Glitchy Audio

[WDeranged]

I recently updated to the latest stable build (windows) and I've been getting lots of audio stutters and glitches. It's especially bad when selecting dialogue but games that have streaming background music (COMI) are also pretty bad.

I installed the most recent daily build and it's much improved, though still not perfect. Another strange issue is the clock tower bell sound in COMI is glitchy.

[Alien Grey]

I'm wondering what kind of device you''re uisng to run ScummVM?

There's three devices that I'm uisng to run ScummVM and one of them does also has lots of sound glitches when running ScummVM. The one that does run ScummVM with sound glitches is a GPD Win with an Intel Atom® x7-Z8750 Processor. That probably means that every device that uses an Intel Atom® Processor is going to be having these sound glitches.

I've tried all kinds of different settings with ScummVM but couldn't get rid of these sound glitches.

Before anyone wants to say that it's because an Intel Atom® Processor is too slow. I don't have any sound glitches with any other game or application I'm using on that device.

[Alien Grey]

I did some more testing on my device that gives me audio glitches and for me it only happens with MT-32 emulation or FluidSynth with large soundfonts. Everything else seems to sound just fine with latest stable build. I haven't used this device for a long time but I needed to replace the old battery so I'm going to spend some more time with ScummVM and also try some older releases because I think I did get MT-32 emulation running much better in the past.

[Alien Grey]

Tested with ScummVM 1.9.02 and MT-32 emulation is crystal clear like I thought it was. Looks like there is an issue with the sound and the new stable build.

[criezy]

In ScummVM 2.0.0 we updated the MT-32 emulation code to use Munt 2.0.3. This version of Munt switched to a more precise, but more CPU-intensive sound generation. It could explain some sound glitch issues with ScummVM 2.0.0 and above on low end devices.

[ZvikaZ]

In ScummVM 2.0.0 we updated the MT-32 emulation code to use Munt 2.0.3. This version of Munt switched to a more precise, but more CPU-intensive sound generation. It could explain some sound glitch issues with ScummVM 2.0.0 and above on low end devices.

Do you think that he can use a recent ScummVM, with external munt (instead of using the built-in), and install an old enough munt version?
Should it solve his problem?

[criezy]

Do you think that he can use a recent ScummVM, with external munt (instead of using the built-in), and install an old enough munt version?
Should it solve his problem?

Yes. That would be my suggestion for those experiencing the issue if they are on a platform for which external munt is available.
The issue was previously reported for PPC macs, and as far as I know there is no external munts for those. But for Windows computers that should not be an issue.

[Alien Grey]

I'm currently using ScummVM 2.0.0 and MT-32 emulation is still fine. I also checked CPU usage and it's only 13%.

With ScummVM 2.1.2 the MT-32 emulation starts to be glitchy and it's worse with ScummVM 2.2.0.

[Alien Grey]

Do you think that he can use a recent ScummVM, with external munt (instead of using the built-in), and install an old enough munt version?
Should it solve his problem?

Yes. That would be my suggestion for those experiencing the issue if they are on a platform for which external munt is available.
The issue was previously reported for PPC macs, and as far as I know there is no external munts for those. But for Windows computers that should not be an issue.

Is there a tutorial somewhere that explains how to do this for ScummVM and Windows?

If I can get this to work I can test different munt builds.

[Alien Grey]

Never mind. I figured it out. I'm using Munt 2.3.0 and that fixes the sound issue.

[ZvikaZ]

Never mind. I figured it out. I'm using Munt 2.3.0 and that fixes the sound issue.

I'm glad that it solved your problem.
Interestingly, I thought that your problem will be solved by going to *older* munt version, not *newer*.

@criezy, maybe we should update the built-in version to 2.3.0 as well?
It's possible that they fixed some bug that was introduced at our current 2.0.3 version.

[criezy]

@criezy, maybe we should update the built-in version to 2.3.0 as well?
It's possible that they fixed some bug that was introduced at our current 2.0.3 version.

The version we are using in ScummVM 2.2.0 is Munt 2.4.0 (ScummVM 2.1.x uses Munt 2.3.0, and ScummVM 2.0.x uses Munt 2.0.3).

Using an external munt can also help to spread the load on a separate CPU. So it might be what makes the difference here. But there could also be a different issue with the built in munt, such as audio buffer too small (in which case changing it in the config file could help).

[Alien Grey]

Munte 2.4.1 was released yesterday. No binary. Only the source code so can't test it.

[Alien Grey]

Tried it with a single core and no issues. CPU load is around 12%.

[WDeranged]

I'm running on Windows 7 x64 with a relatively heavy spec. Curse of Monkey Island doesn't use MT32. Is the MT32 emulation always active in the background?