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Capturing HQ to an external drive

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  • #16
    Originally posted by Bluetongue View Post
    Canopus HQ is still compressed and the bit rate to the hard drive is around 20mb/s. an IDE 7200rpm drive can handle 25mb/s so you have a small overhead available, as quoted USB 2 transfer is around 400mb/s so an IDE drive in an enclosure is well within the capability of the USB transfer rate.
    Your units are a bit off here...

    Canopus HQ averages around 120-160 Mbit/sec, which equates to 15-20 MByte/sec.

    USB 2 is 480 Mbit/sec max, which equates to 60 MByte/sec max.

    Your conclusion is still correct though - a single IDE drive won't exceed USB 2 maximum transfer, assuming nearly-full USB 2 bandwidth is available.
    It's a different story if you have multiple drives connected to the same bus as they will all have to share bandwidth, but the same is also true for FireWire and SCSI.

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    • #17
      Originally posted by GrassValley_BH View Post
      Canopus HQ averages 120-160 Mbps, so if you're not doing other things over USB and your USB drive isn't fragmented or using a stupid (underperforming) USB bridge, then it should be OK.
      When I capture to the HQ format (standard quality) my file sizes end up about three times that of HDV, which suggests an average bit rate of 3x25 = 75 Mbps or about 10 MB/sec. What indication do you have that it's as high as 120-160 Mbps?
      Edius 6.5 on Lenovo W520 laptop: Intel Core i7-2720QM @2.2 GHz, Nvidia graphics card, 8GB RAM, Windows 7 Pro 64-bit. Canon Vixia HF-G10, three Sony HDV video cameras and one Canon 7D.

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      • #18
        Originally posted by kwshaw1 View Post
        What indication do you have that it's as high as 120-160 Mbps?
        Because I have a 203 MB clip that's 13 seconds long... which comes out to being about 123 Mbps, and this clip is pre-alpha support. :)

        That said, it's both resolution, framerate and content-dependent. Since it's a variable bitrate, it'll go up and down.

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        • #19
          Firewire 800 and bandwidth

          Originally posted by GrassValley_BH View Post
          Your units are a bit off here...

          It's a different story if you have multiple drives connected to the same bus as they will all have to share bandwidth, but the same is also true for FireWire and SCSI.
          I have three LaCie external drives hooked to one PCI slot interface card on a Dell workstation. I soemtimes get "Drive nor fast enough" when capturing HQ. Is there a better configuration for these drives? When I'm capturing, should i turn a couple of them off?

          The problem onoy occurs during capture.

          Jacques

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          • #20
            Originally posted by Jacques Ménard View Post
            I have three LaCie external drives hooked to one PCI slot interface card on a Dell workstation. I soemtimes get "Drive nor fast enough" when capturing HQ. Is there a better configuration for these drives? When I'm capturing, should i turn a couple of them off?

            The problem onoy occurs during capture.

            Jacques
            What kind of bus are the drives on? FireWire is a repeater technology. USB is hub-ed.

            Does it perform better with fewer drives connected?

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            • #21
              Has anybody tried the new WD mybook world editin with Gbit ethernet? Theretically, correct me if i am mistaken, 1000Mbit/8 = 125MB/sec. Any experience?

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