From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx3.redhat.com (mx3.redhat.com [172.16.48.32]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id m89J8IfZ031291 for ; Tue, 9 Sep 2008 15:08:19 -0400 Received: from mail.gmx.net (mail.gmx.net [213.165.64.20]) by mx3.redhat.com (8.13.8/8.13.8) with SMTP id m89J7g3e020287 for ; Tue, 9 Sep 2008 15:07:43 -0400 Date: Tue, 9 Sep 2008 21:07:27 +0200 From: Daniel =?iso-8859-1?Q?Gl=F6ckner?= To: Ming Liu Message-ID: <20080909190727.GA2184@daniel.bse> References: <20080908160012.574456184D5@hormel.redhat.com> <48C5948D.5030504@migmasys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48C5948D.5030504@migmasys.com> Cc: video4linux-list@redhat.com Subject: Re: a multichannel capture problem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: video4linux-list-bounces@redhat.com Errors-To: video4linux-list-bounces@redhat.com List-ID: On Mon, Sep 08, 2008 at 05:09:33PM -0400, Ming Liu wrote: > 1. Is there any example codes that I can follow to estimate the frame > rates using switch channel approach? Motion (http://www.lavrsen.dk/twiki/bin/view/Motion/WebHome ) is said to support multiple inputs of one card "at the same time". I never tried it, though. > Can I do this by using standard V4L2 APIs, or I will need to deal with > the driver? You can do this with V4L2. Some time ago I made some experiments changing the input at random times using direct hardware access while capturing. IIRC the chip will skip at least one complete frame before it continues to capture. > 2. If I choose a multi-chip PCI based video capture card, is there any > limit from the bandwidth? Of course. A few days ago we had a discussion about bandwidth issues when using 5+ bt8xx cards to capture 640x480 in YUV 4:2:0. When there are other chips using the PCI bus (f.ex. the harddisk controller), the limit will be lower. > Are there any sample codes available? Motion can handle multiple devices at the same time as well. > 3. In the program point of view, is there difference between using > multi-chip card and several single chip cards? No. Daniel -- video4linux-list mailing list Unsubscribe mailto:video4linux-list-request@redhat.com?subject=unsubscribe https://www.redhat.com/mailman/listinfo/video4linux-list