The last form of Keying we wanted to highlight is Linear or alpha keying. Linear or Alpha keying is the evolution of the Luminance key and Pattern keying (read HERE). Linear keying becomes a basis for where we can build almost all advanced keying. It typically requires special hardware and software but gets you great results.
Linear keying is made from two separate signals. The first signal is called the Cut Signal. The Cut Signal is a luma-based signal of white, black, and grayscale that tells the switcher what is opaque (black) and where to put a GFX signal (white). The second signal is the Fill Signal or the actual GFX or colors. (Pictured above) The switcher uses the Cut Signal as the pattern shape, which allows the benefits of a luma key while eliminating the con of not being able to have things like a black outline. This is because the switcher is using one signal to say where things are opaque and another for what the actual content will be.
Luminance and Pattern Keys
Keying is a powerful and essential feature on your video switchers. It's important to know the basics behind keying so you can really understand what is happening on your switcher when you use these features. We've talked about Chroma Keys, HERE, so now we want to highlight another similar switcher key: Luminance Keys.
If you, like many over this last year, are new to pro video switchers, their terminology, and features you may be wondering about ME’s. ME’s are where the magic happens in video switchers and are comprised of controls each with a row of buttons for Preview and Program. Program is the video source you are sending out and Preview refers to the video source you are intending to transition into next.
Let’s start by talking about what ME stands for. An ME stands for Mix Effects Bus. To understand what this is we will break down each word. First, we can start with M or Mix. Mixing is the combination of two or more elements. At its most basic function, a video switcher does just this by mixing different sources such as multiple cameras or a GFX source.
Compression on a vocal
Last week we had an introduction to audio compression. Today let's take a look at why you might add compression to vocals!
For speaking vocals, I rarely use any compression. The main reason for this is that you will lose some of the dynamics and if you are not careful it can make them sound very unnatural. On the other hand, for singing vocals, I love being able to use compression! If I have a console that will allow me to, I like to do two stages of compression. For the first stage, I like to use compression as more of a soft limiter (somewhere in the 7:1-10:1 ratio) with a pretty high threshold. Most of the purpose of that compressor is to trim the loudest part of the vocal. Then I use a second compressor to “squish” the rest of the vocal a little bit (Ratio 2:1-3:1, a medium threshold (3-6db) ) and to make-up a little bit of gain to keep my gain structure correct. My main goal, as with any compression is to try and get the vocal more consistently coming out of a PA or on a stream. But, this doesn’t mean that it’s always the right choice! Sometimes adding a compressor to a singing vocal or adding too much compression can make a vocal feel un-natural or thin. So, use with caution and always mix with your ears and not your eyes!
Trevor- Lambda Audio Visual Sound Engineer
What is it? How and When Do You Use it?
Welcome to Trevor’s Audio Master class. I will be your guide to the wonderful world of Compression. The definition of a compressor is, “An audio signal processing operation that reduces the volume of loud sounds or amplifies quiet sounds, thus reducing or compressing an audio signal's dynamic range.” I’m sure that cleared up any confusion on compressors. Any questions??
Ok, but seriously. These are questions that we often get when we are doing sound training. What is a compressor? How do you use it? When should you use it?
Easter is just around the corner and it’s a good time to talk about making AV Goals. Audio Visual systems are an investment for your business, but sometimes it can be hard to make the final decision on when or how to invest in new equipment. How do you know which areas to invest in your AV system and what things can wait? This is where a little careful planning can take you a long way.
Getting a good tight follow may take some time and practice before you feel experienced enough to capture every movement, but having good positioning will help your shot look more professional no matter what you are doing. A clean, tight follow will always elevate the level of production you are hoping to achieve.
We realize that sometimes you just want to make a simple cable swap or another easy change on your own. At Lambda our main mission has always been to empower people to know their equipment and be able to get the most out of it. This is why the team at Lambda has been working hard to create resources for you to use this last year, including instructional graphics for camera operators.
We want to continue to provide practical tips for you to use so your company and staff can continue to grow. So, be sure to send us any questions or topics you’d like to see addressed here or on social media. Also, be sure to keep reading future issues as we have a lot of DIY tips coming up and if you haven’t heard about our jobsite guide, we’d love to get one into your hands! More to come!
A while back we talked about the “Lambda process” for turning your dreams of new audio, video, or lighting system into a reality. A big part of that process is all about the gear testing that happens in our shop before the equipment ever gets to your location. After the gear has been ordered and arrives, we set up all the equipment and each component in our shop just as it will be for the install. This ensures that when we arrive for the install, there aren’t any surprises and there won’t be “that one missing part.” Along with that, we have an assurance that each piece of the gear we install will work for you leaving no questions of whether your new parts are faulty. This detailed process not only assures that each piece is built properly, but that they all work together flawlessly.
Or Text 22828
All of the Lambda Staff contribute to the Blog. If you have any questions about the info we provide, please don't hesitate to ask!
Check out our resources page for FREE checklists and tools we mention in articles! We are here to help you improve and maintain your Audio Visual Systems!