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Conduit Live: Getting Started with Stage Tools

From ConduitWiki

Conduit Live is a standalone Mac application that's included in the Conduit Suite bundle. On its own, Conduit Live already does quite a lot: video capture, live color keying, offline compositing... To unlock the power of Conduit Live, it can be further extended with add-ons that provide new tools and user interfaces for specific use cases.

Stage Tools is an add-on that turns Conduit Live into a powerful live system. With Stage Tools, you can design and execute video shows, theatrical performances and many other kinds of installations that deal with video in some way.

This document covers the essential principles of Conduit Live and Stage Tools. If you're new to Conduit Live and would like to learn the basics of how to build a show, this text is for you.

If you need a more specific overview of all the features and capabilities included in Stage Tools, please see CL2 Stage Tools.

Contents

How Conduit Live works

If you're familiar with typical video editing applications, you'll find that Conduit Live works very differently than what you're used to. This is because the fundamental metaphor is different.

Video editing software uses a film-strip metaphor: your video content is represented as a timeline with frames flowing from left to right. This metaphor originally comes from physical film edit desks. It's very suitable for editing, but doesn't work so well for representing live situations, where the duration of your content is not known beforehand.

Conduit Live uses a control room metaphor. There is a room full of devices, and you decide how they are connected to each other. Some of the devices produce images (like a camera or DVD player) and some produce control signals (like a lighting control desk). Some devices process video images, like a video mixer. Finally, some devices output video onto a display or projector, or record them to disk.

Stage Tools includes a robot that knows its way around the control room. It can do practically anything that a human operator could do: move sliders on a controller, load video clips into a player, change video mixer settings after a given delay, and so on. But the robot, like others of its kin, is limited by its inability to think for itself. It only does what its programming tells it to do.


Building a show in Conduit Live is a two-stage process. First you design the "control room" that you need. You'll need to ask questions such as: How many images do we need to bring in? How many screens or displays do we need to output onto? What kind of effects will we need?

Next, you program the "robot" to operate the control room. The robot's programming is a list of events or cues within the show. Unless you're working alone, these cues are often determined by the show's script and direction. At this stage, you'll be answering questions like: When do we need to show a camera image? When should another image fade in? When should an effect change to another? Etc.

When the show is built this way, it's very easy to run it: just go through the events at the right cues. To minimize guesswork within a hectic show, description texts can be attached to events. A simple information display makes it obvious what should happen next.

To provide live controls for effects, just attach a MIDI controller, and you'll have direct physical sliders with motorized feedback from Conduit Live. With these tools, anyone will be able to operate the show on your behalf.

The control room

Conduit Live was described above as having a "control room" metaphor. This control room is in the Project window:

conduitst_project_20100909.png

On the right-hand side of the Project window, we see boxes interconnected by cyan and purple lines. These represent the different "devices" within the control room. The connections between the devices are like electric wires that transmit signals from one device to another. As in the real world, some of these wires carry video and others carry control signals. The color of the wire indicates the type of content. (For more details, see CL2 Node Widgets).

The "devices" are called node widgets. Connections between them are read from left to right.

In the above screenshot, the right-most device is Multi-Display. This is the standard video output device. It can display multiple images, which is why it has four video inputs. You can easily direct the images onto different projection screens using a Matrox graphics expansion module (GXM). (More info) Using a Matrox GXM, a single Mac laptop can output onto three separate projectors, and a Mac Pro can be configured to output images on up to 9 projectors.

Moving on in the screenshot, on the left we have two devices labelled Image/Movie Source. These are video players. You can load either movie clips or still images into them. Each player has its own playback controls. The button with the "eye" icon opens a preview window, which also offers scopes for analyzing the video content.

Between the video sources and the Multi-Display, there is a big node widget labelled Conduit Effect. This is like a video mixer. It can take up to eight individual video connections, and also a set of control signals. The control signals can be sliders, color pickers, or some other kind of values within your project. What differentiates the Conduit Effect from a typical video mixer is that it's fully programmable. You can completely "re-wire" the mixer's internals to create layer effects, color corrections, image warps, blurs... This is accomplished using the Conduit Editor, a powerful visual effects creation view. (More info: CL2 Conduit Editor).

Finally, the above screenshot has two node widgets labelled Slider Bank and Color Pickers. These devices output control signals. To modify the values with on-screen controls, click "Show Window". Sliders are important because they are the easiest way to create animation within live situations. The idea is to instruct the Stage Tools "robot" to manipulate the slider, for example: "Move Slider 3 smoothly to a value of 0.5 during the next two seconds."

It's important to note that the sliders don't have any meaning on their own. The Slider Bank node widget needs to be connected to something that responds to the values in some way. The Multi-Display output can use the values to composite images: just connect Slider Bank to Multi-Display's last input. For more complex layering and effects, you can use the Conduit Effect. (Inside the Conduit Effect, the slider values are represented using Slider nodes.)

You can get physical control and feedback for sliders using a MIDI controller. For easy setup, we recommend a Behringer BCF2000 controller, which is automatically recognized by Conduit Live. (You can also use any other MIDI controller by configuring the sliders in Conduit Live's Sliders window.) Conduit Live supports MIDI feedback, so motorized faders (available on the Behringer BCF2000 unit and many other pro controllers) will be automatically synchronized to the sliders you see on-screen.

The cue robot

To build a show that runs on its own, we need a way to automate tasks in the Conduit Live control room. This "robot" can be found in a window simply labelled Stage Tools. To open it, choose "Show Stage Tools Events Editor" from the Tools menu:

conduitst_events_20100909.png

This is the interface for building a list of events: things that needs to happen on specific cues within the show. We can also call it the cue list.

To create a new event, press "Add". This opens the Edit Event window:

conduitst_editevent_20100909.png

Each cue actually consists of one or more events. In the bottom left-hand corner of the above screenshot, you can see the different types of events. To load a video effect, use Conduit event. To manipulate slider values, use Slider event. To load video clips and control playback, there's Image/movie event and Play/pause event... There's also JavaScript event, which allows you to enter programming commands that can make the cue do almost anything within the project.

Cues don't have to contain all the necessary commands in themselves: you can create cues that are based on another cue. This "master" cue will be triggered first. To create this type of cue, just select a cue in the Stage Tools window, then select the master from the Based on menu in the top right-hand corner of the window.

These master cues are particularly useful when you need to share an effect between multiple cues. For example, you might have one effect setup for basic layering, and another with a color correction setup to make live video stand out. You could place these effect setups in their own cues, and have all the actual cues be based on the master cues. This way, the effects remain editable in one place: when you update the effect, all of the cues that refer to it will follow.

During the show

When the show is running, Stage Tools provides a concise interface that shows only the relevant information about cues and timing. This Info window is opened by choosing "Show Stage Tools Info Window" from the Tools menu:

conduitst_stageinfo_eng_20100909.png

At the top is a running clock that shows the time elapsed since the start of the show and the previous cue. If you don't need this information, just toggle "Show clock".

At the bottom of the window, the "Now" and "Next" columns show the last triggered cue and the following one.

The text in yellow is the description that was entered in the Stage Tools window. It's a good idea to use this field to contain simple, unambiguous information about when this cue needs to be triggered, and what other things may need to be taken into account. This way, the person running the show only needs to watch the Info window.

There are a few ways to trigger cues. In the Stage Tools window, you can double-click on the list. (Single-clicking selects the cue for editing.)

When the show is running, you can press the Esc key anywhere in the application to trigger the next cue in the list. Alternatively, you can press Return: this is the "other Enter key" found on many Mac keyboards. (On MacBooks, it's usually to the left of the arrow keys; on separate Apple keyboards, it's together with the numeric keypad.) Some newer Mac computers don't have the Return key at all.

There's more

Conduit Live with Stage Tools has many other tools that don't fit within the constraints of this article. Here are a few that may be of interest:

  • DMX Source - use a lighting control desk to drive video in Conduit Live
  • Perspective Warp - used to correct e.g. distortions from a projector that's placed at an angle
  • Live Titles - a text tool that's particularly useful for live subtitles: it has a separate "cue list" for its titles, and supports complex styling with colors, drop shadows, etc.
  • Playback Control - very useful for controlling video playback based on slider values or other control signals, for example: "when Slider 2 is lifted more than 5%, rewind the video clip and start playing"

The Conduit Effect node widget is a large topic on its own; a complete visual effects system that you can also use in Final Cut or After Effects. You can read more about it in CL2 Conduit Editor.

Finally, it's worth mentioning that although Conduit Live is specially designed for live use, you can also use it as a standalone video compositing application. There is a separate Timeline mode for this kind of work. In Timeline mode, Conduit Live behaves more like a video editing application, and you can export your work. (More info on Timeline vs. Free Run mode)


Thanks for reading this far! If you have any questions, please don't hesitate to get in touch.

This document was written by Pauli Ojala. His email address is (first name) @ lacquer.fi.