Alright, after (effectively) disabling the latch filter on my device, I was able to verify this using your poll-based dump.
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I wanted to know what the difference was. First of all, the polling sequence done by the game is fairly typical. No non-standard polling, or weird clocks, etc. Each frame consists of: Latch, clock*8 player 1, clock*8 player 2, Latch again, clock*8 player 1, clock*8 player 2. Though the time when the polls appear within a frame changed wildly.
So I compared your poll-based dump, and my frame-based dump, by incrementing through each set of inputs on a frame by frame basis. Thus your dump should theoretically have two identical sets per frame, which should match the frame-based dump. Based on the
analysis here, I found the first difference.
I traced this moment back to roughly movie frame #2719. Which is the point where the player performs the first glitch of the run. Using onmemoryread/onmemorywrite in a lua script for memory address 0x4016, I found that on most frames, just as seen on hardware, 2 latches occur as described earlier. But on frames #2715 and #2716 of the emulator, only 1 latch occurs on each. I located where this was happening on hardware, and
it turns out that VSYNC occurs after the 1st latch's polling sequence, causing a short delay (~0.5ms) until the 2nd latch occurs, and is why only 1 latch appears on these frames on emu. Trying to change the latch filter to account for this, didn't work, and seemed to consistently change which frames get this collision..
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If we think about frames as being wholly separate from each other, then theoretically the frame-based dump should have still worked. The reason it didn't in practice, is because the latch-filter is much too large for this odd case (which happens multiple times throughout the run), and a single value may not be sufficient. To me, this throws into question why some of us even bother using a latch filter at all. Perhaps in the past, it was necessary because emulators weren't accurate enough? Also makes me wonder if using a poll-based dump would allow me to verify TASes that have failed for me in the past.
