Will an external FW drive help with DV capture? |
January, 07, 2003 10:52 PM |
chrisdold |
I have a PowerComputing PowerCenter Tower with a G3 333Mhz and a PCI USB/Firewire card that can only capture about 10 seconds of Digital Video from my camcorder before it gets REAL choppy. I'm assuming this is because the standard SCSI interface is too slow. I have 7200 RPM drives, but have checked the speed of the drives and I get a max of 4.4Mbps throughput to any device on the SCSI chain. This makes sense, since standard SCSI runs at 5Mbps, I belive. I am wondering if adding an external FireWire drive will help by bypassing the SCSI chain entirely. I am still worried about limitations in the PCI bus or processor speed. Does anyone have experience with this on an OldWorld machine? Also, does anyone know what the data transfer rate of DV is for capture? Thanks for any help! |
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E: Will an external FW drive help with DV capture? |
January, 08, 2003 3:39 PM |
chrisdold |
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I have seen FW/USB2 cards that claim they are Mac compatible, but they always have a little caveat that they are only supported at USB1.1 speeds (12Mbps). I really thought that it was Apple that needed to implement support for USB2 in OSX before companies would be able to write the device drivers for their cards. The theory was that Apple would not do that until they had an interface faster than the 480Mbps of USB2, which they now have with FW800. It only makes sense to put the USB2 drivers in the OS now to support the current interface standard. If anyone has USB2 support working at better than 1.1 speeds I would love to hear about it. I think I'll start a new thread for it since it does not have much to do with the original DV question. Thanks again for the input! |
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E: Will an external FW drive help with DV capture? |
January, 08, 2003 2:30 PM |
joevt |
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The Sonnet Tempo Trio has FireWire, USB2 and ATA. I don't have any USB2 devices but I plan on getting a fast portable FireWire/USB2 drive. It would be interesting to test transfers from DV to FireWire, USB2, and ATA using that card. The speeds of the three interfaces connected to a drive are ordered (fastest to slowest) ATA, FireWire and USB2 but since DV uses FireWire also, it might be better to use a drive connected to either ATA or USB2. If DV is only 5 MB/s then that leaves 35 MB/s of bandwidth for a FireWire drive which might make it ok also. On my 8600, the speed of the internal SCSI bus is 10 MB/s (external is 5 MB/s). That might be fast enough if my hard drive can sustain faster than 5 MB/s speeds. |
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E: Will an external FW drive help with DV capture? |
January, 08, 2003 12:21 PM |
marcush |
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Supposedly, OSX already has USB 2 support. I don't have any USB 2 devices to test it with though. Smartdisk has USB 2 drivers for their FW/USB2.0 card which I downloaded but never installed. I don't have any real recommendations for cards except Ratoc. It performs perfectly on both FW and USB. The smartdisk card looks good because it has more FW and USB ports than other cards I've seen. The price is good too. $80, I think it was. |
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E: Will an external FW drive help with DV capture? |
January, 08, 2003 4:17 AM |
john.england |
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I second that idea about a SCSI card. I use an Adaptec 29160n in my Power Mac 7600 and get transfer rates of 38 megs a second with Fujitsu 15k hard drives. Your answer to get around the internal scsi is to go with a scsi card. I've seen some ATTO ones going pretty cheap on ebay too! |
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RE: Will an external FW drive help with DV capture |
January, 08, 2003 1:51 AM |
chrisdold |
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Thanks for the info. I'm assuming that your USB2 card only works at USB1 speeds? I was hoping that MacWorld would bring USB2 support to the Mac, but no such luck. I'm going to start looking for a card that will work with USB1 right now and hopefully migrate to USB2 when Apple releases drivers. Any recommendations? |
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E: Will an external FW drive help with DV capture? |
January, 08, 2003 12:13 AM |
marcush |
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The transfer rate required for DV transfer is 5MB/s. You could resolve your problem with a firewire card and firewire drive but if you want to save some money a Ultra SCSI card with a transfer rate of 20MB/s would suffice. I use a Ratoc Firewire/USB2.0 card to capture to an internal 120GB IDE drive. |