VDMX Layers
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Using the Layer Manager
To get things started off, take a look at the Layer Manager palette's window. The Layer Manager is used to create and delete new layers, change their order and composition mode, and "group" layers.
This window is fairly straightforward; to create a new layer, click the "Create Layer" button- to delete a layer, select it in the list and either click the "Delete" button or press the delete key on your keyboard. To group layers, select them in the list and click the "Group Selected" button. The rendering order of layers may be changed simply by clicking and dragging them within the list; layers may also be renamed by double-clicking their names in the list and entering a new name. To the right of the layers' names are pop-up menus for choosing the composition modes of each layer.
The Canvas
In VDMX5 all layers are drawn onto a virtual canvas and then mapped on to the main output window. The canvas resolution determines the dimensions of your working space (in pixels), as well as the resolution at which groups will render (individual layers render at the resolution of whatever's playing back in them). The canvas size can be changed in the Outputs section of the preferences.
From the Output preferences you can also set the Canvas Presentation mode which determines how the canvas should be display in the output window. The three options are:
- Fit - Resizes the canvas such that the entire canvas is visible and the original canvas aspect ratio is preserved. Results in black bars on if the aspect ratio of the canvas differs from the aspect ratio of the output.
- Fill - Resizes the canvas such that the entire output window is covered without changing the aspect ratio. This can result in cropping if the canvas aspect ratio does not match the output.
- Stretch - Maps your canvas to match the dimensions of your output device causing distortions if there is an aspect ratio mismatch.
Rendering Order
Much like Photoshop and many other image-editing applications, layers are the basic building block of VDMX. Without layers, nothing would be visible; movies, pictures, and Quartz Composer documents are displayed on layers. Each layer has a source- the source is the basis of what the layer looks like. The image that comes from the source is then run through the layer's FX chain, which is comprised of a series of video effects that modify the source's image. The resultant image is then composited with other layers- the order of the layers determines the order in which they are composited; layers at the top of the stack are composited atop the layers below them.
While layers render top-down, they may also be grouped. Groups are clumps of layers that are rendered together to produce a single image- the group. The resulting composited image may then have fx applied to it, and is free to be rendered as normal with other layers or groups. In other words, groups let you treat a stack of layers as a single layer- the group may be positioned or affected as a single layer, impacting all of it's component layers. Groups are an important way to organize or split up rendering.
For users familiar with GridPro's processing chain (a basic AB style mixer), this can be recreated with two layers inside a single group. With this setup each layer can have it's own fx chain, and once the layers are composited together fx may be applied to the mixed video stream.
Composition Modes
Each layer and group has a composition mode that determines how the layer is drawn on top of the layer behind it. The default blend-mode is a very efficient OpenGL additive mode, but you can also pick from a list of standard CoreImage composition filters as well as blend modes and transitions made with Quartz Composer.
For connivence the composition mode for a layer can either be changed in a few different places.
- The Layer Source and Composition controls (see below),
- The Layer Manager palette window
- Using a Preview Window plugin
There is one caveat to using the more efficient OpenGL add and over blend modes - if a layer is using an OpenGL blend mode all of the other layers in the same group must also use an OpenGL blend mode. This restriction does not apply to layers that are in different groups or sub-groups. CoreImage and Quartz Composer based composition modes can be used together within a group without any problems.
Layer Windows
Once you've created a layer or two, you'll notice that they appear in layer windows which are used to manage more specific controls for individual layers.
A single layer window can contain multiple tabs which represent different layers, making it easy to adjust the interface of VDMX to fit your screen size - for smaller screens, you may want to have a single tabbed layer window (you will have to switch tabs to access some controls, but you will have more room for plugins and other windows). Each tab across the top of the layer window represents a different layer that you can control.
The order of the tabs corresponds to the rendering order of the layers- top to bottom in the Layer Manager is analogous to left to right in the layer tabs. Clicking on a tab makes it's layer visible in the layer window, allowing you to edit it's various parameters. If you want to make a new window, just "tear off" the layer tab- click and drag on it, and release the mouse once it's outside the tabs; the layer whose tab you dragged out will appear in a new window. To get rid of a layer window, simply click and drag the layer tabs in it to the tabs in another window. Please keep in mind that this can potentially be misleading- while the Layer Manager displays all the layers all the time, the tabs in a Layer Window only display the layers contained in that window. For example, if I have three layers (creatively named 1, 2, and 3- in that order), i can "tear off" layer 2, and put it in it's own window. At this point, I would have two windows- one with layers 1 and 3, and the second with layer 2; even though the tabs for layers 1 and 3 would be adjacent to each other, the rendering order would still be 1-2-3.
Layer windows contain a large variety of controls for the layers they contain; their layer tabs indicate and allow you to adjust rendering order, the interface elements inside the "Source Type & Composition" box allow you to determine what kind of layer it is (movie, quartz composer, or tap- and if it's a tap, what it's source is), the layer's composition mode, and it's opacity. At the bottom of the layer window is another box, with controls for adjusting the layer's size and position. The middle area of the window is for the FX-chain and FX presets. Visual effects can be added to layers using the Video FX palette window.
Layer FX Chains
Immediately below the layer composition controls in a layer window is the layer's FX chain. This is a series of video effects what are applied, one after the other, to the layer's source. The order the effects are placed in can have as much of an impact on the output as the choice of the effects themselves. Each FX in VDMX has its own composition mode, meaning that the effect is applied to the incoming video stream, and the resultant modified image is then composited atop the incoming stream using the chosen composition mode. By default, an fx's composition mode is "OpenGL over".
Video effects are loaded from the Video FX Palette. This window is fairly straightforward- on the left side is a list of FX categories. Click on one of these categories, and the right-hand list will populate with a list of all the fx in that particular category. The fx in this may be created by dragging them into any fx chain, or by right-clicking on them (which opens a contextual menu for deciding the chain the effect will be created in), or by clicking on the triangle to the right of their names, which opens the aforementioned contextual menu.
You can also use the search box in the Video FX Palette to filter the list of FX. In addition to searching by name you can click on the magnify glass icon to reveal a menu that will let you also filter the list by searching the descriptions of the FX (not all FX include descriptions, but most of the standard CoreImage filters do and there is support for the description tag for Quartz Composer FX as well) making it possible to find an FX even if you don't know the name you are looking for.
Once you've added an effect in a layer's FX chain, you're free to change any of its parameters, move it to a different place in the FX chain and or remove it. FX may also be moved from one chain to another simply by clicking on any area of the effect not occupied by other interface elements and dragging it to the desired destination. FX may be collapsed by clicking the disclosure triangles in their upper-left corner, and may be toggled on or off by using the enable/disable immediately below the disclosure triangle. The wet/dry slider fades the effect in and out- if the effect is faded all the way out (or disabled), it's processing is bypassed entirely and your overall FPS out may get a shot in the arm. To delete an effect, click the "x" in it's upper right-hand corner.
FX chain presets
FX chain presets come in two flavors - global and local. A global FX chain can be saved to and loaded on to any layer whereas local FX chains are specific to the layer they were created for.
The global FX chain presets are accessed using the pop-up menu at the top of the FX chain in the layer window. Choosing an item from this menu replaces the fx chain of the visible layer- and *only* the visible layer- with the selected preset. Directly to the right of this menu is an "Options" button which reveals a drop down panel for managing the global FX chains such as adding, removing, renaming and assigning keyboard / MIDI shortcuts.
Below the global FX chains is a bank of 12 local FX chain presets each represented by a button numbered 1 through 12. On the left hand side of the local preset strip is a toggle button that switches whether or not you are Reading (R) or Writing (W) to the buttons when you click on them. When the read/write toggle is set to R clicking on (or triggering via a shortcut) one of the numbered buttons will load the stored FX chain onto the layer. When in the W position this same action will write the current FX chain into that button. Buttons that already have stored FX chains have a red dash along the top and the most recently triggered button will be in the on state. Local FX chain presets and their assigned shortcuts stay with the layer they were created with making it possible to change FX chains on a specific layer even when the layer isn't currently visible in a layer window.
Layer Source Type & Composition
Immediately below the tabs running across the top of layer windows, you'll notice a collapsible box labelled "Source Type & Composition". This box, as you might expect, holds a number of interface items which allow you to adjust what kind of layer it is (movie, quartz composer patch, or tap), the layer's opacity, and rendering mode. The box is collapsible because many of the controls inside it are duplicated in other parts of the application- if you like having this particular set of controls visible, go for it. Otherwise, don't worry- you'll see these controls in other windows (such as preview windows and the layer manager). With the exception of the "Source Res?" toggle, the contents should be fairly straightforward. The two most commonly used controls are the layer's composition mode, which determines how it's blended with the layers below it, and it's opacity slider- which is coupled for convenience with a show/hide toggle. The "Use Source Res" toggle determines whether each layer or group is rendered at it's native resolution, or at the resolution of the main output window- this can potentially have a huge impact on performance. By default, layers and groups default to source-res processing- under most circumstances, this is typically more efficient; all this changes if the footage you're working with is larger than your output window (a situation which makes sense to avoid, as it wastes your computer's resources).
Layer Size & Position
Similar to the collapsible box containing the visible layer's source type and composition controls, there's another box at the bottom of the layer window labelled "Layer Size & Position". This box houses a set of controls used to adjust, not surprisingly, how big and where the layer is positioned.
The layer position controls have three different modes (the default is "offscreen"). This setting determine the range for the x and y position sliders for the layer.
- in "offscreen", maxing out the x/y sliders will position the layer totally outside its group/canvas
- in "onscreen", maxing out the x/y sliders will position the layer as far as possible in one direction while keeping it totally visible in the group/canvas
- in "center", maxing out the x/y sliders will position the layer halfway outside its group/canvas
Each layer also has three sizing modes which work similarly to the canvas presentation modes listed above - fit, fill, and stretch. While the canvas presentation mode determines how the canvas appears in your output device, the layer sizing modes determine how the layer appears in its group (or in the canvas, if the layer isn't part of a group).
Layer Source (Movie, QTZ, Text, Image, Web) Controls
The Layer Controls plugin is used to access the controls for any media that is being played back on a layer, such as the transport (time, speed, volume, scratch) controls for a movie, or the inputs for a Quartz Composer document. The controls for a layer exist even when not being viewed by a plugin, making it possible to use a single Layer Controls to set up and manage multiple layers at a time.
All layers have sources- the source is the basic video source that every layer starts out with. Currently, there are seven basic layer source types: Quicktime movies, Quartz Composer documents, text files, still images, live inputs, webpages, and video taps. A layer's source type may be explicitly set in the "Source Type & Composition" box, or by triggering cells in a media bin.