IO-LA SC/H Phase
by Tom Matthies on Jan 17, 2008 at 8:13:20 pm
I use an Io/La for outputting to BetaSP tape at home. I always monitor my inputs/outputs on a Tek Waveform/Vector monitor.My Hamlet shows the same error. (Yes, I'm THAT much of a GEEK that I actually have a WF/VS AND a rasterizer that will display SC/H on my home editing system-sorry) While I output from Final Cut and the Io is under control of the program, I've noticed that the SC/H phase on the Io is off my scale (it goes to plus/minus 45 degrees). I can adjust the output phase using the Io Control Panel application when FCP isn't running, but I have no control over the phase when the Io is under control of Final Cut. Even if this is a little Old School, it still concerns me that the phase is that far off when making dubs for air. Is there a way to adjust this while under FCP's control? I know this isn't as important as issue as it was in the "Old Days" but I would still sleep better at night knowing the SC/H phase is within the proper limits when making tapes to send out to broadcast facilities.
Tom the Geek
Re: IO-LA SC/H Phase by Bob Zelin on Jan 18, 2008 at 2:32:03 am
you need a good beating. I want you to stop measuring SC/H phase right now. SC/H phase was critical in matching color frame linear editing systems. Color frame errors, caused by SC/H error, caused the "infamous" (not to this crowd) H-Shift (a horizontal shift) at the edit point. This occured because you were telling your linear editing system to perform a cut or "match frame" at a particular edit, but this was not in the proper 4 field sequence (so that the subcarrier would line up properly, resulting in a phase change in the color by 180 degrees), so they would SHIFT the actual video by a frame, so the SC would line up (becuase it was better to get a H shift, than to have a blue face).
WE DONT DO LINEAR EDITING ANYMORE TOM. And on top of this, your piece of crap UVW-1800 Beta VTR doesn't even have a 2 field/4 field switch, so you can't even tell your VTR to force record the color frame pulse (if you kept a BVW-75 in 2F, it would not record the color frame pulse, and you would have a 50% chance of getting the H-Shift, even if you had proper SC/H in your system.
No broadcast facility is checking SC/H phase anymore. You have a Tektronix 1750 which had SC/H measurement (in the style of a vectorscope phase indication), and this is a COMPOSITE VIDEO SCOPE TOM. You are worried about SC/H phase, and you have the NERVE to be monitoring only ANALOG COMPOSITE VIDEO ON YOUR SCOPE - AND YOU ARE WORRIED ABOUT ACCURACY !!!!
So Tom - STOP IT, STOP IT RIGHT NOW, or I'm gonna come over there, and you don't want that now, do you ?
Re: IO-LA SC/H Phase by Tom Matthies on Jan 18, 2008 at 3:53:49 am
You're right. I need help. It drives me up the wall to see that damn indicator going up into the (formally) forbidden zone. It's a disease all right. It's called "Old Timers Disease" and I have it.It comes from breathing too much head cleaner in my younger days I guess.
You're right. I have the UVW-1800 in the home edit room. I guess it's all relative. I have to remember that these spots are going to TV stations in my local market where the operators loading my spots onto their servers have most likely never even heard of SC/H phase let alone understanding it. I am amazed today at the apparent lack of even the most basic training in the art of measuring a signal correctly. Everything is either automated or it's simply ignored.
Actually Bob, I'm going to keep my scopes and even check things like SC/H phase, quadrature, and even dream of getting one of those new Tek scopes that will display the lightning patterns and be able to check gamut errors.
Sigh...good times. Good times...
I'm going to go tweak my Quad machines now....
Re: IO-LA SC/H Phase (a great OT story) by Bob Zelin on Jan 18, 2008 at 4:22:11 am
sorry AJA, but this is a great story for Tom (since he owns a UVW-1800).
15 years ago, a client in NY rented an AVID and a UVW-1800 to CBS Network on 57th St. in NY. CBS was concerned about the horrible audio meters on the 1800 (averaging meters), and felt that they were not recording the correct audio levels. I went over there with test equipment, and assured them (and showed them) that everything was correct, and the 1800 just had terrible audio meters that did not accurately show the general levels of the media (tone of course is fine on these meters).
SO, the producer is nervous, so he says "lets go across the street to Quality Control, to make sure that everything is ok". So we record a short clip, with bars and tone at the head of the UVW-1800, and take it to CBS Master Control Quality Control on West 57th St. Not even this supervising producer had clearance to enter this area.
We get in there, and it's OLD - the equipment and the employees. And this old geezer (70 years old, I'm not kidding) takes my Beta tape, sticks it into a Sony DVW-A500 (with nice peak meters, showing the -20dB full scale indication for tone), and LOOKS UP TO THE TOP OF THE RACK.
And on the top of this old grey rack is a SINGLE MONO ANALOG VU METER. And the meter creeks it way up to 0VU, and the old bag turns to the producer and me, and says "yup, its BROADCAST QUALITY".
AND NOW YOU KNOW WHAT BROADCAST QUALITY MEANS AT CBS NETWORK IN NY.
Re: IO-LA SC/H Phase (a great OT story) by Tom Matthies on Jan 18, 2008 at 4:02:56 pm
Yea, I remember when I got into this field back in the 70's. I was working at a local TV station while going to college. Great on the job training. I was all of 18 years old at the time and didn't know much about anything. Well, I'm on the job there, learning everything I can get into and I'm taken aback by the engineering staff at the station. I think that the average age there for engineers was about 120 years. Or, at least it seemed that way. Keep in mind that this was in the days where there were ash trays next to every Quad machine and in master control. I think that most of the engineers were chain smokers. As I was trying to learn stuff, I was constantly bombarded with the "Well, back in the old days..." stories. I was told about how they used to only have two black & white studio cameras and how they did live commercials during the news cast and had live booth announcers and on and on. Well, 30+ years later I find myself doing the same thing. We have a couple of editors on staff here that have never cut on any system other than non linear. They have never edited tape before. I relate what it was like back in the days of sync rolling A-roll and B-roll tapes and doing live dissolves through a switcher to a third machine. Stories of having to make a B-roll layoff reel back in the CMX days to do a dissolve since both of the source scenes were on the same tape. The day we got out first Ampex D2 deck that could do pre-read edits. It was magic! The youngsters look at me like I'm relating a story about how we went out and hunted dinosaurs for food while living in caves and grunti9ng for communication.
While I think that I actually do a pretty good job at staying current on today's technology, I do miss the "good old days" as well. Production today is just too easy to do. I'm constantly amused at the posts on the COW that seek out that magical Plug-In that does some effect that they sat on a cable show over the weekend. "Does anyone know what Plug-In was used for this effect?" they will ask, not realizing that "that effect" was probably the result of many hours of shooting, editing and compositing in a variety of programs. Many hours of very complex and painstaking work is boiled down, in their minds, ro some plug0in that will do all of this automatically. I think that all the current technology is great. I use a variety of hardware/software everyday and it's great. But I think that there is still getting to be a decided lack of basic knowledge in this business. The kids we are seeing these days might know how to edit on Final Cut or author a DVD in Studio Pro, but they cant read a waveform monitor, don't know what a gamut error is, know nothing about blanking or even the difference between 0db audio in the analog world and 0dbfs in the digital world. Last week I got in a spot from a national car manufacturer, on BetaSP, that we needed to add a local tag onto. The audio levels on the Beta were so hot that it pinned the meters on the high end. Obviously, the audio was produced at digital levels for production but it wasn't accounted for when making an analog copy of the spot. This not only made it through the production house (or boutique) that edited the original spot but also through the dub house that made the copies. Hello!! This is basic stuff here, folks. The basics still count and are necessary. Grrr...
Time to get off my soapbox and back to work.
Us old timers don't just have funny stories to relate about the business. There ate times when we do actually know some important stuff about what were doing.
Learn the basics and you will make your job much easier on yourselves in the long run. And you will make everyone elses live much easier as well.
OK, calm down and get back to work now...
Re: IO-LA SC/H Phase (a great OT story) by Tim Ward on Jan 22, 2008 at 7:01:37 am
[Tom Matthies]"The kids we are seeing these days might know how to edit on Final Cut or author a DVD in Studio Pro, but they cant read a waveform monitor, don't know what a gamut error is, know nothing about blanking or even the difference between 0db audio in the analog world and 0dbfs in the digital world." [Tom Matthies]"Learn the basics and you will make your job much easier on yourselves in the long run. And you will make everyone elses live much easier as well."
This is SO true, and is evidenced by the heaps of commercials and programming (primarily local) that are technically horrible! Safe areas, audio levels/balance, stereo/split mono, bad black levels, nice bleeding-red graphics, "you mean there's a rule of thirds?", etc...those are some of the negative effects of the "DV revolution". Not that the DV revolution is bad; it's "revolutionized" the industry for the better. It just irks me to no end how the ignorance grows!