From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com (ext-mx10.extmail.prod.ext.phx2.redhat.com [10.5.110.14]) by int-mx04.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o2UCWtcH028052 for ; Tue, 30 Mar 2010 08:32:56 -0400 Received: from cleopatra.basesoft.com (cleopatra.basesoft.com [82.199.92.137]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o2UCWfYf020980 for ; Tue, 30 Mar 2010 08:32:43 -0400 Received: from localhost (unknown [127.0.0.1]) by cleopatra.basesoft.com (Postfix) with ESMTP id 64E85554CC9 for ; Tue, 30 Mar 2010 12:32:40 +0000 (UTC) Received: from cleopatra.basesoft.com ([127.0.0.1]) by localhost (cleopatra.basesoft.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id qbkHbMDC1KfE for ; Tue, 30 Mar 2010 14:32:37 +0200 (CEST) Received: from [10.0.5.151] (unknown [89.137.114.41]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by cleopatra.basesoft.com (Postfix) with ESMTPSA id 81214554CC7 for ; Tue, 30 Mar 2010 14:32:37 +0200 (CEST) Message-ID: <4BB1EF66.9000500@basesoft.ro> Date: Tue, 30 Mar 2010 15:32:38 +0300 From: Mircea Uifalean MIME-Version: 1.0 To: video4linux-list@redhat.com Subject: [SOLVED] problem with streaming from two webcams with v4l2 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: video4linux-list-bounces@redhat.com Errors-To: video4linux-list-bounces@redhat.com List-ID: Hello. I wrote a couple of days ago about a problem with streaming from two webcams. I had errors when I tried to start both streams simultaneously but individually they both worked fine. According to a page on the matter (not sure if I'm allowed to post links so I'll just quote): "A USB camera uses all the bandwidth a USB1.1 controller can give. Even at low framerates the camera reserves more than half the 11 Mb/s. This means that the 2nd camera gets rejected. Few motherboards have more than one controller. Often 2 or 4 physical connections on a motherboard shares one and the same USB controller. To add more cameras you need to put USB adapter cards. One per camera. There exists cards with full bandwidth per USB socket. These present themselves as for example 4 USB controllers to Linux and they work fine with 4 cameras. Also, many (if not most) cheap PCI USB1/2 cards ($10 range) have a controller capable of supporting 2 x USB1 cameras and an additional USB2 camera per card. With those cards and USB1 extender cards (allowing extension of a USB1 device for up to 100m, typically 50m) you can have a capable surveillance setup using only USB cameras.". So the problem was fixed by adding a PCI card that had some extra USB ports. Hope this helps others that have a similar problem. -- Regards, Mircea Uifalean -- video4linux-list mailing list Unsubscribe mailto:video4linux-list-request@redhat.com?subject=unsubscribe https://www.redhat.com/mailman/listinfo/video4linux-list