Choppy sound in flash applications (YT etc)

[longtalker]

Hi everyone

When my Virtualbox* is running, if I open a Youtube video in a browser outside of the VB, the sound is choppy, and only becomes normal if I turn of the VB. This happens no matter what browser I use, even when the VB is idle, and even after I updated flash in my host OS to the latest version. My PC is reasonably powerful (4GB RAM, Core Duo CPU@2.8GHz) so I'm wondering if I can somehow make VB take up less resources? Right now the VB is using 1600MB RAM and I saw no setting to control CPU priority or something like that. Many thanks for any help!

* v 4.2.12, guest Ubuntu, host Win XP SP3 32-bit

[socratis]

VirtualBox is not using up resources (too much at least). It is your Virtual Machine! You are the one that most probably assigned that much memory and CPU resources. Try lowering them. And if you upgrade to 4.3.x you will see a slider that allows you to cap the CPU. Not sure if it was there in the 4.2.12 version so you'll have to look in your manual.

Please post your log file according to: Minimum information needed for assistance.

[mpack]

The CPU cap has been there for a while, but I wouldn't really recommend using it. Choppy sound means that too much else is going on. Often the user is decoding the video entirely in software (no 2D support) with too large a window size. Capping the CPU will just make it worse.

I believe 2D support doesn't work with Linux guests - I don't play videos in my Linux VMs so I don't know if even 3D support helps at all there.

[socratis]

if I open a Youtube video in a browser outside of the VB, the sound is choppy

@mpack
He's talking about his host. My gut feeling is that he's over-committing resources to the VM and the host is starving.

[mpack]

Right, so he is. VM log file needed.

[longtalker]

Thanks for your replies. Log file now attached.

If I allocated less memory to the VM, the programs I'm running in there would not work properly, so if that's the only solution, then I will unfortunately have to just leave it as it is.

[mpack]

In fact I would increase the amount of VRAM you've allocated - you only have 12MB at the moment, and that surely isn't enough. Doesn't the VM settings dialog give you a warning about this?

The RAM you've allocated looks ok, about the max you can afford without starving the host.

One other thing I notice that your CPU supports VT-x but you currently have it disabled, presumably in your BIOS. You might want to enable that, then give it a try in the VM.

[longtalker]

I've increased VRAM to 100MB out of 128MB max available. I've also enabled virtualisation in the BIOS and vhecked the VT-X option in the VM.

However, the sound coming out of YT in a browser external to the VM is still the same... Anything else I can try? I find it hard to believe that either the VM is taking up so many resources, OR that my machine is not fast enough to handle both an idle VM and a flash video at the same time.

[mpack]

The spec of my PC is almost identical to yours, and I'm not suffering this problem, so I suspect it isn't a simple matter of VM overhead, though of course it's possible that an app running in the VM is causing a high overhead. Perhaps your host audio drivers are not all they could be. My host seems to be using ADI SoundMax audio drivers, the chipset is on the motherboard (no aftermarket sound card).

[longtalker]

This might just be related to audio drivers. The Soundmax didn't work for me (I must have a different card), but I installed another driver that I had for this PC, and now the sound in YT videos is better - not as clear as when VB is off, but definitely less choppy than it was before.

Unfortunately, trying a few other sound drivers didn't make the audio smoothness as it should be, so I guess I'm stuck here. Anyway, still an improvement. Thanks for your help!

[longtalker]

Actually, after a while it comes back to just how choppy it was a before, so no improvement really..

[longtalker]

Not sure if this is relevant, but playing videos from a browser opened *inside* of the VM also results in choppy sound.

The "choppiness" also reflects in a slightly slower passage of time, when looking at the chronometer of the video player, by a factor of about 1.25.

[mpack]

I doubt it's relevant. A VM makes sounds via VBox. Guess what VBox uses?