1. Preparation

Fri - March 3, 2006

The VLOBLIVE toolbox - what to pack for a video gig?

What items would I always take in my toolbox to a VLOBLIVE gig? Read on to find out.

Based on my experience, here is a bunch of stuff that I would always try to pack in my toolbox when doing a VLOBLIVE gig:
In no particular order...

• white pvc tape - to mark inputs on mixer and monitors etc.

• black pvc tape - to tape cables together.

• permanent marker - sharpie or similar

• contrast setup powerpoint file on USB memory flashdrive thingy.

• Allen keys - useful for projector brackets etc.

• A selection of video plug adapters including at LEAST an Svideo to BNC jumps, BNC-phono adapters, VGA Male-to-female adapters, SVideo joiners, LOADS of BNC joiners, phono joiners etc.

• spare laptop - yes really! doesn't have to be up to much but must be able to load and display a powerpoint presentation.

• test tapes - just SOMETHING recorded onto whatever tape format you are using for playback.

• test DVD - can be anything, but one with test charts etc. would be ideal.

• blank tapes to record the show.

• cableties - indispensible. Big and wee ones please.

• adjustable spanner

• soldering iron

• solder

• wire cutters

• TV remote (if you are using TVs as monitors)

• BNC crimper - optional, but very nice to have.

• Spare BNC crimp connectors

• spare headphones - to let you monitor recording audio etc.

• Notebook and pen - to write lists of things to do

• 30m tape measure - to measure screen drops, cable lengths etc.

• head-mounted torch - for peering in the back of dark rack cases.

• Every known type of battery - or at LEAST lots of AAA, AA and PP3s

• USB cable - you never know!

• Gaffer tape (of course)

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Sun - August 21, 2005

Making a 'play-then-pause' DVD in DVD Studio Pro

Here's a quick 'how-to' provided by Buzz Miller (who got it from Nick Fox-Gieg ) on how to design a DVD in Apple's DVD Studio Pro app that will play one clip then pause on black, then play the next clip and pause etc. If you're doing a VLOBLIVE event short-handed and need to know that there is NO WAY to play the wrong thing on the DVD, this is a good approach.
Thanks Buzz.

Back in this item I suggested making a custom menu specially designed for live play-in of DVD clips.
Buzz goes one better by doing away with the menu altogether and just chaining the clips together. His 'secret sauce' is to add a 'wait' in between each clip so you have to do something (press play) to get the DVD player to play the next clip.
The big advantage of this is that the DVD menu will NEVER appear by accident on the screens.
The only disadvantage is that you have to fix the sequence, and there's no real clue what's about to play other than the track no.

Here's how Buzz does it:

"In the Assets tab (upper left) I import the clips (including one that fades to black, and I usually include a short 3 sec black clip that I start each disk with).
Then drag your clips (in the order you wanna use 'em) from the Asset window to the Track timeline (bottom).
In the Outline tab (upper left), click on the UNTITLED_DISC icon to activate the Disc window (lower right)
In this Disc window:
- name the disc.
- change First Play from Menu 1 (I don't use menus) to Track 1 > Chapter 1 (the short 3 sec black clip).
Back in the Outline tab (upper left) click on Track 1 to activate the Track window (it was just the Disc window, lower right).
In this Track window:
- Create chapter markers in the Timeline window at the start of each new clip, by clicking in the space above the time "ruler." It can be tricky to navigate and be precise, so I use the keyboard shortcuts to zoom (Apple + & Apple -) and the up and down arrow keys to go to the breaks between clips.

- set End Jump to "Tracks and Stories" > Track 1 > Chapter 2

- back in the Track window, under Playback Options, the Wait setting is the key to letting your disc park on the last frame of the given Track or Chapter. Set it to Infinite and it will keep playing the last frame (often black if you made your clip fade to black in FCP). Or set it to x seconds if you want it to pause on the last frame for a specified amount of time.
When it comes out of Wait, it will do what you specified in the End Jump setting above."

There you go. I haven't tried this myself, but it is a good illustration of how to use the power of a tool like DVDSP to make your VLOBLIVE life much easier.

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formatting song words for use with IMAG

If you know in advance that you are planning to overlay words on IMAG live video, then you can help yourself out by formatting the words in a sensible way. ...

In most situations it is not necessary to fill the entire screen with words, when projecting song words.
Most people do, but it is just lazyness, and lack of thought. To have live video running behind a full screen of words is very distracting in almost every case. If, however you put the words onto more pages so each page has less words then you have some scope to move them around a bit and let the IMAG and the words complement each other very effectively.

This is best illustrated with some examples:

Here is an example of what NOT to do, if possible:

Putting Paul Oakley right behind the words doesn't do him any favours and makes it very distracting.

Or this one:

It's a very nice guitar, but is totally hidden, and any movement by the guitarist will make it hard to read the words.

So instead, how about:

Here the words and the singer have their own space on the screen
(Strictly speaking this is poor framing for the video, as the singer has no 'looking space', but it is acceptable in this context)

Or this is OK too:

Words on top, video on bottom - that's fine.

Or, if you want to get fancy:

You can find little gaps in the words to fit people into.

Or best of all, make sure your words leave plenty of space in the first place:

Your camera operators will need to be awake if you are trying this, and may have to gently adjust their shots once onscreen.
It also helps if the vision mixer can see a preview of the next screen of words, so they can tell the camops how to line up their shots.

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Tips for preparing video for live playback

A lot of the info on this site relates to live camera work, but playing back video clips is a very common requirement for VLOBLIVE events, and there are quite a few things you can do to make this work better...

Here are some basic tips to get the best out of any playback clips:

- review any clips that you are not preparing yourself BEFORE the event, so there is time to change them. Don't assume that everything is fine.

- Use the best playback format you can. In order of quality for normal 'prosumer' formats this would be Digital Video tape (DVCAM, miniDV, DVCPro etc), then DVD (or MPEG2 video on PC/Mac), then S-VHS, then normal VHS, then SVCD (or MPEG1 playback on PC/Mac).

- if it is possible put all the clips on the same tape or DVD and put them in the correct order. There is nothing worse than hunting around for a mislaid tape, or rewinding through a tape to find the right place while under pressure. Having one tape with only the bits you need, in the right order is a big help.

- ALWAYS make backup media

- On tapes always enable the record protect tab

- put black video before and after for 10 s minimum

- make life easy for the PA guy and add audio fades at the start and end if necessary

- watch the audio levels if going to analogue tape - they should be peaking at -6dBFS digital

- keep DVD compression low to avoid artefacts

- add a countdown to tape. You know the 8..7..6..5..4.. thing that you see at the start of movie clips. This may sound naff, but for cueing up tape is a lot easier when you have a proper countdown that drops out at 2 and let's you accurately cue on black. You can find an example one here.

- adjust blacklevel and midtones on your video clips to give a good histogram of exposure.

- add a tech title before the countdown, so whoever is playing it in knows they are playing in the right clip. Always say what the duration is, what the audio is, and ideally what the first frame and the last frame are, so folk know what to expect.

- If possible try it out all clips on the projector you will end up using. this will ensure that you can get the brightness levels right. if you can't do this, then play them back on a TV or monitor with the brightness control turned up a bit and the contrast control turned down a bit (to simulate a lower contrast ratio on the projector)

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Mixed VGA and Video - what are the options?

Most VLOBLIVE events require both video sources - VCRs DVDs cameras etc. and also PC graphics sources. Somehow both of these types of signals have to end up at the projector.
Here's a quick lowdown of the main ways to do it and why you might choose each one...

There are three main approaches to setting up a mixed VGA/Video system, and each has its advantages and disadvantages.
I will try here to describe them and say when you might use one or the other.

First let's explain what I mean by VGA and Video, as the terms are often interchanged.

VGA means analog or digital progressive scan PC graphics format (regardless of resolution) using separate Red, green, and blue signals. This is sometimes known as RGBHV. This is normally what goes between your PC or Mac and your monitor and is most familiar as the 15 pin D-type connector.

Video means any form of interlaced video - composite, svideo, component etc, but basically it is video signals at standard TV resolutions (Let's ignore progressive scan HD video for now).

The main point to note is that they are not compatible. They run at different frequencies, they have different numbers of lines, they 'draw' the image in different ways, etc. etc.

So if you are going to start with both VGA and video signals, and end up at a projector, you have three main options.

1. Keep them separate all the way to the projector.

In this option, the video is switched or mixed separately from the VGA and both signals arrive at the respective projector inputs. Any switching between them is done at the projector, or via the remote control, or via a serial port etc.

In reality of course, the video has to be scan-doubled up to the native resolution of the projector LCD or DLP panels so the conversion is 'invisible' as far as the setup is concerned.

Advantages:
+ No special converter boxes required
+ easy to configure
+ full VGA quality maintained for graphics

Disadvantages:
- twice as much cable required (VGA and Video)
- video scaling is dependent on internal scaler in projector - may not be very good!
- often slow to switch inputs on the projector (has to re-sync). Can be several seconds!
- can't fade between graphics and video

When to use:
When you are MOSTLY showing graphics and only the occasional video
When you only have one video source

2. Video all the way

This approach stems from a 'broadcast' model where everything gets turned into video, and then mixed, tweaked, and displayed as video.

This then requires that the PC graphics get converted from their native format (SVGA, XGA etc) into standard video resolution, and also the timing is changed to suit the interlaced TV format.
To do this you typically use a box called a scan converter, or some graphics cards may have this function built in and provide a TV out port.

Once the VGA is converted to video, you can mix, switch and route it just like normal video.

Once the video signal gets to the projector it is converted BACK into VGA to match the native resolution of the projector, and this requires another conversion step. Inevitably the quality suffers a bit at this stage, and there may be a delay introduced of a few frames (not a big deal for playback, but pretty noticable for live camera feeds). How much the quality suffers depends on how good the converter chips in the projector are.

You can compare this, if you connect a PC with a TV out graphics card AND a normal VGA output to the same projector. You can then switch between them at the projector, while displaying the same signal, and you will notice a significant drop in sharpness and quality for the video signal.

Advantages:
+ common cabling throughout
+ only one cable needed to projector (cheaper than VGA cable)
+ can use standard video mixers, switchers etc. including ex-broadcast gear cheap from ebay
+ easy to do graphics overlay (words over pictures) using Keying on mixer

Disadvantages:
- loose quality on the PC graphics - how much depends on scan converter quality
- rely on internal video converter chips in projector
- good quality scan converters are expensive (cheap ones are rubbish)

When to use:
If you are doing mainly video (IMAG or playback) and only occasional PC graphics, or if your PC graphics are mainly song words overlayed on live video.

3. VGA all the way

This approach stems from the 'presentation graphics' model where everything is cabled as VGA, and interlaced video is a weird language that needs to be translated as soon as possible.

The most common way to achieve this approach is to use what is often called a 'seamless switcher' or a 'presentation switcher' which accepts both video and VGA inputs and scales them all to match the native resolution of the LCD projector.
Ultimately this keeps the best possible quality on the VGA signal, while maximising the conversion quality of the video. The conversion chips in a seamless switcher are significantly more sophisticated than those in a projector, so the results are generally a lot better. Having said this, the cost of even the cheapest seamless switcher is about the same as most sane people would pay for the whole video projector, so it is no real surprise.

Advantages:
+ best possible quality for all inputs
+ no conversion required at projector
+ only one cable needed to projector (albeit a more expensive one)

Disadvantages:
- VERY expensive for seamless switcher (but there IS a cheaper way using a software solution)
- cabling is all more expensive
- even more delay introduced for live inputs (cameras)

When to use:
If you need the best possible quality of graphics AND you regularly use video, and you have plenty of money.

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A note on S-Video connections

S-Video is a great thing for vloblive technicians – it gives you a lot of the benefit of component video in terms of quality, without increasing the cable count too much. The big downer of S-Video is that, invariably it requires connection with those horrible little miniDIN plugs. Not only are they hard to orient in a hurry, but the pins bend easily and they have no mechanical locking mechanism. Here's one way around it...

In the broadcast market, the normal practice is to use component analog video with separate cables for the three primary (RGB) or complimentary (YUV) colour components. Many now have abandoned analog completely and go for digital SDI. Meanwhile In the industrial (better than prosumer but not broadcast) market they have long since abandoned miniDINs in favour of either a 7-pin connector with a locking ring (JVC, Panasonic etc) or two BNC sockets – one for Y (luminance = brightness) and one for C (chrominance = colour).

There is a way to get the benefit of S-Video with longer cable runs without the pain of miniDINs
Use a miniDIN to BNC adapter or ‘jump’ as they are called. This is a miniDIN connector with two short cables coming out, going to inline BNC sockets. This lets you split out the Y and C onto high quality coax video cable. They are especially useful for long cable runs, but can also be used in any situation where you have to cable S-Video with the maximum quality of interconnect. You can get some mechanical stability by cable-tieing the the BNC connectors to something solid,, or better still use a back to back BNC patch panel in your equipment rack to join to longer BNCs.
One final note - I don't recommend that you try to make them yourself - it IS possible, and I have done it, but you will get much better results just buying one. I think that markertek in the US and VDC in the UK do them.

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What is the best kind of connector to use for video interconnect?

If you are using a whole mixture of equipment, chances are you have a mixture of BNC, phono and maybe even other connector types for your video interconnect. Which is best and why?...

Answer:
The BNC connector with its rigid construction, correct impedance and mechanical locking ring is by far the best type of connector to use for all types of video interconnect. The problem of course is that a lot of prosumer gear uses the good old phono connectors, because they are much cheaper to make. This means that inevitably you will have to interchange between different connectors in your setup.

In this context the best type of connector to use is the one that gives the best quality of connection (both electrically and mechanically) while minimizing the amount of cables and connectors needed to make the link.
There is no point in using lots of extra adapters and cables JUST to be able to use BNCs, if they don’t give you any benefit. If a cable is static for most of its life, or lives in the same place, or has no strain applied, or is only connected or disconnected infrequently (say, inside an equipment rack) then a phono connection may be fine.
If, however you are attaching a long cable that may be pulled, or jarred, or that is disconnected and reconnected very often (e.g. on a camera or projector)then you should be looking to convert to BNC as quickly as possible.

This is one advantage of cabling up your equipment into a rack or box. It allows you to do all you connector adapting in a nice fixed, secure way, so no problems later. You can use short ‘jumps’ to go from one type to the other.

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Projector screen size - bigger is better, right?

Given the option you always want the BIGGEST screen you can find for projecting onto.... or do you?...

Is there such a thing as too big a projection screen?
Surely if you have the budget and the space onstage, a huge screen gives the maximum visual impact.

Well, no, not really. Here's why not:

As you increase screen area, your projector has to spread its limited lumens over a larger area, and the resulting image gets dimmer and dimmer. Assuming that you actually want the audience to see what you are projecting, it's worth sticking to a reasonable size for your given projector brightness.

Some rules of thumb might be:

less than 1500 lumens, front project - stick to around 8 ft x 6ft
less than 3000 lumens, front project - stick to around 10ft x 7.5 ft
more than 5000 lumens - do what you like, as you are obviously NOT a VLOBLIVE techie, and have far too much budget to play with.

The figures for back project in a theatre or other controlled lighting environment would be a bit better.
I have done 10 x 7.5 backproject with a 1500 lumens projector and got off with it, but only in a virtual blackout.

Consider adding MORE screens rather than BIGGER screens, if you really need the coverage.

In addition there is an aesthetic issue here too. Too big a screen can be very distracting for the audience, as it starts dominating their field of view, and it stops enhancing the live action and becomes the action itself. Your audience may as well be watching TV!!

Remember too that screen size has to be matched to the venue. A 10 x 7.5 screen may seen HUGE in a small hall, but in a 3000 seat auditorium it isn't that big.

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