int flags;
#define AV_OPT_FLAG_ENCODING_PARAM 1 ///< a generic parameter which can be set by the user for muxing or encoding
#define AV_OPT_FLAG_DECODING_PARAM 2 ///< a generic parameter which can be set by the user for demuxing or decoding
+#if FF_API_OPT_TYPE_METADATA
#define AV_OPT_FLAG_METADATA 4 ///< some data extracted or inserted into the file like title, comment, ...
+#endif
#define AV_OPT_FLAG_AUDIO_PARAM 8
#define AV_OPT_FLAG_VIDEO_PARAM 16
#define AV_OPT_FLAG_SUBTITLE_PARAM 32
+/**
+ * The option is inteded for exporting values to the caller.
+ */
+#define AV_OPT_FLAG_EXPORT 64
+/**
+ * The option may not be set through the AVOptions API, only read.
+ * This flag only makes sense when AV_OPT_FLAG_EXPORT is also set.
+ */
+#define AV_OPT_FLAG_READONLY 128
#define AV_OPT_FLAG_FILTERING_PARAM (1<<16) ///< a generic parameter which can be set by the user for filtering
//FIXME think about enc-audio, ... style flags