Variable bitrate
Operation where the bitrate varies with time during the decoding of a compressed bitstream.
    Although variable bit rate is acceptable for plain linear playback, one important consideration not to use variable bit rate is that reasonably quick random access becomes nearly impossible.
    There is no table of contents or index in MPEG. The only tool the play back system has for approximating the correct byte position is the requested play back time stamp and the bit rate of the MPEG stream. MPEG streams do not encode their play back time. To approximate an intermediate position in a variable bit rate stream, the play back system must grope around near the end of the stream to calculate the playback time, and assume the stream is approximately constant bit rate. The groping around for the correct position can take several seconds.


VBR
Variable bitrate.


VLC (Variable Length Coding)
A reversible procedure for coding that assigns shorter code-words to frequent events and longer code-words to less frequent events.


VQF
File extension of TwinVQ files.