Video tape or DVD?
First, an overview of an experiment I just completed concerning moving video to computer: First I tried it my standard way and ran the video output from a video camera into the video input of a combination VCR/monitor and video taped a couple of minutes of test footage. I then played the video tape video signal into an Analog to Digital converter and captured the video signal on my iMac using iMovie. I was then able to edit the video and export the results in various formats that could be posted to the web or emailed. That done I then ran the same camera's video into a DVR and out to a monitor (as you probably know, in both cases the monitor was in the system so I could see to focus the camera and view what was being recorded). I then put a DVD-R disk into the recorder and recorded a few minutes of test footage. Next I removed the disk from the DVR and inserted it into the iMac and used a free program called HandBrake to convert from DVD format to MP4. Once that was done I imported the file to iMovie and, as before, was able to edit and export the results in various computer formats. In the end the results of both methods looked pretty much the same. So here's where I seek your opinions. Both techniques required manually converting the recorded signal into a format the computer could recognize. That being the case, is there any advantage to recording on a DVD as opposed to video tape (ignoring the facts that DVRs cost more than VCRs and that video tape is probably on its way out)? Thanks for your thoughts, Patrick
That being the case, is there any advantage to recording on a DVD as opposed to video tape (ignoring the facts that DVRs cost more than VCRs and that video tape is probably on its way out)?
They're both problematic, but in different ways: In the case of video tape, you're probably hurt by resolution. There's a great deal of variance from recorder to recorder, and you could fairly easily end up with a recording of only 300 lines resolution or so. And of course there's always generational degradation (tape to tape) with the noise buildup and loss of signal on each pass. Good equipment, good calibration and head cleaning can help. Recording onto a DVD brings up the problem of data compression. A DVD holds only about 4 gig of data, whereas the uncompressed video for the same amount of time may require 10 times that storage. In order to squeeze things in, 90% of the data are thrown away. This compression uses deep knowledge of human perception so as not to throw away anything "important". All in all, it works exceptionally well. But a DVR must do this compression in realtime, as the signal comes in. If you've done video on a PC, you've noticed that the best compression runs much slower than realtime. Good video compression on my dual G5 runs at about 3x realtime or so. All this means that the compression algorithm in the DVR is built for speed, not for quality. The places where you're most likely to notice artifacts will be in areas of solid color, with subtle gradients (nebulae?) and perhaps sharp points (stars or limbs of planets). And of course the clincher is that you're going to edit this video. That means you're going to uncompress the compressed video, edit it and then RECOMPRESS it. I use a converter that outputs files in an uncompressed format (a Canopus) that allows me to defer compression until after editing. You should investigate your converter to see if it can do this. You'll have to reserve considerable disk space in your computer, but it's worth it. You get better video, considerably better compression and only a single pass of compression. On a Mac storage for an hour's worth of uncompressed video and temporary storage to generate a DVD of the result will run 20-25 Gigabytes. MC Michael Carnes MichaelCarnes@earthlink.net home.earthlink.net/~michaelcarnes
Thanks for your thoughts, Michael. Two things I did not mention in my initial post on the subject were that the DVR set up is bulkier and that the DVR requires 110 VAC, both of which make field use a bit more difficult. So I was already leaning toward staying with the VCR anyway. The reason for even trying the DVR was a salesperson's assurance that I'd be able to record straight to the DVD and then edit the video from the DVD in my computer without doing any conversion. Obviously he was wrong. Your comments about compression make a lot of sense. So I'm sticking with the VCR for now. Anybody want to buy a nearly new DVR? Used only once. :) Patrick Michael Carnes wrote:
They're both problematic, but in different ways:
Michael, what are your thoughts on the solid-state, direct-to-memory type camcorders? What are the advantages/disadvantages there? --- Michael Carnes <MichaelCarnes@earthlink.net> wrote:
They're both problematic, but in different ways:
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Well Chuck, I haven't had any thoughts since I haven't been paying attention to the market. From your question, I assume you mean camcorders that record to Compact Flash, Memory Stick or whatever. I I just jumped onto Amazon for a sec to see what was on offer and found a few. As an example, there's a Sanyo that claims to record 21 minutes on a 1 Gig SD card. Can't say I'd be interested. Here's why. The stuff is going to be very highly compressed to squeeze onto a card. It will have to decompress and recompress to put those 'priceless memories' onto DVD. Cards are expensive. If you're going on a vacation and plan to shoot a lot of footage, you're going to have to buy a lot of very expensive cards. OR you're going to have to drag along a laptop to dump the video onto. That's kind of a pain. If said laptop fills up, you're going to have to backup the stuff to a stack of CDs or DVDs. Don't know about you, but I'm tired when I get to the hotel. Backing up a computer is one of the things I go on vacation to get away from. Compare that to carrying along a handful of DV tapes. They're cheap, hold a lot, and aren't compressed. These cameras appear to be built for convenience rather than ultimate video quality. There's certainly nothing wrong with that, as long as convenience is your driving criterion. Battery life is probably a lot better, since there's only a zoom motor to control. I'm sure that--all things considered--they're rather nifty toys that take pretty good movies. But I tend to move slowly on new technology (funny thing for a technologist to say, I guess). I tend to wait a little--or a lot--longer and buy something a little nicer. I STILL don't own a camcorder. MC
Michael, what are your thoughts on the solid-state, direct-to-memory type camcorders? What are the advantages/disadvantages there?
--- Michael Carnes <MichaelCarnes@earthlink.net> wrote:
They're both problematic, but in different ways:
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Michael Carnes MichaelCarnes@earthlink.net home.earthlink.net/~michaelcarnes
Thanks, Michael. My camcorder is 14 years old, purchased as a concession to spousal pressure when our daughter was born. The Jupiter/SL9 footage was a bonus, the result of a rare moment of inspiration. No matter what equipment I upgrade to, it's bound to be the format that the industry rejects six months later... --- Michael Carnes <MichaelCarnes@earthlink.net> wrote: __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
participants (3)
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Chuck Hards -
Michael Carnes -
Patrick Wiggins