tag_list[i].name;
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}
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return NULL;
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}
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static int exif_add_metadata(AVCodecContext *avctx, int count, int type,
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const char *name, const char *sep,
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GetByteContext *gb, int le,
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AVDictionary **metadata)
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{
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switch(type) {
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case TIFF_DOUBLE : return ff_tadd_doubles_metadata(count, name, sep, gb, le, metadata);
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case TIFF_SHORT : return ff_tadd_shorts_metadata(count, name, sep, gb, le, metadata);
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case TIFF_BYTE :
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case TIFF_UNDEFINED: return ff_tadd_bytes_metadata(count, name, sep, gb, le, metadata);
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case TIFF_STRING : return ff_tadd_string_metadata(count, name, gb, le, metadata);
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case TIFF_SRATIONAL:
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case TIFF_RATIONAL : return ff_tadd_rational_metadata(count, name, sep, gb, le, metadata);
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case TIFF_SLONG :
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case TIFF_LONG : return ff_tadd_long_metadata(count, name, sep, gb, le, metadata);
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default:
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avpriv_request_sample(avctx, "TIFF tag type (%u)", type);
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return 0;
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};
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}
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static int exif_decode_tag(AVCodecContext *avctx, GetByteContext *gbytes, int le,
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int depth, AVDictionary **metadata)
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{
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int ret, cur_pos;
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unsigned id, count;
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enum TiffTypes type;
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if (depth > 2) {
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return 0;
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}
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ff_tread_tag(gbytes, le, &id, &type, &count, &cur_pos);
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// read count values and add it metadata
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// store metadata or proceed with next IFD
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ret = ff_tis_ifd(id);
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if (ret) {
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ret = avpriv_exif_decode_ifd(avctx, gbytes, le, depth + 1, metadata);
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} else {
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const char *name = exif_get_tag_name(id);
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char *use_name = (char*) name;
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if (!use_name) {
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use_name = av_malloc(7);
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if (!use_name) {
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return AVERROR(ENOMEM);
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}
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snprintf(use_name, 7, "0x%04X", id);
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}
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ret = exif_add_metadata(avctx, count, type, use_name, NULL,
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gbytes, le, metadata);
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if (!name) {
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av_freep(&use_name);
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}
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}
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bytestream2_seek(gbytes, cur_pos, SEEK_SET);
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return ret;
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}
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int avpriv_exif_decode_ifd(AVCodecContext *avctx, GetByteContext *gbytes, int le,
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int depth, AVDictionary **metadata)
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{
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int i, ret;
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int entries;
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entries = ff_tget_short(gbytes, le);
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if (bytestream2_get_bytes_left(gbytes) < entries * 12) {
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return AVERROR_INVALIDDATA;
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}
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for (i = 0; i < entries; i++) {
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if ((ret = exif_decode_tag(avctx, gbytes, le, depth, metadata)) < 0) {
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return ret;
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}
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}
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// return next IDF offset or 0x000000000 or a value < 0 for failure
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return ff_tget_long(gbytes, le);
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}
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