*Note before reading* This won't help corrupted TAS's made for publication, sorry :( ... It's mostly for things like showcasing a point, or a playthrough/walkthrough, etc on YouTube.. I myself use PSXJin for playthroughs so I don't have to have a sloppy movie (like videos that constantly reload save states to do something, it looks so sloppy and I hate it xD), mainly because I use save states to come back to where I was after I leave :p. Anyway...
This problems exist with both Svn0 and Svn715 of v2.0.2 of PSXJin
I came across this problem in PSXJin a few hours ago, and had actually found it catastrophic, though about 20 minutes ago found a solution (so that's good). Anyway, this won't affect most movies because as far as I know, it only affects extremely long (5+ hour) movies... Like FF7 and FF8.
If recording a movie of this length, if you accidentally (or possibly intentionally if you're not sure of what you're doing) click File -> Recent -> any thing in this list (basically you're last few played games), it will, as what it looks like, overwrite the movie file leaving you with a movie that is 1 frame in length (note: this also does the same for any movie file), though unlike a movie that is 5 minutes in length, and a movie that is 8 hours in length (my tid bit), the movie that is 5 minutes in length can have a save state reload it's data, and since 5 minutes isn't that long, it will probably instantly restore it. However, in the sense that your movie is 8 hours in length, if you do the whole recent games thing, and try to reload a movie, it will, bluntly stated, freeze the emulator because it's overloaded with all of your input.
If you try to click the X button to close the emulator, you'll get the whole "this program isn't responding", and if you try to close the process/tree by the task manager, it won't close. So, say that you let it do this, say you're at frame 1,567,432 (just a random number), it will take about 5-12 minutes to load it, and when it does you will no longer be recording the movie (I guess it crashes the movie recording?), and you'll just be in the regular game outside of the movie, you will also have no sound, period... I suggest here you save the game (via save state, and via the in game saves, also make sure you're saving to an actual memory card, not a temp one :p). Then make a new movie, using the same game (obviously), and be sure to have it from "Start from power on + current memory cards".. Then config -> memory cards, and make sure you're using mcd001.mcr in the first slot. Reload the save via the in game loader, and problem solved.
I guess the whole reason I'm bringing it up is if the devs of Jin could possible add a safe fix for this? It'd be a shame if it was a TAS doing this, all that hard work for nothing and all :'(.