Question about exporting DV footage

[David Ho]

Ok, I know that when you input DV footage, you either use the FireWire or the USB and hook up from your camcorder to the PC. Now when you export it back, do you usually do the same and then just export back the *edited* footage or *new* footage onto the camcorder, and it should auto record over a blank new tape (preferred probably? dont want to use old tapes that already has footage), right? Or is there other ways ot putting it back into cassettes or something? What I plan to do is export some footage back onto the camcorder, then hook up the camcorder to a VCR/TV and record it in VHS (usual method of how I always record)... any other methods or is this the preffered way? I want to know which way will minimize errors or anything like that..

[Boyd Ostroff]

David, basically you have it right. Of course you could also buy a DV deck to do this, but that may be more than you want to spend and not justified if your use is light. Some camcorders allow DV pass-through, which means you send the DV to the camcorder via firewire and it passes directly through the camera and out through the composite (or s-video) ports without needing to be recorded to tape. Check your camera manual to see if this is supported and how to activate it.

Another option would be to get a firewire converter box that would perform this same pass-through function without the camcorder. I think these can be had in the $200 range but have not personally used one.

A final technique might be to send either s-video or composite video directly from the graphics card on your computer to a VHS VCR. Look at your computer and graphics card docs to see if you're equipped for this. There might be some quality issues involved with this technique however, and your editing software would also have to support a way to send video to the graphics card instead of via firewire. For example, on the Mac you could do this with Final Cut Pro but not iMovie. I'm not really familiar with the "PC universe".

Hope this gets you started in the right direction!

[Norm Couture]

David,
You have it right. Most of it.
By duplicating to VHS directly from the DV camcorder's output (S-Video or A/V), you'll get copies with 0 IRE blacks. No setup = dark copies in north-american NTSC, except if you have a pro-series camera with setup switchable to 7.5 IRE.

With no budget at all, I avoid the problem by transcoding my edited movies to highest quality MPEG2 with TMPGenc and burning it to DVD. Copies from my DVD player are better than the original DV despite the compression. DVD players add 7.5 IRE setup to their NTSC outputs, and TMPGEnc allows very fine color correction and enhancements.

[David Ho]

What are IREs? Is it bad?

[Jeff Donald]

IRE is the Institute of Radio Engineers and a predecessor to IEEE (Institute of Electrical and Electronics Engineers), pronounced Eye-Triple E. IEEE establish standards for measurement, performance etc. of electrical components. FireWire is known as IEEE 1394 for example.

A level of black video signal was established in the early days of broadcast and it is known as IRE 7.5, read as a percentage of the video signal. This is the black level required by the FCC for broadcast in the US. Levels below 7.5 IRE might interfere with other parts of the broadcast signal. This was more of a concern in the days of analog than it is today, but it is still required by the FCC. Mostly this requirement is to maintain compatibility with older hardware.

Norm, most devices add set-up (AKA black level, 7.5 IRE) at the output. You might want to check your camera if you don't think set-up is being added.

[Norm Couture]

Jeff,

Most of our consumer NTSC camcorders are built in Japan where they also use NTSC standards but with 0 IRE black level.
PAL does not suffer from this old north-american disease.

I know my Sony DCR-TRV320 cam does not add setup to its analog A/V or S-Video outputs, but my Sony DVP315 DVD player does. That's why my DVD copies look just great, but the direct output from cam to TV has the blacks crushed down. Computer screens do not use 7.5 setup. No problem in the digital world. It's only when you connect to an analog TV set or VCR.

Here's a link (taken from another forum!) to a well-illustrated explanation:

http://pro.jvc.com/pro/attributes/prodv/clips/blacksetup/JVC_DEMO.swf

[Jeff Donald]

If setup is added to analog outputs will depend on the equipment and in some cases menu settings. Adam Wilt has an excellent discussion on setup on his site here. Setup is not needed in a digital world, just for analog NTSC in North America.

Thanks for reminding me, Norm, that most (if not all) consumer mini DV cameras lack setup on their analog outs. The DVCPRO equipment I've been using at the school I teach at is not plagued with this problem.