Posted: 8/8/2019 12:13 PM
Post subject: Playing Back Input Files in Stella
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Lobsterzelda
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Skilled player (1259)
Joined: 3/17/2019
Posts: 284
Hi everybody. I have been experimenting with the Stella emulator to see if I could get it to play back Atari 2600 TASes on it. I have been able to create a program that has Stella run the inputs from a TAS made in BizHawk. However, there is one issue with this. When I run the same movie back, the results I get are different each time. For example, in the game Pitfall!, the TAS hits the log on the first screen (as a result of the TAS being made in BizHawk and not synced to Stella). How many points you lose depends on how long you are touching the log for. However, every time I reset Stella and run the input file back, I lose a different number of points from the log: sometimes I lose 8, sometimes I lose 12, sometimes I lose 9 etc. Does anybody know why this might be happening? I assume it's due to differences in memory initialization, so if somebody knows how BizHawk initializes Atari 2600 games' memory, it would help me figure out a way to get Stella to consistently play back an input file. Thanks for any help that y'all can provide!
Posted: 8/8/2019 12:35 PM
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InfamousKnight
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Joined: 9/12/2014
Posts: 543
Location: Waterford, MI
Stella works in libtas. Have you tried that?
Posted: 8/8/2019 12:54 PM
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MESHUGGAH
Other
Skilled player (1919)
Joined: 11/14/2009
Posts: 1353
Location: 𝔐𝔞𝔤𝑦𝔞𝔯
NES TASer of 2013 NES TAS of 2013 NES TAS of 2012 NES TAS of 2011
I'm not familiar with Stella other than there were a proof of concept TAS of Dragster with the same in game time as the first published TAS. So you get desync at different points, that is something is changing each time you are trying to replay the movie. According to https://stella-emu.github.io/docs/index.html#CommandLine you should try to disable everything that makes random modifications like -<plr>ramrandom <1>. If BizHawk uses a different pattern, you will probably need to manually change the whole region right before the first line of code would be executed in Stella debugger.
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