The default video system checked is NTSC. In the Rendering page of the Preference Settings dialog (File/Preferences), you can change the video checking to PAL.

The sample slot does not automatically update when you change the video system preference. Turn video checking off and back on to see the change.

You can also check for legal video colors when you render a scene.

Note: The Rendering page also shows options for choosing alternate ways to display illegal pixels - these apply to renderings only, not to the sample slots in the Material Editor.

To assign a material a material effects channel ID:

Choose a channel number from the Material Effects Channel flyout.

The channel number can be from 1 to 15. Zero (0) means that no ID is assigned to the material's effects channel.

If you assign the same effects channel number to more than one material, all materials with that number are used in Filter or Layer masking, or receive special post-processing.

Note: Giving a material a non-zero effects channel number tells the Renderer to generate an RLA channel containing such numbers. This information is saved only if you save the rendered scene to a .rla file. However, the effects channel data is available to Video Post when it post-processes your rendered scene.

To change the preview shape:

Make sure the sample slot of the material you want to view is active.
Use the Sample Type flyout to choose the shape you want to view.

The new shape appears in the sample slot, with the material mapped to it.

The flyout gives you three options: sphere (the default), cylinder, or box.