Date: Sat, 12 Sep 1998 10:14:55 -0600 From: Nate Williams <nate@mt.sri.com> To: Luigi Rizzo <luigi@labinfo.iet.unipi.it> Cc: nate@mt.sri.com (Nate Williams), pusateri@juniper.net, freebsd-multimedia@FreeBSD.ORG Subject: Re: NogaTech PCMCIA video cards Message-ID: <199809121614.KAA16816@mt.sri.com> In-Reply-To: <199809121030.MAA20689@labinfo.iet.unipi.it> References: <199809112200.QAA14278@mt.sri.com> <199809121030.MAA20689@labinfo.iet.unipi.it>
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> > FWIW, a PCMCIA camera has *TONS* more bandwidth and *TONS* less > > good to hear that. but just for curiosity, how much more bw ? I guess > the ISA bus tops at some 4Mbyte/s, a 33 MHz, 32-bit PCI bus can do 133 > Mbytes/s during burst transfers, and 320x240x30fps YUV16 video should > be around 5MB/s. Well, given that the MAXIMUM BW from a parallel port device is 115K, there is alot more bandwidth on the PCMCIA bus. > > We used a parallel port camera for awhile, but the performance and load > > on the system became so bad that we were forced to switch to a PCMCIA > > camera, which works much nicer. (Note, this is under Win95, but the > > hardware issues are the same as in FreeBSD.) > > well for the paraller port thing, a poor driver can make a lot of > difference. True, but I'm using the driver supplied by the QuickCam folks. It works pretty well, but in comparison to the PCMCIA card it was night/day. Remember that a parallel port version creates and interrupt/byte (or maybe more), and the PCMCIA does not. The PCMCIA bus might not have enough bandwidth, but if so then there's *NO* way you're going to get enough bandwidth since it's the fastest 'bus' you would have available on the hardware. :( Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message
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