Help me understand video capture

I have a FireWire port on my computer that I use to capture digital video from my DV digital video camera. No sweat. I use Pinnacle Studio DV, which shipped with the FireWire card. It captures the signal as an AVI file.

I have lots of older analog camcorder tapes that I would like to manipulate digitally and would prefer to avoid having to use the digital camcorder to record them from the analog camcorder. Although I could do that with no additional equipment, I am concerned about the signal loss. Then again, maybe I would get equivalent signal loss going from the analog camcorder to a computer anyway. (I think the signal loss from the digital camcorder to the computer is negligible; at least, I don’t get dropped frames.)

So here are the questions:

Would I experience noticable signal degradation if I copied an analog tape to a digital tape using two video cameras?

What hardware/software would I need to use my computer to directly capture an NTSC signal input as an AVI (or other digital video) file?

Which of the above two options is best?

  1. No more than if you used other software to compress the video to AVI. As long as the avi files produced by your camcorder are acceptable, there will be no need to recompress which would cause degredation.

  2. I think windows movie maker has the capability to capture video, but not to compress it to avi. There are about a million programs for this, someone else can make a recommendation.

I’m sorry I think I misread the OP, I was thinking that the camcorder stored avi files on tape and they were transferred as is to the computer. If this is not the case, then there likely would be degredation.

My digital video camera uses some format unknown to me but is transmitted to the computer digitally and then stored as AVI, so I don’t think there is any degradation in the upload process. This is exactly analogous to ripping a CD to a WAV file. You can have degradation if your computer or disk drive can’t keep up with the frame rate, though.

There should not be any degradation. Atleast no more than plugging the analog to the digital cam.

It’s basically the same thing, instead of plugging the composite to the digital cam, you’re plugging it into the computer. Both then do the same thing: convert the signal to digital video.

What I mean is that if whatever format your digital camcorder uses is not lossless, then you are in effect recompressing the video when it’s converted to avi. Compressing files twice and/or converting formats ie. mpg to avi, will result in degredation. If the camcorder performs some kind of compression and you can use that file directly without converting it to another format, then there’s no problem.

Your best bet is probably to capture the video directly from the analog camcorder to your computer, probably in some kind of raw lossless format, then compress using divx or xvid.

Hmm, Eleusis does have a point, if the digital cam uses lossy compression then you’ll just be losing quality.

I second what Eleusis says. If you’re really concerned about not losing any data, a raw data capture by the computer is the way to go. You’ll need a video capture card in order to this. Of course, you will still have to deal with the possibility of frame dropping.

Your camera stores in an AVI format which is compressed but not much. Most DV cameras today have a “pass through mode” which essentially daisy chains the analog camera to the DV camera and then to the Computer input Firewire port. (Some DV cameras may work in Pass Through mode only if the tape is not present.) The video must be converted from analog to AVI at some point. If you go to the Pinnacle message boards (which are excellent) you will find discussion of this.

It’s a matter of choosing where you would like to have the conversion taken place and how much loss you get at that point. The experienced users on the above mentioned board seem to prefer using the DV pass though or a dedicated digital capture card. Pass through results are generally said to be excellent and frame drop is not a problem since the computer is not converting the signal.

First, a caveat - Read The Manual before you try this…

Depending on the capabilities of your digital camcorder, you may be able to connect the output of your older analog camcorder to the a/v connector on the digital camcorder and have it perform the a/d conversion in real time, outputting a digital signal via its firewire port which you than capture on the computer. My Sony DCR-TRV20 can do this. You will probably have to buy or make some sort of an adapter to get the connections right - the cable that comes with my camera has a mini jack on the camera end and the three standard (video, audio left & audio right) RCA jacks on the other. I have connected the camcorder this way between a VHS tapedeck and my computer, played a VHS tape and recorded the result to the hard disk.

Arrgh… how did I miss KenGR’s post? Anyway, me too.

Alas and alack, my digital camera (JVC DVM70) has no input whatsoever. It is loaded with outputs for DV, analog, still photo download, etc., but there is no way to give it analog input (although it will take digital input from another DV camera).

It will output a digital signal for live video. I guess analog input was just one feature too many. This is a very compact camera incredibly loaded with bells and whistles and I guess they had to draw the line somewhere.

So I guess my alternative is an analog video capture card.