EDIT: If you don't feel like wading through this rather large thread, check out my video tutorial - How To Record Arcade Gameplay in MAMEPlus! - for a condensed version of the essential information contained herein. For detailed instructions on avoiding desynch of inp file playback, see here - viewtopic.php?p=2373#p2373
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Here's something really cool for anyone who wants to record best quality gameplay vids in MAMEPlus!.
Up till now I've been using File>Play with Options>Record AVI Output in MAMEPlus! to make my gameplay vids. Doing this creates a massive raw AVI file while playing, which, of course, may cause some lag during play, but doesn't affect the quality of the AVI that gets made. The amount of lag can vary depending on your PC's speed though. Mine was tolerable. I was still able to whip out special moves and stuff so I just put up with it.
Now along comes Elias in PM wanting to make some gameplay vids too. The problem is though, he's getting a huge amount of lag during recording with this method. This gets me thinking. There should be a better way to do this by recording the playback of an input file (.inp), even though there is no specific menu option for this. Here's what I figured out.
Firstly, unlike other GUI MAME's that I've tried before, MAMEPlus! does not come with all the usual folders ready made. MAMEPlus! creates most of them as needed, which is a good thing in one way because you don't have a root directory packed with a lot of folders that may never get used. The downside is it can confuse the hell out of newbies. Anyway, for the purposes of this exercise we need two particular folders in the root directory, inp and snap. Make them if they don't already exist.
Now let's create an input file for a game. I'll use Final Fight as an example. I highlight the game in the Available Arcades list then go File>Play with Options>Record Input. Or another way is to just right click the game in the list and go Record Input. If necessary use the Browse button in the next window (Play window) to locate the inp folder. Either way, once that's done I can see that in the Play window next to Record Input the directory path is set to inp/ffight_000.inp. Now it's time to hit OK and play the game. There is no lag now. I quit out after going through the first stage then check the inp folder and there is a small inp file around 100 KB, ffight_000.inp.
Now let's record the input playback to AVI. I highlight the game again and go File>Play with Options>Playback Input. The inp folder window opens and I choose the ffight_000.inp file that got made before. Now I'm back in the Play window. Here comes the really counter-intuitive part. I can now see a directory path next to Playback Input. That's fine but I need another path next to Record AVI Output at the same time. It's blank though. It's possible to try and type in the correct path but there's an easier way. If I hit the Record AVI Output Browse button here the snap folder window opens up. I simply close that window without doing anything and all of a sudden the correct path, snap/ffight_000.avi, has appeared back in the Play window next to Record AVI Output! Finally I hit OK and MAMEPlus! plays back the input and records to AVI simultaneously. Of course there's some lag on my old P4 while this is happening, but it doesn't matter now because I'm not directly controlling anything in the gameplay.
Once recording of the playback has finished I can quit out of the game and check the snap folder and there is the raw ffight AVI, around 2.8 GB for that stage 1 playthrough. I can now watch it in a media player and bask in the high quality of the recording, or just go straight to a movie making software and edit and downsize the file in preparation for uploading to YouTube.
gl & hf!

Useful Links for Video Processing
VirtualDub - http://sourceforge.net/projects/virtual ... =directory
XviD Codec - https://www.xvid.com/download/