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[Solved] Audio pops in XP guest

Posted: 26. Nov 2021, 12:27
by Mr.Onion
Hello everyone!

I work as a narrator of audio books, and for part of that work I need to use a piece of software from 2001 that works best in Windows XP.
For a couple of years I've been running XP in VirtualBox on a couple of linux distros (ubuntu studio and mint) without a problem. Lately though, like for the last month or so, I've been getting pops in the recorded audio, and also when playing back audio. When I transfer the files to my host the pops are still there, so it's not only a playback problem. The artifacts sound like xruns, but jackd's xrun counter (on the host) stays at zero.
I've tried reinstalling a fresh install of ubuntu studio (I was using Mint when the problem arose) as well as a fresh install of xp in vb, but the problem remains.

Any idea of what the cause could be? This roadblock keeps me from doing any work at all at the moment and I can't think of anything to try, so I'm very grateful for any input!

Re: Audio pops in XP guest

Posted: 26. Nov 2021, 13:31
by mpack
You need to tell us what version of VirtualBox you're talking about.

Even better, provide a VM log. Make sure the VM is fully shut down, then right click it in the manager UI. Select "Show Log" and save "VBox.log" (no other file) to a zip file. Attach the zip here.

Re: Audio pops in XP guest

Posted: 27. Nov 2021, 19:52
by Mr.Onion
Thanks for replying, and sorry for not getting back until now!
I've attached the log in a zipfile.

Re: Audio pops in XP guest

Posted: 28. Nov 2021, 10:45
by mpack
Audio pops IME are normally caused by high CPU overhead. But, I don't see any obvious reason for high CPU overhead in the VM, except that the Guest Additions have not been installed (I see that you mounted the CD, but you don't appear to have run the installer). Even without 2D/3D acceleration (no longer supported in XP guests), the GAs should I believe still reduce graphics rendering overhead.

Re: Audio pops in XP guest

Posted: 28. Nov 2021, 22:44
by Mr.Onion
That's interesting, because I actually have run the installer, and things like mouse pointer integration and window resizing works just fine... I just did that again, rebooted and have attached the same log. I see some lines (for instance 1237) saying "VMMDev: Guest Additions capability report: (0x0 -> 0x0) seamless: no, hostWindowMapping: no, graphics: no". Does that mean that installation failed for some reason?

Re: Audio pops in XP guest

Posted: 29. Nov 2021, 10:38
by mpack
Mr.Onion wrote:I see some lines (for instance 1237) saying "VMMDev: Guest Additions capability report: (0x0 -> 0x0) seamless: no, hostWindowMapping: no, graphics: no". Does that mean that installation failed for some reason?
No, that's not relevant. That's telling you what GAs API is supported by the host.

If you had installed the GAs, and not just inserted the CD, then there'd be some lines in the log like this:
00:00:05.797804 VMMDev: Guest Log: VBoxGuest: Windows version 10.0, build 19041
00:00:05.802528 VMMDev: Guest Additions information report: Version 6.1.26 r145957 '6.1.26'

Re: Audio pops in XP guest

Posted: 29. Nov 2021, 23:12
by Mr.Onion
Ok, thanks!
I've just made a fresh install of XP and run the Guest Additions installer, and it finished without error messages. I've attached the VBox.log from that machine, and I can't find any lines to mean that GA is installed this time either. Would you mind checking, or pointing me in the direction of a resource where I can learn to interpret this myself? This new machine feels snappier overall and I was able to record without pops for an hour today, so maybe there was something wrong with the old one, but it would be great to know whether the installation of GA really was successful this time in case it acts up again in the future.

Re: Audio pops in XP guest

Posted: 30. Nov 2021, 00:03
by scottgus1
Regrettably, the log comes from a save-stated file, so we can't tell if GAs are installed. Please try the log again after the VM has been fully shut down.

Or look in the XP system try next to the clock in the taskbar. GAs have an income there which shows the installed version when moused over, if GAs are properly installed.

Re: Audio pops in XP guest

Posted: 30. Nov 2021, 10:17
by mpack
I would like to see a screenshot of the GAs installer running, like this:
GAsInstall.jpg
GAsInstall.jpg (78.69 KiB) Viewed 20676 times
Or, a screenshot of the "Programs" list from the XP "Control Panel" after the GAs are installed:
Installed.jpg
Installed.jpg (75.1 KiB) Viewed 20676 times
Basically I want evidence that you're doing more than clicking the "Inserts Guest Additions CD..." item on the VM menu.

Re: Audio pops in XP guest

Posted: 30. Nov 2021, 11:38
by Mr.Onion
mpack wrote: Basically I want evidence that you're doing more than clicking the "Inserts Guest Additions CD..." item on the VM menu.
That's reasonable! I've attached a screenshot from add/remove programs from the new machine.

I've also attached logs from both the old and the new machine (shut down this time). For the old machine I used the XP mode installation guide here (might have been a different guide, there are so many of them), and for the new machine, I used the create new dialog in vb and "inserted" an xp-iso (in case that's relevant).

Re: Audio pops in XP guest

Posted: 30. Nov 2021, 19:34
by mpack
Good. The new log shows the GAs are installed.
00:00:06.338639 VMMDev: Guest Additions information report: Version 6.1.30 r148432 '6.1.30'
VirtualBox is not "XP mode" btw. So the second (ISO) method you used to create your XP VM in VirtualBox is the only method I consider valid.

You have not commented on whether you still get the audio pops with the new VM. If so then you might want to consider using a different audio chipset - I believe Intel HD Audio will work in XP, but I don't have a suitable VM to use for testing here at work. I would also stick to stereo audio, not 5.1 (or better). The less data it has to pipe around the more reliably it should be able to do it. Bear in mind that emulating an audio chipset in real time with no glitches may be no small thing.

Re: Audio pops in XP guest

Posted: 1. Dec 2021, 10:08
by Mr.Onion
mpack wrote: You have not commented on whether you still get the audio pops with the new VM.
It seems to work now, so I'm assuming that it was the failed guest additions installation that was causing the pops.
Thank you for taking the time to help me!

Edit: I would mark this as solved if I could, but it seems it must be done by a moderator now?

Re: Audio pops in XP guest

Posted: 1. Dec 2021, 10:49
by mpack
Mr.Onion wrote: It seems to work now, so I'm assuming that it was the failed guest additions installation that was causing the pops.
Not directly. Installing the GAs makes the VM run smoother, which reduces latency and makes audio pops less likely.

Another thing that would help (a lot) is having two CPU cores assigned to the VM. Unfortunately it's quite difficult to change this after XP is installed: if it installed the single processor HAL (*) then it will simply ignore any extra cores you give it later.

(*) To tell if the single processor XP HAL is installed, go into XP's Device Manager and expand the "Computer" branch. If it says "Advanced Configuration and Power Interface (ACPI) PC" then it's the single processor HAL and will ignore additional cores. If it says "ACPI Multiprocessor PC" then the multprocessor HAL is installed. Instructions for replacing the XP HAL post install are here: viewtopic.php?f=7&p=111649.

Re: Audio pops in XP guest

Posted: 1. Dec 2021, 12:29
by Mr.Onion
mpack wrote:
Mr.Onion wrote: Another thing that would help (a lot) is having two CPU cores assigned to the VM.
Thanks for the tip, I've been wondering whether that could make a difference! Since it's quite trivial to just make a new machine and migrate my work there, I might just do that when I get the time!