ffmpeg/doc/APIchanges

20090601 - r19025 - lavc 52.30.0 - av_lockmgr_register()
  av_lockmgr_register() can be used to register a callback function
  that lavc (and in the future, libraries that depend on lavc) can use
  to implement mutexes. The application should provide a callback function
  the implements the AV_LOCK_* operations described in avcodec.h.
  When the lock manager is registered FFmpeg is guaranteed to behave
  correct also in a multi-threaded application.

20090301 - r17682 - lavf 52.31.0 - Generic metadata API
  This version introduce a new metadata API (see av_metadata_get() and friends).
  The old API is now deprecated and shouldn't be used anymore. This especially
  include the following structure fields:
    - AVFormatContext.title
    - AVFormatContext.author
    - AVFormatContext.copyright
    - AVFormatContext.comment
    - AVFormatContext.album
    - AVFormatContext.year
    - AVFormatContext.track
    - AVFormatContext.genre
    - AVStream.language
    - AVStream.filename
    - AVProgram.provider_name
    - AVProgram.name
    - AVChapter.title