Move metadata API from avcodec to avformat.

Originally committed as revision 16425 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 45 insertions, 0 deletions

diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 46e692452e..39dc4765a8 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -46,6 +46,51 @@ unsigned avformat_version(void);
 
 #include "avio.h"
 
+
+/*
+ * public Metadata API.
+ * Important concepts, to keep in mind
+ * 1. keys are unique, there are never 2 tags with equal keys, this is also
+ *    meant semantically that is a demuxer should not knowingly produce
+ *    several keys that are litterally different but semantically identical,
+ *    like key=Author5, key=Author6.
+ *    All authors have to be placed in the same tag for the case of Authors.
+ * 2. Metadata is flat, there are no subtags, if you for whatever obscene
+ *    reason want to store the email address of the child of producer alice
+ *    and actor bob, that could have key=alice_and_bobs_childs_email_address.
+ * 3. A tag whichs value is translated has the ISO 639 3-letter language code
+ *    with a '-' between appended. So for example Author-ger=Michael, Author-eng=Mike
+ *    the original/default language is in the unqualified "Author"
+ *    A demuxer should set a default if it sets any translated tag.
+ */
+
+#define AV_METADATA_IGNORE_CASE     1
+#define AV_METADATA_IGNORE_SUFFIX   2
+
+typedef struct {
+    char *key;
+    char *value;
+}AVMetaDataTag;
+
+struct AVMetaData;
+
+/**
+ * gets a metadata element with matching key.
+ * @param prev set to the previous matching element to find the next.
+ * @param flags allows case as well as suffix insensitive comparissions.
+ * @return found tag or NULL, changing key or value leads to undefined behavior.
+ */
+AVMetaDataTag *
+av_metadata_get(struct AVMetaData *m, const char *key, const AVMetaDataTag *prev, int flags);
+
+/**
+ * sets the given tag in m, overwriting an existing tag.
+ * @param tag tag to add to m, key and value will be av_strduped.
+ * @return >= 0 if success otherwise error code that is <0.
+ */
+int av_metadata_set(struct AVMetaData **m, AVMetaDataTag tag);
+
+
 /* packet functions */
 
 typedef struct AVPacket {