The Preferences window is divided into three sections:

Audio/MP3:
Use soundeffects - You can switch on/off the click-sounds.

Set system volume - Used to force the system output volume to a desired value..

Auto display ID3 tags - During the first seconds of playback of a mp3-song, the ID3-tags (if available) is displayed in the Name-area. By un-checking this option, minor improvement in playback performance can be achieved (if running a slow Mac)

Enable VU meters - With this option checked, VU meters (in the main window, the trackmixer and in the Audio Fullscreen mode) will be active to visually indicate the audio output. You may wish to disable VU-meters if you are running a slow Mac and improvement in playback performance is desired (since VU meters needs to be updated several times per second, it uses some CPU-power).

Disable Mixer engine - With this option checked, all Mixer settings (Overlap, Fade-In and Fade-Out) will be bypassed during playback. This option is useful when running a slow Mac and improvement in playback performance is desired (at the cost of the Mixing features).

Fade-out on Stop/Skip - With this option checked, a short fade-out will take place whenever you stop playback of a song (or when you use Next or Previous to jump to a new song). Note: This option is only available when fade resolution is set to medium or smooth. When fade resolution is set to corse this option is automatically disabled.

Fade resolution - You may set the smoothness of the Fade-In and Fade-Out operations. Fade resolution is described in detail in section 7. The Track Mixer.

Video/Images:
Show movies in fullscreen - MPLAY will playback the movie in fullscreen mode.

Size - With fullscreen playback deselected you may choose a size for the playback window.

Check MPEG-header for size - Quicktime wants to scale MPEG-movies to 320x240. PAL VCD-compliant MPEG-movies are 352x288 and the NTSC equivalent are 352x240. MPLAY will make the necessary corrections for this when this option is checked.

Show images in fullscreen - Images will be displayed in fullscreen mode.

Size - With fullscreen playback deselected you may choose a size for the images.

Show as slideshow - By checking this option, and setting the timeout to a desired value, you may show your images as a rolling slideshow. During the slideshow you may use the spacebar to pause.

Playlist:
Display help-texts - With this option checked, the lower part of MPLAY's window will display information about all the controls.

Prompt to save before quit - MPLAY will ask you if you wish to save the playlist before you quit (if any changes have been made).

Autoplay loaded items - If MPLAY is not playing anything at the moment, loaded/dropped items will begin playing immediately. This applies to playlists, as well as individual files.

Autoload last playlist - MPLAY will remember which playlist you last used, and try to load it at next start-up. If the playlist cannot be found, MPLAY will simply ignore this operation.

Add items alphabetically - Normally, a group of dropped items are added in the order they are given by the Finder. Checking this option will force items to always be added in alphabetical order.

Folder scan-depth - This popup-menu lets you select how deep MPLAY will scan subfolders of folders dropped on MPLAY. Scan-depth is selectable from 1 (no subfolders scanned) to 5.