PVF is a special low-bandwidth ADPCM-based digital audio format for recording and storing human speech. A .pvf file contains digitally recorded speech in the PVF format. Such .pvf files were mainly used with legacy voice modems and software-based answering machines. Often, to be used with a specific modem, a .pvf file would have to be converted into the device-specific RMD format. Currently, PVF audio files can still be played with several major media players as well as converted into other formats (like WAV) with multi-format converter tools.
A file with the CDDA file extension is a CD Digital Audio file that stores audio in the AIFF format. CDDA files are normally seen only when audio files have been ripped from an audio CD that uses the CD Digital Audio specification. This is most often done through the Apple iTunes program with the Audio CD burn option.