Passing an explicit filename to this command is only necessary if the
documentation in the @file block refers to a file different from the
one the block resides in.
Originally committed as revision 22921 to svn://svn.ffmpeg.org/ffmpeg/trunk
reference must be 3 because both "fields" are used as reference,
and buffer_hints must include readable since we might memcpy from the old frame.
Originally committed as revision 20923 to svn://svn.ffmpeg.org/ffmpeg/trunk