This is a M64 Editor I made some months ago to simplify my life and avoid doing hexediting while TASing N64 games. Nahoc told me to share with you all so here it is! hehe.
The tool is quite simple, after loading a .m64 file, it lets you change some of the basic data such as framecount (VI/s), description, title or rerecords.
Then it lets you watch the input of each frame of a TAS file, and modify it.
Finally I added a Replacement part, useful when you are working on a TAS with different files, and you want to merge them in one. I used this when building the Super Mario 64 "120 stars" TAS for example, adding single stars to the final project.
x32 version:
http://dl.dropbox.com/u/102137768/M64%20Editor%20x32.exe
x64 version:
http://dl.dropbox.com/u/102137768/M64%20Editor%20x64.exe
(Your antivirus may detect this file as a virus or something, since it's an .exe file created with Visual Studio, but it's not a virus.)