Hi,
i just wanted to share this.
With my Blackmagic Production Camera 4k (3840x2160) .. one of the issues is to handle files. Copy from SSD card to HD, colour correct clips, archive, etc...
I found out that a small piece of software (probably created just for the home user who wants to cut ads from a tv recording, or bulk footage from his wedding recordings) can come in very handy.

MOVAVI SPLIT MOVIE let's you cut unwanted parts of a clip and/or joining the remaining.... listen..... WITHOUT RECOMPRESSION... and.. It works on 4k files!!!

When you connect the SSD card to your Mac/PC before moving files into your machine for editing/CC/etc... just open the clips in MSM select only the part you really need (usually there is a lot of rolling useless part before and sometimes afterwards) and "render" (it's not a render.. no recompression here!) directly in the final folder on your machine! Great!
It takes seconds.. just the time to write the data.. NO RECOMPRESSION (it gets the header from the original file and then just the needed data!)

I sometimes get empty files (seems when the selection is too small).. so just be careful but it's very very useful...

Hope you find it useful as I did

Can you work from copies of the SSD? Any particular structure that needs to be preserved? Not always interested in saving space right off the bat but could be useful at other times.

Sure.. exactly.
As far as I understand it preserves the header and the footer exactly as it is. Worked fine for my BMPC 4K footage.
I didn't do extensive tests with strange formats but every now and then I find it very useful.
Is not compeltely free of bugs. Sometimes it says it did the job but the actual file is only 40k.. so check file size before deleting master.

Sure it can work from SSDs... I use it from SSD to main HD before start if I know I have a lot of junk.. or to extract footage for others to view or work on. If you have a 5 minutes clip with a lot of stuff you don't want you can just extract what you don't want at it will keep in one file only the needed bits. Not bad really