Mame-rr is a fork of MAME with rerecording capabilities, with was started by mz as an experiment and was of pre-alpha quality. It was later picked up by feos and made a bit more usable for general TASing, bumping the version to beta.
There are no plans to improve upon the MAME version which the rerecording fork is based on (0.139), aside from some occasional bug fixes. The longterm plan is to get rerecording added to original MAME instead.
Its movies (.mar) can be submitted to TASVideos. We don't guarantee that it will work well, but it can be used for some decent level TASing.
MESS was not built with rerecording, even though it's theoretically possible.
The source code repository is on Github
WARNING: If you're recording a movie, pause the emulator before calling the Record Movie dialog!
MAME-RR doesn't display input, and the script that's shipped with it isn't too useful, it also doesn't show some nonstandard inputs like Service Mode. Here's a better script: