The structure of MPDP files is typical of audio files. MPDP is the file extension used by MixPad. It is an audio mixing program. MPDP files store audio projects made in MixPad. The files do not contain actual audio data. They contain information on: number of tracks, audio files used, and other data. MixPad is used to produce recordings. The recordings use multiple sound sources. The sources are mixed appropriately.
Only MixPad can process data from MPDP files. Use MixPad to export the project file. Export to supported formats like MP3, FLAC, WAV, AAC or M4A.
You may need to update MixPad. Only the latest MixPad version supports the current MPDP format. You should check the MPDP file for viruses. Scan it with antivirus software like Norton or Nod32.