A quick Pioneer LD player question (1 Viewer)

[Peter M Fitzgerald]

Did the industrial model, Pioneer CLD-E2000 (circa 1994), really have digital field memory for CLV trick play?

I've seen a source or two that claims it did, but another claims that it was nearly identical to Pioneer's consumer model, CLD-S201, which looked like it didn't have the digital field memory feature.

 

[Philip Hamm]

I don't know if that's the model, but one of the Pioneer industrial models not only had digital field memory for CLV, but it had full field for that function. Usually it's just 30 lines (of the interlaced 60) that you get.

 

[Leo Kerr]

er, it's a full frame of 480 lines, not 240 lines, and the model is the LD-V8000. (LD-V800 in Europe.)

Leo

 

[alan halvorson]

I am not familar with the E2000, but if it's about equivalent to the S201, it's not likely it had digital field memory. Pioneer only included this on their most expensive models.

 

[ChristopherDAC]

I think this is the El Cheapo "educational" model. Their main purpose being to show "film-strip" type videos and play back CAV programmes with limited interactivity, few educational models had any special features at all save occasionally a barcode reader.

 

[Rachael B]

If you want trick play, think Panasonic. The LX-1000U and LX-900 both have Digital Field Memory, Strobe, Art ( 3 levels of "paint"), and Multi Speed.

I aggree with Christopher and Alan that 'E' machines are guaranteed vin ordinare, or worse.

 

[Vader]

OK, I'm confused (no big suprise there...)

I thought NTSC LaserDisc was limited to 425 lines of resolution, and that DVD had 480. I'm assuming that both of these are vertical figures. Obviously, I am mistaken (also no big suprise). Could somebody make this clear for me? Thanx!

 

[ChristopherDAC]

OK, video works like this. The deflection yoke in the camera tube moves the electron beam left to right 525 times in one 30th of a second, during which time it also moves from top to bottom twice. This gives rise to two interlaced fields of 262.5 lines each. Now, as long as the proper timing relationships are maintained, the vertical resolution will be fixed; since about 20 lines per field are blanked out to allow the electron beam to fly back to the top of the screen, there are about 240 visible lines per field [exactly 480 lines per frame for digital systems]. Thanks to the so-called Kell Factor which limits the accuracy of discrete sampling systems, the effective vertical resolution is about 360 lines per picture height; that is to say, if you have a card ruled with white and black lines in front of the camera, and you zoom out, they can be reliably distinguished until there are 180 black and 180 white lines in the frame.
Now, the horizontal resolution, the number of black and white lines which can be distinguished across the screen, is determined by the bandwidth of the system, the highest frequency it can pass. You can see that this is so because a black element next to a white element represents one alternation of the electrical signal. The 4 MHz of NTSC television allows for about 480 lines to be distinguished across the screen, or 360 lines per picture height for an aspect ratio of 4:3, about the same as the vertical resolution. LaserDisc provides about 5 MHz of bandwith [played back through a good non-MUSE player], which is sufficient to provide 425 lines of resolution per picture height equivalent [or 567 lines per picture width], which is enough for decent anamorphic playback. DVD provides, by spec, up to 720 luminance lines per picture width, but in practice is often limited to about 5.5 MHz.
Clear?

 

[Vader]

Thanks, Christopher!

It will take some digesting, but that does straighten out my understanding...

 

[Leo Kerr]

One of the major problems I've always had was with the nomenclature used.

NTSC has a finite number of scan lines that any NTSC device will output: be it the cheapest piece of crap VHS VCR, to the highest of the high end D-5 deck playing NTSC: it must have 525 horizontal lines, 480 of which are 'active,' as described above.

It's when they get into 'resolution' that they start talking about a different kind of line: vertical lines. And worse, that's what they're calling horizontal resolution.

It's a naming mess.

Again, NTSC allows for 720 'lines' - or really, I prefer 'dots per line.' To make matters worse, those 720 dots are not square. Their 0.9:1 aspect ratio makes it more-or-less match a PC's 640x480 square pixel map.

The resolvable dots in the line are where you really get into resolution issues as described by ChristopherDAC above; the Kell Factor mentioned above is not something you have any control over, really; it's generally 'applied' by the cameras or otherwise very early in the production process (also called 'vertical pre-filtering,' and is used to reduce interlace based flicker.)

Leo

 

[ChristopherDAC]

There are a few exceptions. Early Sony [CV-series] 1/2-inch video tape recorders actually recorded only one field and threw the other one away, playing back with two heads to repeat the one recorded field, so the format they put out was really something like 262.5/60 progressive. This is "close enough" that an NTSC TV will usually display it, though it looks terrible. Older video game consoles are the same way. The digital field store in most LD players with CV trick effects does something similar, but with much better results [thanks to a synthetic time-base and other refinements].
From reading the early authors on television, from before vertical filtering was possible, I get the impression that the true "Kell Factor" results from the scan lines not necessarily aligning with the picture detail, which reduces the dependable resolution of the system by about one over the square root of two [while the best-case resolution remains the same]. The very same effect [phase-amplitude intermodulation is the only name I have for it] is responsible for the improved "transparency" of digital audio with a sampling rate of 60 kHz as opposed to 44.1 or 48 kHz when recording signals band-limited to 20 kHz.
Deliberate vertical prefiltering is another thing, and a true abomination. Particularly in this age when it seems everybody and his brother-in-law has some kind of deinterlacer or EDTV, there is no excuse for it at all. I routinely watch Pioneer LDs recorded with no respect whatsoever for interlace artefacts, and I have to say that they haven't bothered me yet. In fact they are scarcely noticable, certainly less so than picture softness.