6. mistakes I've made

Thu - January 12, 2006

Watch out for cheap analog pro video mixers!

You have maybe seen cheap pro analog video mixers for sale on ebay or elsewhere for knock-down prices.
Just be careful that you know what your are bidding for/buying...

There is no question that pro analog video mixers of the kind that used to grace broadcast studios etc. seem a very attractive option secondhand. They usually have far more inputs than the prosumer models and have nice chunky BNC connectors etc.

BUT.... there is a big gotcha that will bite you on the bum if you think you can buy one of these and just wire up some prosumer DV cams and be mixing away.

Almost all of these mixers do NOT have any kind of frame synchronisation or timebase correction built-in.
To put it another way, they assume that all video sources are already genlocked or synchronised and that they can happy mix between them without worrying about whether all the start of frames happen at the same time.

So...they will NOT work with your average DV camcorder or indeed any other video source that does NOT have a genlock input to allow frame synchronisation.

Of course if you have studio cameras or VCRs with a genlock input you CAN wire it all up to use one of these mixers, but I would suggest that unless you are setting up a permanent installation that this is all a major pain in the neck and should be avoided for VLOBLIVE gigs.

Just stick to a prosumer mixer like an MX50 or an MX20 or the new generation Edirol ones that have frame synchronisation built in and you will be fine.

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Fri - May 21, 2004

DVD perils

The advent of DVD burners on many PCs and Macs used for video editing means that more and more video clips used in live events are being provided on DVD. It is a convenient, reasonable quality format with random access for clip selection and a menu system to allow multiple clips to be put on one DVD disk.

There are, however a few gotchas that can trip up the unwary. Here are some that we have encountered.

Here are three traps to catch the unwary...

1. PAL vs NTSC part 1

We have had several clients turn up with DVD-R disks with their clips, only to discover that the disks are encoded in NTSC format, and although they will play OK on the DVD player, they won't work through our Panasonic MX50 (PAL only) video mixer.
The culprit in all cases has been the default of the DVD burning software that was used. Most software defaults to NTSC, and you need to go in and change the setting BEFORE you author your disk. Of course the reverse is true if you live in the US or elsewhere in the world. Don't assume that because someone has a DVD it will be the right TV format
In this particular case we were forced to abandon the MX50 and use a switcher instead and run the projectors in NTSC also.

2. PAL vs NTSC part 2

We have also had clients turn up with commercial DVDs, unaware that the DVDs in question have been sourced from the USA and are NTSC format. This is trickier to deal with, as the material is often copy protected and it is not possible to (legally) transfer it into a PC or Mac for conversion to PAL. The best solution for this is to purchase a DVD player that has built-in NTSC-PAL conversion (or PAL-NTSC in the US) so that you can cope with anything.
Note that most DVD players will PLAY the other format, but they won't convert it, and are relying on ALL the downstream gear to cope with that.

3. Format wars

The next hurdle is recordable DVD compatibility. There are no less than five recordable DVD formats:
DVD-R (DVDdashR) DVD-RW, DVD+R (DVDplusR), DVD+RW, and DVD-RAM (which is for data use only)

The general consensus is that DVD-R is the MOST compatible with standalone DVD players and that DVD+RW is the least, but results are very variable. The BEST bet is to try the disk in the machine you plan to use BEFORE the event. Otherwise make sure you buy a player that has explicit support for all formats.
Ironically, the cheaper the machine, the more compatible they seem to be, (I guess the cheap chipsets are the newest) so the best backup would be to have your main DVD player and they buy a cheapo one as a backup.

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Sun - October 26, 2003

The things you wish you'd remembered before it was too late

I now make it a rule to write a 'things still to do' list as I go through the setup of a show. I didn't always...

I started noticing a trend in events I did. I would get past the first rush of setup and get everything pretty much in place. Screens up, projectors up, wiring run, PPU working, cameras in place, but then there would be a long list of little wee tasks to do - you know the kind of thing:

- check projector focus once screens have settled
- check projector colour settings
- check camera white balance
- adjust scan converter screen positioning
- check all sightlines for cameras
- tape down cables
- label inputs at back of PPU
etc. etc.

I would spend the rest of the time prior to kickoff remembering, then forgetting, then being in the wrong place to do anything about them, then being in the right place, but forgetting again, until eventually the show would start and It would be down to chance whether I had got them all done.

Then I got sorted, and got in the habit of writing down a list, right after setup of all the things that had to be done before the start of the show.

Then when someone shouted "can we open the doors?" I could immediately see what, if anything was left to do.

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faulty gear - avoid the recurring nightmare

Finding a faulty cable or connector or input etc. is very annoying. Forgetting about it and having to find it over and over again is even more annoying. Some tips for preventing this...

It's bad enough to find a faulty cable or connector in the middle of a show, but if, like me, in the heat of the moment you forget to mark it, then you are doomed to keep having problems again and again until you isolate it and at least quarrantine it, or best repair it.

The easiest and most obvious way to identify a potentially faulty cable is to wray PVC tape over one end of the cable, so that it covers the working part of the connector. This way, someone would have to remove the tape to use the cable, and if you make sure all your crew know that taped connectors are to be avoided.
It's even better if you can use white tape and write on it the nature of the fault (no video, interference, etc) to make diagnosis easier later.

If you don't have any tape to hand, then at least tie a loose knot in cable, till you can find some tape. This is not as good, as someone could untie the knot, or cables can knot themselves, but it is better than nothing. Remember not to pull the knot too tight, as you will damage the internal conductors.

The same applies for inputs or outputs on equipment, Tape some PVC tape across input/output or tape over the faulty control, to prevent anyone using it.

Another suggestion is to have a box for faulty stuff, so that it automatically gets quarantined at the end of the show.

Also remember to make time to fix it or replace it, as it is just as bad if you get to the next show without it, and are short of one cable to finish the setup.

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Thu - September 11, 2003

Where to locate your PPU - it's not as obvious as you think.

If you are setting up for a VLOBLIVE event, one of the questions you will be asking (preferrably before you actually arrive) is where to locate command central, a.k.a. your "portable production unit" PPU a.k.a your pile of gear. I am referring to the place where you (or one of your crew) will sit to play tapes, mix video, and generally do the biz for the video. I suggest the best place might not be where you would think.

It's not a trivial question, since, as we will see, it can have a significant effect on both the ability of the operator to do their job, but also on the quality of the resulting video.

In the beginning, I folllowed the obvious route of putting the PPU next to the FOH mixer, out in the auditorium. I guess I reckoned it would give me a good view of the stage and the screen(s) and there was some company if I got lonely!!. It also made audio cables to the FOH audio mixer nice and short.
Trouble was it made almost every other cable far far longer than it needed to be.

We used to spend hours on end coiling up BNC coax cables after gigs, which we had to run up and down the venue to get all the signals where we needed. Then I thought about it properly.
Where were most of the video sources that needed cabling TO the PPU?
Well, in the case of live video, they were from cameras on or near the stage. There was sometimes one camera out in the auditorium, but only one or two, versus maybe three or four onstage.

Where did my projectors usually end up? Usually at the back, or above, or just in front of the stage.
Almost never at the back of the auditorium (I couldn't afford projectors which had that kind of lensing - still can't) And the projectors were always cabled with double coax for Svideo (another story), so they counted twice in the cable count issue.

Then there was the signal quality issue. Even if you have the gear to boost signals before you run them, the general rule that shorter cables means better quality still applies. You should be trying to reduce cable length to improve quality.

So on a purely practical "how many cables am I going to need to hire/uncoil/coil" question, as well as a "how do I maximise quality?" question you want to put the PPU where it will minimise overall cable length, and quite often this ends up being at the side of the stage, or behind the stage, or under the stage (really!).

Here's a picture of our PPU set up to the side of the stage in the Queen's Hall in Edinburgh. Plenty of space to spread out all the gear.

Conveniently, on bigger gigs there is often an audio monitor mixer at the side of stage, so you can plonk yourself close to that and you won't even be on your own. (or pick the opposite side if you need to keep out of the way on a cramped stage)

This also means there is a nice ready-made way of getting audio from the stage back to the FOH audio mixer; you can just use a DI box and plug straight into the audio multicore that will be lurking close to the monitor desk somewhere!!

Draw out (or think through) what length of cabling you would need to get to the PPU from all it's possible locations, and pick the one that gives the best compromise between minimising cable length and meeting the other requirements of the gig.

My other concerns were seeing the screens and seeing the action onstage.
You may think that being able to see the screens is not essential if you have a video monitor set up as a program monitor but the danger here is the difference in contrast ratio and brightness between most video monitors and most projectors used for VLOBLIVE events.
You can mix a show (as I have done) that looks great on the video monitor, but is almost unviewable on the projector, due to poor contrast or lighting spill or ambient light levels or whatever.
Remember though that if you are using back projection screens (and you should have a good reason NOT to be using back projection) you don't have to be in FRONT of the screens - you could be behind them (this is a very common approach for corporate gigs, for the PPU to be behind the backdrop of the 'stage' with a reverse view of the back project screens)

Seeing the action onstage

This can be critical, when you are directing the shots on comms, as if you can't see the stage at all, you can only go on the shots the camops are giving you. You don't know what you are missing.

Here's an example of a less obvious PPU location - underneath the very ornate marble pulpit in St Cuthbert's church in central Edinburgh. This was the only place that I could see both the screen, at the back of the chancel stage and also the action onstage. Also I couldn't resist the absurdity of it all.

If there is no position that lets you see the stage and also minimises cable lengths, consider using an old/dodgy camera as a locked off wide shot of the stage, going to a spare monitor or TV, so you have an overview of the action. Of course, you wouldn't even THINK or using that shot in your IMAG mix would you?...

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Tue - September 9, 2003

Handheld camera work - just say no!

Hey, look at us! We have cameramen wandering around the stage, just like at Glastonbury!!
Sorry. Not impressed. ...

Question: What is the number one turn-off for VLOBLIVE video?
Answer: shakey handheld camera work that makes everyone seasick.

It just isn't 'cool' to use a tripod, or so it seems judging by the number of folk who attempt VLOBLIVE video with a couple of dodgy camcorders wielded by inexperienced camops who's only training was watching the Blair Witch Project a few times.

I know you see it at 'proper' live events, and on TV, and on your DVDs of live concerts, but there is a big difference. Talent. These guys are trained cameramen, who spend their working life getting good at doing handheld (or shoulder mounted) camera operating, and learning all the health and safety rules that make it a safe thing to do on a busy stage. They also have backup; A cable-basher colleague to make sure they don't get in a tangle; Intercom connections to the director to hear what is going on; an engineer back at the PPU, to do all the fiddly camera adjustments for them, so they can focus on focus (!) and keeping safe etc. etc.. Don't forget that, even at these rarified levels, these guys will have rehersed a lot of the shots. When was the last time, at a VLOBLIVE event, you had time to rehearse camera moves with the band, so they knew what to expect?

So you need to be pretty sure you know what you are doing before attempting this at a VLOBLIVE event.

Well it may not be cool, but the tripod is your best friend. It will make all your video more watchable, and it will anchor your inexperienced camops in a safe place, out of harm's way, as they learn the ropes.
With some imagination you can pick some pretty creative tripd positions, that will get you almost all the shots you would get from an experienced mobile camop.

Of course, if you DO have an experienced camop, then you are fortunate indeed, but there are still some basic rules to follow:

- check the stage layout for trip hazards

- walk through the shots with the camop, planning how they will get from one to the next.

- Keep the amount of moving to a minimum

- think about cable management carefully; where will spare cable live? do you need to anchor the cables to the camera to prevent damage? Do you need to have a cable basher person to prevent tangling? etc.

- don't expect a camop to go handheld for a whole show. Give them a rest, or better still a tripod as well!!

- don't hold handheld shots onscreen for extended periods, as this is quite stressful for the camops.

And finally, don't forget to ask the artists whether they are happy with wandering cameramen. At these kinds of events many have had bad experiences with inexperienced crews and will specifically request no cameramen on stage!! Ultimately it is more important that the artist is happy than that you get your 'prize' shots, so you have to go with that. I have never had anyone object to some carefully placed tripod-mounted cameras and camops.

My own experience is that I generally avoid using handheld camops if I can (I favour static cameras to get those hard to get shots), apart from one of our team who just happens to be an experienced BBC cameraman, and even he gets a tripod position to use some of the time.

Just say no. Your video will generally look better.

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Mon - September 8, 2003

The curse of the wide shot

Wide shots are for TV. They have no place in true IMAG ...

There is a great temptation, as you stare at the monitors at your control point to only think of live video as being like TV, then of course you will want to include some nice wide shots to set the context etc.
But, if your audience can already see the stage, you are only showing them what they can already see with their own eyes, so it is pointless and distracting.

You have to think THEATRE, not TV. What can they not see themselves? What will enhance their viewing from where they are?

A simple rule of thumb - if the person is the same size on the screen as they are in real life, you are not doing IMAG and the shot is a waste of time. It's not called Image MAGNIFICATION for nothing.
If you find you can ONLY get people the same size or close to real life then either your screen is too small, or your cameras are too far away, or your camops are not using the zoom, or a combination of all the above.

The complication, of course, is if you are trying to do IMAG and TV at the same time, i.e. if you are recording the show, or are filming for a spill-over room or a webcast or similar.
In this case there is a direct conflict between the need of the local audience and the needs of the remote audience. The best solution is to do two separate mixes on two separate mixers fed from the same cameras, and to add a 'wide cam' option for the remote mix only.
The next best thing is to mix the cameras separately from any song words, and when the song words are on the imag screen you cut to wide shots on the cameras and use that feed to go to tape or the remote location. This falls over if the remote location need words too.
Finally, if you have to you can feature an occasional wide shot in an IMAG feed if it is shared with a remote location.

The only exception to this rule is if you are short staffed and are very limited in the shots you can mix between and you need a 'safe' wide to go to when you have nothing else, but in this case you should really go for a safe mid shot rather than a true wide.

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Tue - September 2, 2003

Doubling up projectors - but how to control them?

I thought I was being clever doubling up our Hitachi CPX995s for extra brightness, till I tried to use the remote...

It is common practice with proper projectors to stack them for extra brightness. You can often see two, three or even more projectors stacked up all optically aligned with clever offset adjustment lenses to project onto the same screen.

Well I thought I would try the same trick with our CPX995s - place them together on the lighting truss and use their fabby horizontal keystone correction to get them aligned on the same screen. A great plan until I started trying to adjust them with the remote. Of course the remote control was received by both projectors, so they both adjusted at the same time. As I tried to keystone one to match the other, both of them adjusted together!

The solution, of course is to whack an RS232 cable into one of them and adjust it from a laptop using the Hitachi software (and tape over the remote IR input windows??), but at the time the two projectors were 20 ft up in the air and I didn't have any wings, so I had to abandon that plan.

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Multipin camera connectors - fiddle at your peril

It may seem tempting to roll your own multi-way camera cable to plug onto that big fat multiway connector on your studio camera or camcorder, but beware...

If you have ever explored the cost of buying proper multiway camera multicores you will know that they are EXTORTIONATE. The keen VLOBLIVE techie may think (as I did) "aha, I don't need all those cores and all those video signals, I just need power and video. I'll make my own DIY camera cable instead and save megabucks".

Well, you can think that, but the reality is far less appealing. There are several reasons why this is a bad idea.

1. The connectors themselves are extortionate too!
2. There is no standard for how to wire the connectors
3. It is VERY VERY easy to get things wrong and blow up your camera - I got the power and gnd reversed and fried the camera power (yes, I would have thought in a camera that cost thousands of pounds new they would have put in reverse polarity protection, but apparently not!)
4. Even if you get the connectors wired, your mission is doomed, as, unless you also have a matching camera control unit (which also has a big multiway connector), you can't tell the camera to start sending signals down the cable. The CCU talks to the camera and tells it to use the multiway connector. Otherwise most of the signals on the connector are dead. At least that is the conclusion of hours of headscratching on my part.

Oh well. Nice try.

Dave

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