TwinVQ
From Wikipedia, the free encyclopedia
TwinVQ (transform-domain weighted interleaved vector quantization) is an audio compression technique developed by Nippon Telegraph and Telephone Corporation (NTT). The compression technique has been used in both standardized and proprietary designs.
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[edit] TwinVQ in MPEG-4
In the context of the MPEG-4 audio (MPEG-4 Part 3), TwinVQ is an audio codec optimized for audio coding at ultra low bitrates around 8 kbit/s.
TwinVQ is one of the object types defined in MPEG-4 Audio version 1. This object type is based on a general audio transform coding scheme which is integrated with the AAC coding frame work, a spectral flattening module, and a weighted interleave vector quantization module. This scheme reportedly has high coding gain for low bit rate and potential robustness against channel errors and packet loss, since it does not use any variable length coding and adaptive bit allocation. It supports bitrate scalability, both by means of layered TwinVQ coding and in combination with the scalable AAC.
Note that some commercialized products such as Metasound (Voxware), SoundVQ (Yamaha), and SolidAudio (Hagiwara) are also based on the TwinVQ technology, but the configurations are different from the MPEG-4 TwinVQ.
[edit] TwinVQ as a proprietary audio format
A proprietary audio compression format called TwinVQ was developed by Nippon Telegraph and Telephone Corporation (NTT) and marketed by Yamaha under the name SoundVQ. Its file extension is .vqf.
TwinVQ uses Twin vector quantization. The proprietary TwinVQ codec supports constant bit rate 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.
[edit] Software support
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[1]. Some other software that supports TwinVQ but no longer is maintained includes Yamaha's encoder and player and K-Jöfol audio player.
If you are using GNU/Linux or similar system, your best shot is to get the XMMS plugin.
