From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:47556) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QR3td-0005qn-VH for qemu-devel@nongnu.org; Mon, 30 May 2011 10:56:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QR3td-0006qa-4y for qemu-devel@nongnu.org; Mon, 30 May 2011 10:56:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1026) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QR3tc-0006qV-Q5 for qemu-devel@nongnu.org; Mon, 30 May 2011 10:56:45 -0400 Message-ID: <4DE3B020.2010904@redhat.com> Date: Mon, 30 May 2011 16:56:32 +0200 From: Gerd Hoffmann MIME-Version: 1.0 References: <654825.49014.qm@web65303.mail.ac2.yahoo.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Webcams under KVM and Linux List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Natalia Portillo Cc: Peter Baitz , =?ISO-8859-1?Q?Andreas_F=E4rber?= , QEMU Developers On 05/30/11 14:50, Natalia Portillo wrote: > Exactly what my webcam does is: > > Takes a frame from ANY available V4L2 device (/dev/video0), caches it, > and sends it completely to the guest before requesting any other frame. I think you can double-buffer (i.e. let the host driver fill one buffer while sending the other one to the guest). Probably gives a slightly higher frame rate, but maybe at cost of added latencies. > The guest sees a common USB Video Class Device webcam with no controls > (this can be enhanced easily), so basically you cannot change any parameter. > However all the webcams I tested automatically managed that in the > firmware with no intervention from any of the drivers (host or guest), > changing white balance and brightness to the adequate values. Nice. Patches are waiting for EHCI being merged I guess? cheers, Gerd