Re: [Qemu-devel] Re: Webcam solution for QEMU

[David Ahern <dsahern@gmail.com>]

On 05/09/2010 08:28 PM, Natalia Portillo wrote:
> Hello Arnon,
> Hola Albert,
> 
> Wouldn't be easier to implement a custom video capture device?
> You can always emulate a simple one, like (to say) OV511 webcam, and feed that emulated device with video taken from any V4L2/DirectShow/BDA supported device (real host webcam).
> 
> I think this way, timing issues will not arise, and will support indeed any webcam or video capture device (tuners) past, present, and future.
> 
> Of course not to say video will come with a little lag to the guest but that lag will be a lot less than the timing lag connecting host<->guest devices in a more directly way.
> 
> That's just my 2 euro cent.


Earlier this year I got a streaming audio device to work as a
passthrough device. The biggest pain was needing to modify the guest
driver to increase its number of outstanding URBs. That was required due
to the way isochronous requests are handled within the USB controller.

Based on that experience I thought an emulated device in qemu would help
with the low level timing issues. In addition it would provide an option
for VDI wherein the VM on a remote server is running a video/audio
streaming ap that requires webcam interaction (e.g., video phone or
integrated conferencing software).

Are you planning to create such a device for qemu?

David