PWADs can include music lumps for custom music when played. Originally, these lumps were encoded in the MUS format. WAD editors need to convert between that and a format used by music authoring tools, such as MIDI. Since v1.5, Doom has been able to read standard format MIDI files for music, as long as they are no larger than 64kb. The Windows 95 version of Doom, Doom95, however does not have the ability to play MIDI files. Many modern ports will accept MIDI lumps without any limitation.