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-   -   S-Video cable or is composite ok? (http://www.digitalfaq.com/forum/video-capture/4915-video-cable-composite.html)

JT_too 02-01-2013 07:09 PM

S-Video cable or is composite ok?
 
Hey all!

Ok, just about set to start transfering those VHS tapes to digital.

Bought a JVC-SR-V10U and an ATI 600 USB stick, now how to hook em up?

Should I go get a S-video cable of is the composite connection good enough?

Thanks for your help!

volksjager 02-01-2013 09:59 PM

s-video is better.
the cable are cheap, so no reason not to.

kpmedia 02-01-2013 10:23 PM

VHS, S-VHS, VHS-C is stored as luma and chroma separately. As such, s-video (separated video) is best.
Composite crushes together luma and chroma, and there is crosstalk. It's not at all desirable, if it can be avoided. And most times, it can be.

Use s-video. :)

JT_too 02-01-2013 10:31 PM

Great! Thank you very much for the help!

tomswift 02-28-2013 09:41 AM

Quote:

Originally Posted by kpmedia (Post 24791)
VHS, S-VHS, VHS-C is stored as luma and chroma separately. As such, s-video (separated video) is best.
Composite crushes together luma and chroma, and there is crosstalk. It's not at all desirable, if it can be avoided. And most times, it can be.

Use s-video. :)


I your remark about this a few days ago, and it's been disturbing me since. So I just pulled out my old copy Video Basics 4 by Herbert Zettl, since I remember that in there Zettl discussed the differences between SVHS and VHS. On page 227 this is how Zettle describes the storage and playback of both formats:

Quote:

Originally Posted by Zettl
S-VHS ...Y/C component signal transport, but composite when actually recorded on tape...

VHS ...NTSC composite...

On one of the insert pages (the paper is like magazine paper) Zettl further explains and shows in a picture that composite combines both the luminance and chroma into one signal for both storage and transport.

S-VHS decks do improve the color of a VHS signal, but all they're doing is splitting the NTSC composite signal into a Y/C component signal internally rather than letting it be split externally, so that it can travel along the S-Video cable. So with VHS, it is a toss-up because the storage and signal of the tape is composite.

kpmedia 02-28-2013 10:01 AM

No, that's not correct.
VHS stores the data as separate Y/C on the tape itself. It's not composite on the tape.
VCRs are composite or not -- that's why, for example, dot crawl is not present on a VHS tape when played over s-video.

If you want to learn about VCRs, I highly suggest this: http://www.amazon.com/gp/product/075...X&linkCode=as2
Great reference book, even I tend to learn a lot from it.

tomswift 02-28-2013 12:23 PM

You realize that Video Basics is, from the reviews that I've seen, the top text book used by colleges and universities (and even some high schools) in both Canada and the US when teaching broadcasting and video production? Also the book that you are referring to, I see, was also published in 1998, while I was referring to a book that was published in 2004. And I've been having trouble finding much information on the authors (and when I type in both author's names I tend to get all sorts of books by them related to paranormal activity to historical non-ficiton, but nothing about their background, aside from then being engineers). With Zettl I've been able to find out that he is a professor at San Francisco State University and that he has worked for various television stations and networks.

But from what I can see, (both using online sources and Video Basics 4), with composite it is recorded as one signal, but within that signal are two streams, slightly out of phase from each other.

Now then this is a direct quote from Zettl in regards to the Y/C Component (S-Video) system:

Quote:

Originally Posted by Zettl, Video Basics 4, Thomson-Wadsworth, page 225
Two wires are obviously needed for carrying these two signals, but to save space they are recombined when recorded on videotape. During the playback the two video channels (Y and C) are separated again.

In regards to the Composite system, he says this:

Quote:

Originally Posted by Zettl, page 224-225
The signal for composite video combines the color, or C signal (which combines the red, green, and blue signals) with the luminance, or Y signal (which consists of the black and white information). The combined C and Y signals are transported inside the VTR by a single wire and recorded as a single composite track on the videotape...this system was originally developed so that color broadcasts could be received on a monochrome receiver in black-and-white, and black-and-white broadcasts could be seen on a color receiver.


volksjager 02-28-2013 12:41 PM

for VHS transfer S-video is superior
if you want to ignore that and use composite - go ahead, but your transfers will not be as good.

honestly books are absolutely no substitute for real world experience.
im a mechanic and ive seem more "ASE certified " morons than i can shake a stick at.
they read the books, passed the tests and i still wouldn't let them work on my wheelbarrow.

NJRoadfan 02-28-2013 07:45 PM

Quote:

Originally Posted by tomswift (Post 25357)
You realize that Video Basics is, from the reviews that I've seen, the top text book used by colleges and universities (and even some high schools) in both Canada and the US when teaching broadcasting and video production? Also the book that you are referring to, I see, was also published in 1998, while I was referring to a book that was published in 2004.

Sounds like another hack who wrote a textbook to profit off of. I bet he makes his students buy the book to pass his classes too.

That being said, VHS and Betamax both write chrominance and luminance separately to the tape using a "color under" method. There is a comb filter in the VCR to separate a composite signal while S-Video (and many camcorders) goes directly onto tape. The reason you want to avoid composite is the process to separate the Y and C signal is not 100% perfect. Various methods of comb filtering have been invented over the years, but they still won't restore a signal to its full quality after being combined into a composite cable. It comes down to this....you don't want to add any more noise to your source!

kpmedia 03-01-2013 09:21 AM

Like I said, read VCR Troubleshooting & Repair, Third Edition
Those guys are reputable, and are spot-on with everything they've written. It's an excellent book.

This Zettle guy is flat wrong.
For example, luminance is not B&W. It's greenish values of light and dark (luminance). Depending on format, it holds the resolution.
However, in the quoted "pg 224-225" part, that sound like he's describing a composite-only VCR, even if he's not been clear. Not the tape.
Then again, the first quote is wrong. VHS uses color-under, as NJRoadfan explained.

I'd put that book up. It's crap.

tomswift 03-03-2013 09:22 PM

You realize that color under is a modified form of composite video; it was a compromise that still uses one signal, but two out of phase streams. By using the color under method a VCR records a very sharp monochromatic signal at the normal frequency, but then the color information gets recorded at a lower, "fuzzy" quality. As David T. Ronan mentions on page 442 of his "Practical VCR Repair", the color information is recorded at a 'down-converted' central frequency of '629 khz', and on playback the VCR has to up convert the chroma signal to 'it's original 3.58 MHz range'. And that is done by frequency modulation, not actually recording the individual channels.

And I disagree about Betamax being composite. Considering that Sony used Betamax as the basis for both of it's other component lines (Betacam and 8mm), I'd argue that it was more Y/C component (or it could be called Y/C Composite) because Sony allowed for improved quality during playback on the SL-HF2100 and the ED Beta's, and a regular Beta tape could have an improved picture when recorded on all any of those decks (through the B levels), even though the original Beta's only exported and imported in composite by the RF or RCA connector (plus a few of the early Betacam decks were were backwards compatible).

NJRoadfan 03-03-2013 11:28 PM

Color under video is still stored in a way that avoids using a comb filter.

Betamax and Betacam are completely different formats despite sharing the same tape shells and were never compatible with each other. ED-Beta was color under like the original Betamax standard but used metal tape to store the higher quality video. Even though the luminance resolution was increased, the chroma resolution was the same as the original format (SVHS is similar to VHS in this regard). Betacam (oxide tape) and its SP variant (metal tape) recorded chroma and luma on separate video tracks and are considered component formats (not to be confused with YPbPr video). Chroma on those formats has superior resolution, which is needed when doing multi-generation editing. The linear tape speeds were also faster than Betamax. Panasonic had a competing pro format that used VHS tape shells called "M" (oxide tape) and "MII" (metal tape, released to compete with Betacam SP).

tomswift 03-04-2013 07:24 AM

A VHS or S-VHS VCR needs to use a comb filter, otherwise you are going to get a lot more chroma crosstalk. Take a lok on page 186 of hat book you guys have been throwing around.

As the book says:

Quote:

Once it has been up converted to 3.58 MHz, the crosstalk component and the desired signal are passed to the comb filter circuitry for crosstalk elimination.


...it does this by taking advantage of the frequency interlaced chroma oscillation present in the composite video signal.


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