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ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
01815 Save/Restore Minor Always May 19, 2008, 21:23 May 22, 2008, 05:15
Tester Tafoid View Status Public Platform MAME (Self-compiled)
Assigned To aaron Resolution Fixed OS Windows 2000
Status [?] Resolved Driver
Version 0.125u1 Fixed in Version 0.125u2 Build Athlon
Fixed in Git Commit Github Pull Request #
Summary 01815: All Sets: Saved machine states do not properly adjust to changes in -samplerate
Description Simply, if you decide to run a game at a sample rate that is different than that which the STATE was made, the pitch of the audio is offset based on the difference in HZ between the original STATE sample rate and the newly issued sample rate.

I've tested drivers which are set up for Save States (-autosave) as well as sets that are not set up for States (Using LeftShift + F7) - they've all reacted similarly.
All tests were without any video or audio syncing.
Steps To Reproduce For this example, we'll use the set PACMAN

- Make sure your MAME.INI is default in samplerate (48000). Delete STA\PACMAN\auto.sta if that is present (or move aside if you are saving scores).
- TYPE: mame -autosave pacman
- Let the emulation start and boot up, you can exit MAME anytime.
- NOW TYPE: mame -autosave pacman -sr 36000

Observe the audio output - the pitch is much lower than expected!

This also holds true for a STATE which is created at a lower sample rate, except, the pitch is increased in this case. Simply reverse the MAME commands above (36000 first.. then default 48000 after). This also causes an audio artifact that shows itself in rapid duplication of audio bits.. with obvious stuttering.
Additional Information I had a discussion about this on MAME Testers forum nearly a year and a half ago. I tried to reference the forum posts but they've already been moved off.
At the time, I was told that this was not really a bug. I still insist that it is indeed a bug and which even has a version in which the regression first occurs.
Github Commit
Flags
Regression Version 0.103u4
Affected Sets / Systems All Sets
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No.01012
Haze
Senior Tester
May 20, 2008, 11:06
Well it's clearly a bug, whether it's a bug by design or not is rather irrelevant.