From owner-freebsd-multimedia Sun Feb 4 11:20:34 1996 Return-Path: owner-multimedia Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id LAA25283 for multimedia-outgoing; Sun, 4 Feb 1996 11:20:34 -0800 (PST) Received: from sfi.santafe.edu (sfi.santafe.edu [192.12.12.1]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id LAA25277 for ; Sun, 4 Feb 1996 11:20:32 -0800 (PST) Received: from grasshopper (grasshopper.santafe.edu) by sfi.santafe.edu (4.1/SMI-4.1) id AA28208; Sun, 4 Feb 96 12:16:48 MST Date: Sun, 4 Feb 96 12:16:48 MST Message-Id: <9602041916.AA28208@sfi.santafe.edu> Received: by grasshopper (4.1/SMI-4.1) id AA06248; Sun, 4 Feb 96 12:16:45 MST From: nelson@santafe.edu (Nelson Minar) To: Paul Traina Cc: Sujal Patel , Thomas Davis , multimedia@freebsd.org, linux-connectix@crynwr.com Subject: Re: real-world experience with QuickCam in the kernel In-Reply-To: <199602031007.CAA00405@precipice.shockwave.com> References: <199602031007.CAA00405@precipice.shockwave.com> Sender: owner-multimedia@freebsd.org Precedence: bulk >I found a couple of small bugs in my driver (no big deal), but I'm >now convinced that without some serious head-scratching, doing this >in kernel mode is a big lose. In fact, due to the extra copies and >syscall overhead, I'm at least 5% slower than xfqcam. This will be a problem (how big?) for motion video, but won't matter at all for someone who just wants to make snapshots. I really want to be able to do "ppmtogif < /dev/quickcam > snapshot.pgm". Maybe the solution is to put in a device driver, but have one of the options somehow be to hand over control of the camera to a user process if they want to go to the trouble of hacking the camera themselves. Something would have to be done to insure they don't screw up the camera, though. I looked at an SGI's camera yesterday, by the way, and got seriously bummed. 30fps 640x480 full colour, no noticeable load on the machine. I guess that's what you get when you have real IO. Of course, my Linux box with QuickCam was 3x cheaper :-)