Reply by Steve Underwood September 27, 20062006-09-27
Hi all,

RFC3551 defines the way in which the output from a number of codecs 
should be packed into RTP packets. Amongst these is the DVI ADPCM codec, 
commonly found on PCs. They refer to this as DVI4. Also, there is VDVI, 
which is a kind of run length encoded variable bit rate version of DVI. 
They quote some low potential numbers for its bit rate, which don't seem 
to make sense. The 4 bit codes from the DVI codec are fairly white, so I 
really can't see how run length encoding helps in any way. Even a small 
background noise in periods of "silence" exercises all the 4 bit codes 
from the codec fairly evenly. Has anyone seen VDVI used in a real