Comments

vitalforces wrote on 6/24/2002, 9:54 PM
I don't know the resolution of Hi-8 but I am capturing all my old analog footage from my Sony Hi-8 through a little Dazzle Hollywood DV-Bridge ($300). It converts anything analog to standard DV video & audio--720x480 with 48Hz 16-bit audio--with no further degradation of picture quality, and gives amazingly good quality (by my non-network standards). Works in both directions through a firewire, meaning you can output the edited DV back onto a Hi-8 cassette, VHS recorder, another firewire device, or anything else. And has a connection for a regular TV to watch your own editing in NTSC. Once you've captured, everything stays at DV resolution from then on. I'm converting all my old analog footage, ultimately, to DVD discs. There's better conversion equipment out there but this little jeep produces a better picture than the Hi-8 itself. The only caveat is that VV3's capture utility is not that smooth reading from the DV-Bridge, so I use a Ulead capture program--until an update, perhaps VV3.0c, comes out.
SonyDennis wrote on 6/24/2002, 10:06 PM
Hi8, being analog, can't be measured in pixel count resolution. Analog video is measured "lines" and is related to the number of black/white vertical lines that can be resolved before they all blur together. I say releated because sometimes this is scaled to be per screen height, just to make it more confusing. Also, the color resolution is not as high as the luma resolution. Ultimately, you could convert this via Nyquist "twice the highest frequency" and stuff, but be assured that 640x480 or 720x480 would both be just fine for capturing Hi8. If you have other DV in the project, are using external monitor features, or are printing to DV when you're done, just use your DV camera to capture the Hi8 at 720x480 (or, if you have a Digital8 camera, all but one will play Hi8 tapes and output DV).
///d@
Mike M. wrote on 6/24/2002, 10:22 PM
Thank you both for the information. I'd love to convert the analog Hi8 video to digital (using a DV cam or converter) but for now I'm holding off because of funds.

HeeHee wrote on 6/25/2002, 12:47 PM
FYI - The Canopus ADVC-100 is a much better product than the Dazzle DV-Bridge for relatively the same price.
riredale wrote on 6/25/2002, 12:50 PM
In the NTSC analog world, "Broadcast Quality" video can deliver about 330 l/ph (lines per picture height) vertically and about the same horizontally. Like SonicDennis said, this is measured with one of those wedge charts on the screen; you see wedges of alternating black/white lines that taper towards the center. You follow the lines towards the center, and at the point where they are no longer distinguishable, you read off the resolution printed alongside. Since NTSC is 4:3, engineers back in the 1930s felt it was more meaningful to scale the number of vertical line pairs (i.e. horizontal resolution) by 0.75 so that one could see how horizontal resolution compared with vertical resolution.

Hi-8 is an analog system also, so while the vertical dimension is "pixelized" (due to the scan lines), the horizontal is not. As measured on a chart, Hi-8 comes in at around 400 l/ph horizontally.

DV is pixelized both vertically and horizontally. Take the 720 active samples on a single scan line, normalize them to the 4:3 aspect ratio, and you get 540. But you'll never see that theoretical resolution, due to something called the Kell Factor; what you'll probably measure is more like 450-500. Plenty good for Hi-8.
SonyDennis wrote on 6/25/2002, 2:50 PM
riredale:

Wow, that's encylopedic!

After I posted my "Hi8 is analog so there's no pixels" bit, I got to thinking, most modern camcorders use CCDs, which are inherently sampled, so in a way, even though the signal path and storage is analog, the original image was sampled, so for a given camcorder, there would be a "no better than X pixels per line" measurement that could be applied to it's ananlog-to-digital conversion. A wedge chart could be used to measure this as well. However, with so many systems optimized for DV, and cheap DV capture hardware like the Canopus box (or a borrowed camcorder), one might as well digitize it as DV instead of dealing with an oddball image size like 480x480 (unless, of course, you were making SVCD's <g>).

It's always a pleasure to read your technical postings.

///d@
riredale wrote on 6/25/2002, 10:52 PM
Thanks; I know a bit of esoterica (just a little bit) due to my involvement in the early HDTV standard-setting process back in the late 1980s. The company I founded was proposing an NTSC-compatible codec we called HD-NTSC, but to our dismay (and the chagrin of our backers) the feds decided to create an entirely new, incompatible format. The results of that fateful decision are now evident in the HDTV broadcast fiasco, and Congress is left with egg on its collective face for giving away $50 billion (BILLION!) in extra spectrum without any chance of reclaiming the original spectrum.

Anyway, VV is a fine product and I am in the debt of you and the other members of this board in learning all the various features; keep up the great work!
SonyDennis wrote on 6/26/2002, 12:12 AM
riredale:

You're not talking about the 1980's HD proposal where there was the regular NTSC broadcast and then ancilary side-panels (for 16:9) and resolution enhancements sent on a separate carrier, are you? I never understand why that system wouldn't be plauged with problems relating to not having 100% of both signals. I imagined some pretty weird artifacts when things aren't perfect, which of course, they never are <g>.

$50B in spectrum? From what I've been reading, the concept of spectrum being a limited resource is based on "old ideas and technology" and there's more than we'll ever need once we figure out how to do it right <g>. I'll believe it when I see it.

///d@
riredale wrote on 6/26/2002, 2:57 PM
SonicDennis:

You're referring to the proposal put forwared by Sarnoff Labs in Princeton NJ. They called their system "ACTV" (Advanced Compatible TV) and they proposed delivering a wide-screen image by delivering the center 4:3 portion in the usual way, but the extra image side panels were delivered over a second 6MHz channel. You're right; we and many others thought that it would be extremely difficult to make the panel seams transparent under real-world conditions.

Our proposal was quite different: We proposed (1) reducing the active line count down from the 483 typically used, creating a letterbox wide-screen image; (2) subsampling an HDTV image in a three-for-one pixel pattern, creating what we called subpixels as part of a process we named "TriScan"; (3) restoring I and Q color channel information out to the original 1.5MHz NTSC spec; (4) including a helper signal in the overscan to eliminate any multipath or ringing; and (5) delivering multichannel digital audio by modulating the black letterbox bands.

The result? On a cable carrying the HD-NTSC signal, you new HD-NTSC set would deliver a beautiful widescreen image with about twice the vertical and horizontal resolution, accompanied with multichannel digital audio. AT THE SAME TIME, the same signal could produce a conventional image on conventional sets, with only a small degradation due to the subpixel sampling process.

You wouldn't believe the flack we received from Sarnoff Labs and Philips. Surprisingly, the NHK engineers (the Japanese TV technology experts) were very interested and courteous, even though they had a competing system. All this took place back when Americans were scared to death of Japanese industry, which appeared poised to dominate every aspect of technology. What finally happened is that the committees were steered into first rejecting any NTSC-compatible approaches (like ours), and then forming the "Grand Alliance" to promote and develop the MPEG2-based DTV format. By doing so they stopped any further Japanese encroachment.

BTW, I think MPEG2 is terrific, and it does a fine job of data compression. My point back then was this: As a kid, I read a magazine called Popular Science. In some issues they would eagerly talk about the new "Chrysler Turbine Car." At last, here was an engine with only a few moving parts that could burn anything from kerosene to peanut oil. It weighed only a hundred pounds and put out 400 horsepower (my apologies to non-US readers, but this was back in 1960, after all). Why, the article said, there were only a few more things to be worked out, and then these cars would be ready!

So what happened? Every few years or so, another article would state that in just a few more years, all the quirks would be worked out. Meanwhile, the ancient Otto-cycle internal combustion engine just kept getting refinements (like catalytic convertors and digital fuel controls) and today, virtually all autos are powered by Otto-cycle engines. Note that it's not that turbines are bad--hey, they're indespensable for commercial aviation, among numerous other uses--but they have never been viable for cars. In the same way, NTSC and PAL, warts and all, still do an excellent job of delivering video, and these systems could be pushed much further down the development path.

Anyway, that was my speech to the feds, but it fell on deaf ears, I'm afraid.

OK. Impassioned speech over. Back to NLE.