Bumping because this really needs more views. Using the tool makes DS TASing way less painful in every way, especially touchscreen TASing. Many DS tasers still don't know about it (I showed it to Really_Tall just today.)
Also, the source is available at
https://github.com/SuuperW/DeSmuME-Movie-Editor
Here's what it looks like:
The tool is somewhat similar to TAStudio. It allows non-linear editing, and branches.
Most of all, it doens't restrict traditional TASing: you can use it alongside, using its features when needed.
You can jump to and edit any frame of the movie, and it reloads instantly. (No more Read+Write to edit a mistake 3 frames prior!)
You can edit stylus coordinates with granular precision and modify them from their old states. (No more manual stylus TASing or AutoHotKey scripts!)
You can do bulk editing and even insert new frames in bulk.
The movie editor also features something similar to branches, called parts. You can take any segment of the currently edited movie and keep it in memory. This creates a partial input. This can be then saved to disk, reloaded later on, and even inserted into the movie at a different frame point.
Parts allow for a workflow similar to TASeditor branches, starting many parts from a starting frame to compare different strategies, for instance.
But they also allow easy splicing. There is no limit on a part length: it can be used to capture entire long segments of a movie. This means you can do certain segments independently of each other and splice them all together at the end, or while developping a TAS to copy-paste common parts.
The movie editor warns for most desyncs, however you should keep an eye out for them.