I am tired of making useless and hardly useful tools, so I made last one as advanced version of vbm/smv convertors combined in one.
It's command-line program for windows and linux used to do easy editing movie file editing without having to look into hex code and file format description.
tashex -t <movie filename>
converts any supported movie to text files: header file and controller files
header file contains list of controller files and some data you won't need to change.
controller files have all controller (and FDS for hes movies) data in pretty understandable format - every line has frame number and keys pressed during that frame. Frame number us not used when file is converted from text to movie, it's only for your reference, you may move frames around, only data matters, one line = one frame (except lines starting with $ which are FDS data for next frame) you can add ":number" at the end of line to duplicate frame, where number is number of frames for this input to last.
tashex -c <text header filename>
converts set of text files back into the movie
tashex -d <filehame> <x> <l>
deletes L frames starting from one numbered X (first frame has number 0)
tashex -r <fn1> <x1> <x2> <fn2> <x3> <x4>
it accomplishes main task of hexediting - replaces part of movie 1 with part of movie 2. frames x1-x2 in file 1 are replaced with frames x3-x4 from second file.
also little bit of scripting is supported, red readme.txt for more.
here it is, archive with both linux and windows versions:
http://www.savefile.com/files/627545
hope you like it... I'll find better place for it later~
EDIT: fixed issue with last bit