The ornamental design for a portion of a mediaplayer, as shown and described.
FIG. 1 is a front isometric view of a portion of a media player showing our new design; and,
FIG. 2 is a front elevational view thereof.
The broken line showing of various regions in the Figures, including the unshaded areas therein, is for illustrative purposes only and forms no part of the claimed design.
The broken lines, which define the bounds of the claimed design, form no part thereof.