How to Avoid Desynch of Input Playback in MAMEPlus! (Part 1)
This guide is written mainly with MAMEPlus!
in mind, although the same principles could apply to other MAME builds that offer AVI recording capability. For various reasons, playing back an input file (.inp) to AVI record is the preferred method of making gameplay vids in MAME (refer to my first post
To briefly describe the problem, if the proper preventative measures are not taken then the playback of the inp files of some games with variable outcomes (like versus fighters) can get desynched from what occurred during the original gameplay. For example, as previously discussed, in Marvel Super Heroes Vs. Street Fighter (MSHVSF) it's possible for the input playback to exhibit a different sequence of opponents and stage backgrounds, thereby destroying the viability of the inp file. Fortunately this problem is easily fixed.
The main culprit I've found so far is nvram
, which is an output file that gets created automatically the first time a game is played. If the MSHVSF nvram file is present when an inp file is being recorded for it then the game's input playback will be desynched. Therefore, we need to delete the nvram for MSHVSF before recording any input. To save rummaging around in folders looking for the right file to delete, MAMEPlus! has a convenient way to do this in the GUI.
Simply right click the game in the 'Available Arcades' list and use the 'Remove' option to delete the nvram file.
Now normally if you delete an automatic output file like nvram it will just get recreated the next time the game is launched. Luckily, MAMEPlus! is smart enough to stop nvram being created again if 'Record Input' or 'Playback Input' is being used. Problem solved!
Obviously it is NOT RECOMMENDED
to delete the nvram of CD rewrite games like the parent rom, Street Fighter III 3rd Strike (USA, 990608). I've only done minimal testing of SFIII3S (USA, 990608) so far, but even if it's nvram is already present, using 'Record Input' prompts the game to do the whole 20 minute CD rewrite again anyway. Use the clone rom SFIII3S (Japan, 990512, NO CD) instead to create your movie.
I've heard that MAME's game info screen
can also cause input playback desynch in some games, although I haven't encountered this myself yet and I never will. I always enable 'Skip game info' whenever I configure MAME just because I think that extra screen is annoying. I recommend that everyone else do the same for their MAMEPlus!.
Options>Default Game Options>Misc>tick the 'Skip game info' checkbox>OK
Apparently the cfg
output file can affect some games the same way nvram does, but again, I haven't seen an example of this in testing yet. Like nvram though, cfg is also included in the MAMEPlus! 'Remove' option described earlier if removing nvram alone isn't enough to fix any input playback desynch problems.