[foms] Proposal: adaptive streaming using open codecs

[Timothy B. Terriberry]

> Can you explain what's a LSP extrapolation ? A quick google doesn't
> give anything.

Probably because I meant LPC (linear prediction coefficients), not LSP 
(line spectral pairs). The concepts are related.

Vorbis, for example, already uses LPC extrapolation to pad the first and 
last MDCT blocks, since blocks are overlapped, but there's no real data 
to overlap with at the beginning and end of a track. Code starts at 
https://trac.xiph.org/browser/trunk/vorbis/lib/block.c#L416