1. Overview

In DC Media, layers are by default rectangular and are displayed in an order ranging from the bottom-most layer to the topmost layer and this allows for content overlapping.  Using masking it is possible to create non-rectangular or framed layers using mask images, thereby revealing content displayed in underlying layers.

2. Masking for logos

In the following example a full screen layer is created and populated with a list of video files. A second much smaller layer is created above the video layer and the objective is to use this smaller layer to display a logo over the video:
If a rectangular logo is placed in the top most layer in the designer:

When the playlist is played out, the content looks as follows:

As you can see with the logo above, the logo itself is an ellipse however without masking; the background of the logo is displayed over the video image.  At this point, we want to introduce a mask image.  A mask image is an image that has an area filled with solid black (RGB 0,0,0) whereby the black area is intended to be transparent. For example, the mask for the logo used above would be:

DC Media will use the black portions of the image to create transparent areas within the layer. The result of adding this to the above playlist would be:

To add a mask using DC Media:
  1. Select the layer that you would like to mask and click on the properties icon or double click on the layer itself.
  2. In the Layer Properties window, select Custom Mask File as the layer shape. Enter the file path of the mask bitmap file and click OK.
  3. Preview the playlist to see the masked effect (larger mask files will take some time to process initially; this will result in a black screen for a few seconds or minutes depending on the complexity and size of the mask image. The mask data will then be cached).
  4. To create a mask file, using Photoshop, the GIMP or Paint. Use RGB 0,0,0 to fill any areas that you want to have appear as transparent.

Important When you create your mask image, be sure to save the file as a 24 bit color BMP or 32 bit color BMP. If you save your mask file as a JPEG, the JPEG compression will create black pixels that are not RB(0,0,0) and the result will be a speckled mask.