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-rw-r--r--libavcodec/exif.c142
1 files changed, 142 insertions, 0 deletions
diff --git a/libavcodec/exif.c b/libavcodec/exif.c
new file mode 100644
index 0000000000..fa30f0573f
--- /dev/null
+++ b/libavcodec/exif.c
@@ -0,0 +1,142 @@
+/*
+ * EXIF metadata parser
+ * Copyright (c) 2013 Thilo Borgmann <thilo.borgmann _at_ mail.de>
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * EXIF metadata parser
+ * @author Thilo Borgmann <thilo.borgmann _at_ mail.de>
+ */
+
+#include "exif.h"
+
+
+static const char *exif_get_tag_name(uint16_t id)
+{
+ int i;
+
+ for (i = 0; i < FF_ARRAY_ELEMS(tag_list); i++) {
+ if (tag_list[i].id == id)
+ return tag_list[i].name;
+ }
+
+ return NULL;
+}
+
+
+static int exif_add_metadata(AVCodecContext *avctx, int count, int type,
+ const char *name, const char *sep,
+ GetByteContext *gb, int le,
+ AVDictionary **metadata)
+{
+ switch(type) {
+ case 0:
+ av_log(avctx, AV_LOG_WARNING,
+ "Invalid TIFF tag type 0 found for %s with size %d\n",
+ name, count);
+ return 0;
+ case TIFF_DOUBLE : return ff_tadd_doubles_metadata(count, name, sep, gb, le, metadata);
+ case TIFF_SSHORT : return ff_tadd_shorts_metadata(count, name, sep, gb, le, 1, metadata);
+ case TIFF_SHORT : return ff_tadd_shorts_metadata(count, name, sep, gb, le, 0, metadata);
+ case TIFF_SBYTE : return ff_tadd_bytes_metadata(count, name, sep, gb, le, 1, metadata);
+ case TIFF_BYTE :
+ case TIFF_UNDEFINED: return ff_tadd_bytes_metadata(count, name, sep, gb, le, 0, metadata);
+ case TIFF_STRING : return ff_tadd_string_metadata(count, name, gb, le, metadata);
+ case TIFF_SRATIONAL:
+ case TIFF_RATIONAL : return ff_tadd_rational_metadata(count, name, sep, gb, le, metadata);
+ case TIFF_SLONG :
+ case TIFF_LONG : return ff_tadd_long_metadata(count, name, sep, gb, le, metadata);
+ default:
+ avpriv_request_sample(avctx, "TIFF tag type (%u)", type);
+ return 0;
+ };
+}
+
+
+static int exif_decode_tag(AVCodecContext *avctx, GetByteContext *gbytes, int le,
+ int depth, AVDictionary **metadata)
+{
+ int ret, cur_pos;
+ unsigned id, count;
+ enum TiffTypes type;
+
+ if (depth > 2) {
+ return 0;
+ }
+
+ ff_tread_tag(gbytes, le, &id, &type, &count, &cur_pos);
+
+ if (!bytestream2_tell(gbytes)) {
+ bytestream2_seek(gbytes, cur_pos, SEEK_SET);
+ return 0;
+ }
+
+ // read count values and add it metadata
+ // store metadata or proceed with next IFD
+ ret = ff_tis_ifd(id);
+ if (ret) {
+ ret = avpriv_exif_decode_ifd(avctx, gbytes, le, depth + 1, metadata);
+ } else {
+ const char *name = exif_get_tag_name(id);
+ char *use_name = (char*) name;
+
+ if (!use_name) {
+ use_name = av_malloc(7);
+ if (!use_name) {
+ return AVERROR(ENOMEM);
+ }
+ snprintf(use_name, 7, "0x%04X", id);
+ }
+
+ ret = exif_add_metadata(avctx, count, type, use_name, NULL,
+ gbytes, le, metadata);
+
+ if (!name) {
+ av_freep(&use_name);
+ }
+ }
+
+ bytestream2_seek(gbytes, cur_pos, SEEK_SET);
+
+ return ret;
+}
+
+
+int avpriv_exif_decode_ifd(AVCodecContext *avctx, GetByteContext *gbytes, int le,
+ int depth, AVDictionary **metadata)
+{
+ int i, ret;
+ int entries;
+
+ entries = ff_tget_short(gbytes, le);
+
+ if (bytestream2_get_bytes_left(gbytes) < entries * 12) {
+ return AVERROR_INVALIDDATA;
+ }
+
+ for (i = 0; i < entries; i++) {
+ if ((ret = exif_decode_tag(avctx, gbytes, le, depth, metadata)) < 0) {
+ return ret;
+ }
+ }
+
+ // return next IDF offset or 0x000000000 or a value < 0 for failure
+ return ff_tget_long(gbytes, le);
+}