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Need info on OLD equipment

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Scott Bush
Need info on OLD equipment
on May 2, 2009 at 3:17:30 pm

Hello,

At work I was tasked with digitizing a drawer full of old 3/4" tapes. To do this, I have a sony Analog to Digital DV converter box (going to a quad G5 with Final Cut Pro) and 2 old sony U-Matic decks. One is a multi-standard, and one is NTSC only.

Since some of the tapes are PAL I first tried to connect the multi-standard machine. I got perfect audio, but the video had the colors all off and wavy lines thru the image. My first thought was that I needed a TBC, so I located one and a black burst generator and set them up. Now the image was black and white. I asked one of the tech guys for help, and he told me that the multi-standard machines use a "different NTSC signal" (his words) and I'd need to use the NTSC only deck with the Sony converter box. To illustrate this he replicated the issue with a multi-format VHS player.

After some messing around I was able to get the VHS player to work by "forcing" it to one of 2 different NTSC signals (I forget the names of them but they had different numbers) instead of 'auto' - and it worked perfectly. But I'm confused aboutt he different NTSC signals. I had heard of (I think) NTSC-J before, but it seems weird that a multi-format player would use a non-compatible signal.

I guess I'm looking for a quickie education on this stuff... I know it is complex and probably a bit much for a forum, but if someone could point me to some info on the web I'd appreciate it. This may well be the last time I ever have to deal with this, but I still would like to fully understand what I am doing - I'm just that kind of guy. While I'm at it, I could use a refresher on exactly what it is that black burst generators and TBCs do as well, as for the last few years all of my tape decks have had them built in, and I haven't really had to worry about it (besides that I'm really more of an editor and motion graphics guy anyway).

Thanks in advance for any assistance.

Scott


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Bob Zelin
Re: Need info on OLD equipment
on May 3, 2009 at 12:07:49 am

Scott,
I assume that you are young. Back in the stone age, when people used 3/4" VTR's, people were willing to spend 10 times (no, 100 times) the amount of money to do "marginal" work with 3/4" VTR's.
3/4" VTR's, required time base correctors or frame synchronizers to get them to lock up to "modern" systems. Your black generator means nothing. TBC's locked to house black, but then sent subcarrier, advanced sync, and drop out pulse back to the 3/4" VTR. This means that if you have an old BVU900, BVU950, BVU800, BVU820, or even a Sony VO9850 or VO9800, it had external sync (for advanced sync, not black), and external subcarrier. If you have a "cheapie" VTR, like a VO 5000, this had not external reference ports, so you would have to use a Frame Synchronizer.

VTR's used to cost $12000, and TBC's would cost $10,000. ("what" - you now say !). And for all of this money, the only way to get them into PAL would be go thru an expensive standards converter. If you had a PAL 3/4" tape, you would have to have a PAL VTR - more money. In these days of multi format products, it's a miracle, but for those that don't remember the old days, they can't even conceive of the amount of money we used to spend to do the simpliest things.
When we say that it used to cost $250,000 - $500,000 to build an editing room, we are not kidding.

If you have a crappy 3/4" VTR (which I bet you do), you will need a frame sync tbc to lock up the VTR. The cheapest one I am aware of is the Datavideo, and the next cheap one is the Hotronics.

Sony 3/4" machines would break. They would develop subcarrier problems, which would give spinnning colors, or b+w images. Being a maintenance guy for 3/4" repair was a very profitable business at the time. Your 3/4" VTR may simply be broken. Everyone is so accustomed to stable equipment these days - they have no idea of what it used to be like, when equipment needed service on a regular basis.

You silly little DV converters and tri standard VHS machines are going to do nothing for you. Without a frame sync, or the proper TBC for your specific VTR, you are screwed.

If you were to tell someone in the late 70's or early 80's that you wanted a professional piece of video gear for $250, they would just laugh at you.

bob Zelin




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Scott Bush
Re: Need info on OLD equipment
on May 3, 2009 at 12:44:06 am

Hi Bob, I think you're making several assumptions about me...
First, I'm not THAT young, but not old either - I'm 31 - so I have some experience with tape to tape editing and did some live sports tape operating in my early 20s - mostly beta and digibeta, though (and EVS but that's neither here nor there)... I understand the very basics of TBCs and such, and am no stranger to tape decks (even still) that cost in the 50-60,000 range - maybe even more. I work at a post house in NYC - I'm just more of an editor than a tech - but I know my way around a huge variety of VERY expensive equipment like HDCAM and digibeta decks and the like.

The point here is to get these very old and deteriorating 3/4" tapes digitized and placed on our company extranet - probably in MPEG1, so the quality isn't THAT important... hence the DV converter box - we don't need to tie up profitable systems for this, we're using our 'toys'. I'm not sure of the model numbers of the decks as I am home for the weekend, but fact is once I used the NTSC-only deck with the TBC, it worked like a charm - even through my "silly" DV converter.

My main question was about why the NTSC-only deck worked, but not the multi-standard -- 3/4" OR VHS. As I stated, the tech who helped me mentioned something about the multi-format (PAL/NTSC/SECAM) decks using a different NTSC signal than the NTSC-only deck. EVEN the VHS deck worked, but only when I took it out of auto mode and FORCED it to use a specific NTSC (it had two options for NTSC, I don't recall specifically what they said). but BOTH VHS and 3/4" multi-standard decks gave the SAME exact bad signal. I should note that they both work just fine straight to the monitor - it is only through the converter box that I get the problem. This leads me to believe that the tech was right - the 3/4 in multi-standard deck uses an NTSC signal that is not compatible with the NTSC DV box, and the VHS defaults (in auto mode) to this same incompatible signal. I'd like to know why - and what the difference is between these two variations on NTSC. The use of the VHS deck was to further illustrate the existence of the "variations" on NTSC. I'm trying to get my head around the two flavors of ntsc.

Thanks for your response, Bob, your time is much appreciated; but I think you misunderstood what I was asking.



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cowcowcowcowcow
Bob Zelin
Re: Need info on OLD equipment
on May 3, 2009 at 7:04:32 pm

My main question was about why the NTSC-only deck worked, but not the multi-standard -- 3/4" OR VHS. I'd like to know why - and what the difference is between these two variations on NTSC. The use of the VHS deck was to further illustrate the existence of the "variations" on NTSC. I'm trying to get my head around the two flavors of ntsc.


REPLY -
you asked - here is your answer - and I will assume any damn thing that I want about you. I'm from NY too.

Bob Zelin


NTSC-M
Unlike PAL, with its many varied underlying broadcast television systems in use throughout the world, NTSC color encoding is invariably used with broadcast system M, giving NTSC-M.


[edit] NTSC-J
Only Japan's variant "NTSC-J" is slightly different: in Japan, black level and blanking level of the signal are identical (at 0 IRE), as they are in PAL, while in American NTSC, black level is slightly higher (7.5 IRE) than blanking level. Since the difference is quite small, a slight turn of the brightness knob is all that is required to enjoy the "other" variant of NTSC on any set as it is supposed to be; most watchers might not even notice the difference in the first place.

The NTSC 4.43 system, while not a broadcast format, appears most often as a playback function of PAL cassette format VCRs, beginning with the Sony 3/4" U-Matic format and then following onto Betamax and VHS format machines. As Hollywood has the claim of providing the most cassette software (movies and television series) for VCRs for the world's viewers, and as not all cassette releases were made available in PAL formats, a means of playing NTSC format cassettes was highly desired.

Multi-standard video monitors were already in use in Europe to accommodate broadcast sources in PAL, SECAM, and NTSC video formats. The heterodyne color-under process of U-Matic, Betamax & VHS lent itself to minor modification of VCR players to accommodate NTSC format cassettes. The color-under format of VHS uses a 629 kHz subcarrier while U-Matic & Betamax use a 688 kHz subcarrier to carry an amplitude modulated chroma signal for both NTSC and PAL formats. Since the VCR was ready to play the color portion of the NTSC recording using PAL color mode, the PAL scanner and capstan speeds had to be adjusted from PAL's 50 Hz field rate to NTSC's 59.94 Hz field rate, and faster linear tape speed.

The changes to the PAL VCR are minor thanks to the existing VCR recording formats. The output of the VCR when playing an NTSC cassette in NTSC 4.43 mode is 525 lines/29.97 frames per second with PAL compatible heterodyned color. The multi-standard receiver is already set to support the NTSC H & V frequencies; it just needs to do so while receiving PAL color.

The existence of those multi-standard receivers was probably part of the drive for region coding of DVDs. As the color signals are component on disc for all display formats, almost no changes would be required for PAL DVD players to play NTSC (525/29.97) discs as long as the display was frame-rate compatible.





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Scott Bush
Re: Need info on OLD equipment
on May 3, 2009 at 9:28:19 pm

Thanks a whole damn lot. :)



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