#Video Toaster advice
10 messages in this thread
David, as Jerry and Peter pointed out, the monochrome (Y channel)
specifications for S-VHS format are superior (typically 5 mHz or 400 lines
resolution compared to around 4.375 mHz or 350 lines for U-Matic SP), however
there is a lot more to it than just getting high frequency Y information on the
tape. The quality and stability of the chroma signal along with base line
noise floor degradation is probably even more important when dealing with
multipass editing. Although there are those who will say that the 400 line
resolution specification is better, keep in mind that the top end for broadcast
is only around 335 lines, and I seriously doubt that you will see that value on
a cable system. We use the Sony BVU-950 U-Matic series for most general
purpose work and find it to be far more than adequate. Political spots would
probably be good on standard VHS <grin>, but that is only a personal opinion
(just kidding here). I am guessing that cable companies will take U-Matic SP
(based only on local information here), but one of the ones who has dealt with
various companies will have to jump in and clarify this. All my experience has
shown that the 3/4 inch is pretty much a universal format everywhere with the
three major networks going to BetaCart as the preferred format. As for the
setup with the Toaster, I'll default to Jerry on that one since he is the
expert with it in post work and I don't use one (yet, Jerry, yet <g>).
Vince
Vince,
Thanks for jumping in there with all the technical expertise! I hope David
will also heed all the warnings he's getting about dropout and generational
loss that attempting to edit in S-VHS or Hi8 will bring. I sadly remember
assuming that all the nice people that warned me about that just didn't know
what they were talking about…:( Many thousands of mistaken dollars later, I
edit on Sony 3/4 SP gear…
Jerry
Jerry, know exactly what you mean about getting burnt on the formats. We used
U-Matic for years and, on advice from a "friend", picked up on some Panasonic
S-VHS decks to see what they were capable of. Did a bit of editing with them
only to run into that "what's wrong with this??" problem. Of all things to
happen, knocked one of the B&C connectors off the TBC while doing a dupe and
noted on the freeze frame that the chroma was displaced by about four lines
which was the "what's wrong" part of the signal. Got into the service manuals
and discovered that they had designed an additional line of delay in the chroma
path to use for noise cancellation which was not compensated for in the Y
signal, resulting in a one line per field noncoincidence between the Y and C
signals. That one will drive ya nuts just trying to figure out what is wrong
with the picture until you figure out what is going on between the two paths
<grin>. The error is cumulitave through the generations, of course. When I
called their tech support number, all I could get out of them is that "the
machines are operating as they were designed to", so that did it for that brand
of equipment. Oh yes, did a bit of "redesigning" and got that extra line of
chroma delay out of there with noticeable improvement in chroma stability and
base line noise floor, but the additional noise is not objectionable and easily
cleared in either a frame synchronizer or the TBC. I use those machines for
sourcing when someone insists on providing S-VHS footage, but that's all
<grin>. Oh yes, you are quite correct about the dropouts on both VHS and Hi-8,
but I figured that Hi-8 is acceptable for acquisition. Personally, I'd rather
a BetaCam for that any day. For the real work, I agree that U-Matic SP is the
way to go unless you really need the "C" capabilities. The VHS machines are
still acceptable for time shifting Perry Mason reruns though <grin>.
Vince
Vince,
I wasted about $4K on a couple of NEC PC-VCR's, which are RS-232 controlled
S-VHS decks. One of 'em sits on top of my console, and is only used for
transferring VHS or S-VHS footage to 3/4 SP, and the other is in the lobby to
play tapes for clients occasionally…
Jerry
Vince,
Any details on the "redesigning" that you did?
Nate Wahl, Emerald Video
I am a Nate, ergo I Animate!
Nate, had to sit here and think about that question a minute <grin>. I assume
you are talking about the Panasonic machines, right? If so, I could pull the
service manual and give you specifics, but the general of it was to remove a
delay line in the chroma path, bypassing it with (I think) a 470 ohm resistor
with a 470pf bypass across it. The idea was to get the demodulated chroma back
to the same line as the luminous signal since, by design, it had been delayed
one line following demodulation for reasons unknown. Once done, the
coincidence was restored and the slight increase in chroma noise was easily
taken care of within a general purpose frame synchronizer like the Sony
MPU-F100 with a NR setting of 3 or 4 (recommend using the lowest setting to
prevent excessiving interframe averaging creating an effect similar to "lag",
which we all remember how bad that can look <g>). That was about all that was
required for the fix, however, it was actually more difficult than it sounds
because of that surface mount and "super micro" design that was used on the
circuit boards. A steady hand!
Vince
Vince,
<"excessive interframe averaging">. I've been into video for only two
years now, and you know what's really scarey? I understood that.
Thanks for the info. I've printed out the msg, and will use it for future
reference if needed. I'll leave it to a qualified tech when the time
comes.
SMDs kinda ended the DIY'er fixing things once and for all, 'eh?
Nate Wahl, Emerald Video
I am a Nate, ergo I Animate!
Nate, that averaging built into the F-100s is also one of the best features
that exists for killing noise in a bad tape (without too much motion, that is)
and for the stills that come down on the InterSats. Of course, excessive
levels can reall do strange things to a strip <grin>.
On that extra delay line in the chroma path, make sure your tech realizes that
it is the one in the playback chain instead of the record side otherwise you
will kill your Y/C separation circuitry. Actually, I would really like to see
everything go to R/G/B/S to eliminate these kinds of problems, but that step is
still a few years away for general acceptance. We have to work our way through
the MPEG fiasco yet.
Best to ya, Nate and I hope you have a really great year.
Vince
Vince,
just a quick note: you write "BNC connectors" as "B&C". Someone correct me if
I'm wrong, but there are a couple of interpretations of the BNC acronym, one of
which is British Nut Connector.
Blaq!
Charles, oops! Without thinking I did that and, of course, the reference was
to the UG-88, UC-260 type which mate with the UG-1094 connectors. Common type
of connector used on video equipment as opposed to the RCA phono types found on
consumer equipment for video/sync signals. Appologies if my reference was
confusing.
Vince