Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
07682 Sound Minor Always Jun 9, 2020, 08:08 Jun 16, 2020, 09:20
Tester Augusto View Status Public Platform MAME (Official Binary)
Assigned To Resolution Open OS Windows 10 (64-bit)
Status [?] Acknowledged Driver
Version 0.221 Fixed in Version Build 64-bit
Fixed in Git Commit Github Pull Request #
Summary 07682: Audio Sync doesn't work if using BGFX
Description Audio Sync is an feature that avoid crackled further in sound. Very good feature.
Possibly MAME was the first emulator to use an feature that sync the sound and video.
Others emulators also has that same feature called with other name being Time Stretching.
Audio Sync was added in MAME in several versions before 2011.
After some versions Audio Sync configuration was removed and enabled internally for good also as was resamplefilter.
Since when BGFX was added in MAME the Audio Sync never worked.

Audio Sync to work need enable refreshspeed.
To test enable OSD slider and refreshspeed.
If Audio Sync is working adjusting refresh rate for a higher value the sound will be slower.

Start any game using D3D output. Rygar and SF2H are good examples.
In OSD select screen refresh rate and adjust for a value above of 60 HZ.
The sound will be slower showing that Audio Sync is working.

Now start any game using BGFX output and adjust screen refresh rate for a value above of 60 HZ.
The sound is not slow meaning that Audio Sync not is working.
Steps To Reproduce
Additional Information
Github Commit
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User avatar
Jun 10, 2020, 20:20
Acknowledging. Have not had time or focus to test.
User avatar
Jun 16, 2020, 09:20
edited on: Jun 16, 2020, 09:21
The links below has good reference about the issue.

# SoundSync
With newer MAME versions there can be problems with stuttering sound if you use vsync or tripplebuffer. Thats because of the emulation gets slowed down and there aren't enough sound samples generated.
SoundSync changes the playback rate of the soundbuffer based on the emulations speed.
If Pac-Man runs with a speed of 98%, the soundbuffer playback gets slowed down to 98% also eliminating the stuttering. However note that the sound also gets a little pitched and slowed down, although most people won't hear this at all. This also works with games that run too fast (NeoGeo for example).

Link about audio sync not working since 0.141