Re: Streaming Audio from Virtual Machine

["David S. Ahern" <daahern@cisco.com>]

On 03/21/2010 01:12 PM, Gus Zernial wrote:
> I'm using Kubuntu 9.10 32-bit on a quad-core Phenom II with 
> Gigabit ethernet. I want to stream audio from MLB.com from a 
> WinXP client thru a Linksys WMB54G wireless music bridge. Note 
> that there are drivers for the WMB54G only for WinXP and Vista.
> 
> If I stream the audio thru a native WinXP box thru the WMB54G,
> all is well and the audio sounds fine. When I try to stream thru a 
> WinXP virtual machine on Kubuntu 9.10, the audio is poor quality
> and subject to gaps and dropping the stream altogether. So far
> I've tried KVM/QEMU and VirtualBox, same result.
> 
> Regards KVM/QEMU, I note AMD-V is activated in the BIOS, and I have a 
> custom 2.6.32.7 kernel, and QEMU 0.11.0. The kvm kvm_amd modules are compiled in and loaded. I've been using bridged networking ..... I think it's set up correctly but I confess I'm no networking expert. My start command for the WinXP virtual machine is:
> 
> sudo /usr/bin/qemu -m 1024 -boot c -netnic,vlan=0,macaddr=00:d0:13:b0:2d:32,model=rtl8139 -net tap,vlan=0,ifname=tap0,script=/etc/qemu-ifup -localtime -soundhw ac97 -smp 4 -fda /dev/fd0 -vga std -usb /home/rbroman/windows.img
> 
> I also tried model=virtio but that didn't help. 
> 
> I suspect this is a virtual machine networking problem but I'm
> not sure. So my questions are:
> 
> -What's the best/fastest networking option and how do I set it up?
> Pointers to step-by-step instructions appreciated.
> 
> -Is it possible I have a problem other than networking? Configuration
> problem with KVM/QEMU? Or could there be a problem with the WMB54G driver when used thru a virtual machine?
> 
> -Is there a better virtual machine solution than KVM/QEMU for what 
> I'm trying to do?

[dsa] I have been able to stream and video in a KVM-hosted winxp VM, and
I have even watched a netflix-based movie. My laptop has a Core-2 duo
cpu, T9550, with 4 GB of RAM. Networking at home is through a wireless-N
router, and I use bridged networking and NAT for VMs.

Host activity definitely has an impact. When streaming I make sure I am
not doing any heavy activity in the host layer, and if I notice jitter
the first thing I do is up the priority of the VM threads using chrt.

David

> 
> Recommendations appreciated - Gus
> 
> 
> 
> 
> 
>       
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