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.
TTA is a simple and stable lossless audio data format for real-time compressing of digital music. Free and fully-functional for any use. It has a very simple structure. The TTA file header contains a unique format identifier, which is followed by meta-data block. Meta-data block contains minimal information which is needed for restoring the original stream (including number of channels, count of bits per sample, sample rate and overall number of samples in file, etc.) and ended by a 32-bit control sum. Following that header, we write one or more audio frames. Each frame is ended by a 32-bit control sum; a decoder may start decoding from any frame in the stream. The compressed samples of channels in a frame are located sequentially, as in a simple PCM data format.