long firewire cable

I came across some 25 foot firewire cables at computerplug.com and while it all looks good I have read that the longest you are supposed to go is 15 feet or there will be substantial quality/signal loss.

I haven't had a chance to compare picture quality yet as today Wirecast and my laptop didn't want to play nice, video was not as smooth as it was before in previous tests so I was fighting with that all afternoon while talking to the control room on two phones and typing on the blackberry and working the laptop with my nose as we prepared for a live hit.

I am building a live webcast rapid deployment kit, got a Pelican 1610 case on the weekend and now have to fill it with everything I could possibly need so I have a live-truck in a box, complete with power and everything.

I am curious about any thoughts on the 25 foot firewire cables, I did a quick test and the laptop did recognize the camera but then things got seriously busy.

mark

[DonRotolo]

Remember that in digital communications you have the cliff effect: Either all the data is good enough (and the image is as perfect as it gets) or it's not good enough (and there is nothing).

It might not be as reliable as you want/need. But it might.

[IndySam]

Firewire is funny I have seen things work with 25' and longer cables and I have seen devices have trouble with 5'. It depends on a lot of factors from environmental to who made the chip set in your firewire card.

Originally Posted by Don Rotolo

Remember that in digital communications you have the cliff effect: Either all the data is good enough (and the image is as perfect as it gets) or it's not good enough (and there is nothing).

It might not be as reliable as you want/need. But it might.

Thanks, so I am probably good then since the laptop recognizes the Sony XD HDCAM with that 25 foot cable, just with the small preview monitor I can't really see my picture let alone with all the chaos going on today but yea I guess it's like digital two-way radio (P25 etc), even with almost no signal if you are there you have 100 percent perfect audio, or no audio.

ok, one problem solves, 25 more to go and a kit to build, were's my clone?

[Al Skierkiewicz]

Remember there is more than one flavor of Firewire. It might work at 400 and not even try at 800. Generally low loss cable is thicker/ larger diameter so if this is the same diameter as 1 or 2 meter firewire cables, then I wouldn't trust it. In your applications, a kink or someone stepping on the cable may crash the transfer.

So far so good, now I just have to solve why the video is not 100% perfectly smooth when being captured and rendered on that laptop and I can see it right on my end on the preview that things like moving cars stall just a bit, just not perfectly smooth flowing yet, was ok a couple of times during testing and now it's doing it again, other than that everything it looking quite good.

Originally Posted by Al Skierkiewicz

Remember there is more than one flavor of Firewire. It might work at 400 and not even try at 800. Generally low loss cable is thicker/ larger diameter so if this is the same diameter as 1 or 2 meter firewire cables, then I wouldn't trust it. In your applications, a kink or someone stepping on the cable may crash the transfer.

[Al Skierkiewicz]

Mark,
Don't forget that the XDcam format is MPEG II and is highly compressed already. It is possible that your are losing some data in the transfer so the error correction is resending lost data during those times that you see stutter. What are you using for capture on the laptop? Don't forget that the speed of the disk drive in the laptop can affect performance as well. Do you have the same problems when you are using a shorter firewire cable?

I have used the firewire port on the laptop as well as the express card and also a USB webcam.

When I play back a video off the drive it is 100% perfect, still a tiny bit bit of hesitation live from the camera, I have noticed that keeping the laptop cooler and in a well ventilated environment really helped during testing this morning.

It's looking quite good now....almost.

m

Originally Posted by Al Skierkiewicz

Mark,
Don't forget that the XDcam format is MPEG II and is highly compressed already. It is possible that your are losing some data in the transfer so the error correction is resending lost data during those times that you see stutter. What are you using for capture on the laptop? Don't forget that the speed of the disk drive in the laptop can affect performance as well. Do you have the same problems when you are using a shorter firewire cable?