| VQF is one of the "alternative" audio compression formats back in 1990s that was aimed to take over MP3 by providing better audio quality than MP3 with lower bitrate. Failed miserabely due various reasons, most notably because of restrictive licensing. Nowadays the only serious alternatives to MP3 are probably Ogg Vorbis and Microsoft's WMA.
TwinVQ is proprietary audio compression format developed by Nippon Telegraph and Telephone Corporation (NTT) and marketed by Yamaha under the name SoundVQ. Its file extension is .vqf.
TwinVQ supports constant bitrate encoding at 80, 96, 112, 128, 160 and 192 kbit/s. It was claimed that TwinVQ files are about 30 to 35% smaller than MP3 files of adequate quality. For example, a 96 kbit/s TwinVQ file has roughly the same quality as a 128 kbit/s MP3 file. The higher quality is achieved at the cost of higher processor usage.
Yamaha marketed TwinVQ as an alternative to MP3, but the format never became very popular. This could be attributed to the proprietary nature of the format -- third party software was scarce and there was no hardware support. Also the encoding was extremely slow and there was not much music available in TwinVQ format. As other MP3 alternatives emerged, TwinVQ quickly became obsolete.
Some software still supports TwinVQ. NTT still maintains a website which offers its own player and encoder for download, Nero Burning ROM is able to encode to TwinVQ, and Winamp supports TwinVQ playback via a plugin. Some other software that supports TwinVQ but no longer is maintained includes Yamaha's encoder and player and K-Jöfol audio player.