I've done 3 hr. live captures to external USB drives with no problems and no dropped frames.

Mike

Firewire will work. It's a one way stream.....USB both directions, that's what slows it down.
Check out my questions about eSATA in the post about Docking stations for $25.
eSATA will transfer at 3Gbps, while Firewire is 400Mbps and USB2 is 480 Mbps (2 way stream)
http://www.sonycreativesoftware.com/forums/ShowMessage.asp?MessageID=588356&Replies=9

Not sure what you mean by oneway stream. .

But USB will work. I just would be more comfortable with firewire.

The Docking station you linked to in the other thread will only use USB speeds with a SATA drive, although someone else linked to a docking station that does have a SATA connector to computer as well.

Quick easy explanation.

http://www.firewire-1394.com/firewire-vs-usb.htm

Dave T2

I capture to an external USB 2 drive a couple of times a week now going for 9 months. I use Adobe OnLocation as the capturing software [it does a lot more than just the capture] and it's FireWire from camera to laptop, and USB to the portable HD [just an 80GB portable Maxtor, 5400RPM]. Not a single dropped frame in over a hundred hours of capture. I do have to make sure that the drive is either empty or defragged or I get a "drive too slow" message from OnLocation. But even when that happened, no frames were dropped.

One way stream was probably a wrong discription, but that was the way it was explained to me at one time. That USB has two way streaming (back & forth) and Firewire streams one way. All I know is my Firewire has never been interrupted and I've heard that not having the back & forth info exchange is what makes it faster / more reliable than USB

It was my other link that would let me connect my internal SATA connectors to a "Slot cover adapter" that would give 2 eSATA connectors on the back of my PC. Allowing me to connect 2 more drives via external eSATA connection for $7.95.
My idea is to Firewire to computer but go directly to external via eSATA.
I know of no cameras that output via eSATA .... yet. But at the great transfer rate it has, it seems like they should have adapted it, at least for HDV.

I have captured to over a dozen external USB drives, both DV and HDV, and never had a problem. By contrast, I have sometimes had problems with Firewire drives, but only because some of my older computers don't seem to like both a camera and Firewire drive turned on at the same time, even if they are not using the same port. However, others don't seem to have this problem, so I have assumed it is a local problem to my old computers.

USB will work fine for DV, HDV, and probably anything else in that lower bitrate range.

I too capture regularly to USB drives - including the small WD bus powered drives. Never had a problem using either Sony's VidCap or, more recently, Adobe OnLocation. I rarely put tape in my camera when I'm shooting fixed.....

Rick

Hi,

We capture directly to USB drives and bus powered USB drives every day, sometimes for hours (depositions). We use Scenalyzer most of the time but have used the capture programs in Vegas and PPro.

Mike

"One way stream was probably a wrong discription, but that was the way it was explained to me at one time. That USB has two way streaming (back & forth) and Firewire streams one way. All I know is my Firewire has never been interrupted and I've heard that not having the back & forth info exchange is what makes it faster / more reliable than USB"

Firewire uses DMA (Direct Memory Access). One device tells the other device "I have data to send" and the processor is only involved long enough to tell the sending device where to send the data and the receiving device to interrupt me when you get all the data. The devices then complete the data exchange without the involvement of the processor. USB uses a protocol very similar to the serial port (I wonder if that's why it's called the Universal *Serial* Bus). The sending device interrupts the processor to say "I have a byte for you" The processor takes the byte and puts it into memory then waits until the sending device interrupts the processor with another byte. It does this for every byte. In the case of a device to device transfer, the processor acts as the traffic cop taking bytes of data from the sender, buffering them in RAM and sending the bytes to to the receiver, using a similar "interrupt me when you are ready for the next byte".

On the surface, it seems complex and you would think that USB should slow the processor to a crawl, but it doesn't. In the time it takes for a device to interrupt the processor between bytes, the processor may execute thousands or millions of instructions.

While the design throughput for USB, USB2, Ultra USB, Firewire and Firewire800 seems fast, no transfer can go faster that the slowest component in the data stream.

I found a web site that explains this better: http://www.pcguide.com/ref/hdd/perf/extSpeed-c.html

Here is a portion of that discussion:

"Once you get above the internal transfer rate (burst rate), the extra "room" is only of value if whatever you are trying to read from the disk is already in the buffer. If the hard disk itself can only do sustained reads of 7 MB/s, then over time, the extra 9.6 MB/s of the 16.6 MB/s interface speed does not do a lot for you. However, having that extra slack is of use in making sure peak transfers have the capacity they need. Many hard disk manufacturers try to trick their buyers by putting the 16.6 MB/s speed of the interface in big letters in their ads, but as you know now, this is not the most important number. The newest drives support Ultra ATA and its 33.3 Mb/s interface speed, which makes the confusion even worse because virtually no systems are going to exploit even half of that capacity right now."

In conclusion, USB2 is fast enough for DV or HDV video capture.

"The newest drives support Ultra ATA and its 33.3 Mb/s interface speed"

That article has to be over ten years old. Current hard drives are capable of transfer rates of over 100 megabytes/sec, so having an IDE-6 or SATA150 interface at a minumum is mandatory.

HDV and DV require no more that 4 megabytes/sec to transfer in real-time so, yes, USB2 is plenty fast enough.