09229: moomesa: volume cuts sometimes after sound effect triggers

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
09229	Sound	Minor	Always	7 days ago	5 days ago

Tester	hap	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows 11/10 (64-bit)
Status [?]	Acknowledged			Driver	konami/moo.cpp
Version	0.278	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	09229: moomesa: volume cuts sometimes after sound effect triggers
Description	It has volume cuts sometimes after sound effect triggers, such as the player shot sound. mame moomesa -wavwrite 1.wav is fine, so it seems like a bug in sound.cpp? If I disable audio effects (or switch resampler type), the bug is still there. If I skip the sound_stream_update in k054539.cpp, the bug is still there. It continuously writes to active_w in k054321_device, which calls propagate_volume(), which calls m_speaker->set_input_gain, which calls sound.cpp sound_stream::update(), I think the bug is in there. I assume it can be worked around it like this: if (m_active != data) { m_active = data; propagate_volume(); } But that doesn't fix the underlying issue in sound.cpp moomesa isn't the only game using this chip. You can hear the volume chopping too in for example xexex after you go to service mode, and modify the global volume.
Steps To Reproduce	Just play the game, and shoot a lot.
Additional Information
Github Commit

Flags
Regression Version	0.278
Affected Sets / Systems	moomesa

Attached Files	obs studio recording.mp3 (180,330 bytes) 7 days ago Uploaded by hap

No.23547 Robbbert Moderator 7 days ago	Can't get the sound to misbehave. But it seems you've already fixed it?
No.23548 hap Developer 7 days ago	No I did not fix it.
No.23550 hap Developer 6 days ago	I worked around it here for this specific use case: https://github.com/mamedev/mame/commit/e298ea572791f4abb85cd9805124b79d6e5f7beb I say workaround, but the commit itself is not bad in any way. It makes sense to skip an unnecessary call to update() if the gain value did not change. The issue can still be reproduced in moomesa service mode: Go to game options, put the cursor on sound volume, and the music is choppy. The bug in sound.cpp: I suspect it may be doing commit() twice. This: m_write_position += samples;