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Capturing MiniDV tapes Issue
ok, bear with me on this one, and if i miss any information let me know and i’ll try and respond as fast as possible.
so i’m working with a new imac that i boot camped Windows 7 on. I decided to buy an external hard drive to save my project files on and work off of so i don’t have to keep them on the computer itself. I also have a tape deck that i use to capture miniDV tapes that i use with my cameras (Canon GL2’s).
i noticed before i got the imac that it only had one 800 firewire port, so this is how i figured i’d set it up…
imac
out 800 firewire to external hard drive
out external hard drive to tape deck that takes 400 firewireso i thought this would fix my issue of the lack of extra ports on the computer.
but when i use premiere to open a project file that is saved on the external hard drive, and i go to capture some tapes, after i hit stop on recording the video, it takes several minutes for me to get the little window that asks if i would like to save the clip so that it can save it and appear in my project bin in premiere. sometimes it just won’t show up and it freezes up.
i’ve noticed if i rearrange my setup and just have the external hard drive plugged into the computer with a USB, and the tape deck plugged into the computer using firewire, it works fine capturing the footage and saving it to the external hard drive very fast. but now i have an issue that i’m editing footage off an external hard drive via USB. rendering takes a very very long time now. so i have to capture my footage, then unplug everything and rearrange it all, then start back up. and i don’t want to have to do that every time.
is there something i can do that might fix this lagging issue?
i’ve heard that there is something you can buy that is a Firewire hub. it plugs into the computer and comes out and lets you plug up to 2 firewire 800’s into it. do you think a device like this would work?or is there another way to go around this and fix the issue?
again, thank you for reading this and let me know if there is any information that i didn’t supply that can help you make a better judgement
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3 Replies
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I have never had consistently good results from ‘daisy-chaining’ firewire connection to capture video. You might try swapping the devices’ position in the daisy-chain to see if that fixes the problem.
When you capture DV, you are capturing a data stream at the rate of 3.75 megabytes per second. Design-wise, firewire400 transfers data at 50 megabytes per second, so you would think it could easily handle two 3.75mbs streams. (I’m doing this from memory, so don’t quote me on the exact speeds.) Firewire is sort of a bus-protocol in that all the devices see and talk to all other devices.
However, while 50mbs is the maximum data transfer rate, fw is also controlling the drive and the deck. The hard-drive inside the case is nowhere near as fast as the fw connection. The deck may have all sorts of wait-states to accomodate fast-forward/rewind/shuttle/etc. Also, firewire is a very “chatty” protocol and each device spends a lot of time talking to each other device.
When I had a similar problem, I finally added another fw card with multiple ports to my PC. However, you can find fw hubs from B&H (and probably Amazon) for less than $100.
Hopefully some other folks here have had specific experience with fw hubs and Macs.
Jim
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i may need to buy a hub. our tape deck only has one firewire port on it so i wouldn’t be able to switch the arrangement (imac->tape deck->external hard drive).
but now my issue is time i guess. the only place i can purchase a good firewire hub that i’ve found is from B&H and they’re closed till Wednesday for passover :/
i’ve called everywhere around my location (best buy, staples, radio shack, etc…) and no one actually carries these in store. i guess you have to order them online no matter what.
i have read reviews of people saying they use them for their imac’s, but no one has specifically mentioned using them for tape decks. i’m just hoping that i can buy one next week and i don’t have an issue with it.
do you think that using a firewire800 hub coming out of my imac, and having both the external hard drive AND the tape deck plugged into the hub would help my situation? or should that still not work since i’ve now got information going from the tape deck into the hub and then into the computer through one firewire cable, then back out into the hub and into the external drive.
just because daisy chaining them all in the first place made sense in my mind, but apparently that didn’t work. i want to check and see if this will work before i go and buy a $100 device just to find i get the same problems again.
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I have no experience with Macs and firewire hubs. Since you have a suitable work-around, you could wait until you get an answer from someone with experience with Mac/fw before spending money.
I don’t think it is the amount of data, but probably the handshaking between devices on the same port that is causing the problem.
In theory, the hub should resolve any problem.
Then again, “In theory, there is no difference between theory and the real world. In the real world there is always a difference.”
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