To support encoding a control circuit determines a primary prediction mode to employ when encoding a block of video data and then determines a corresponding companion prediction mode to correspond to the primary prediction mode. The control circuit can then generate a mixed prediction for the block of video data by mixing a prediction formed using the primary prediction mode with a prediction formed using the companion prediction mode. By one approach the control circuit determines the corresponding companion prediction mode by accessing a companion prediction mode lookup table. In such a case, if desired, upon generating the mixed prediction for the block of video data the control circuit can also automatically update the companion prediction mode lookup table. By one approach a corresponding decoder infers the employed companion prediction mode (or modes).