tj@xn.ll.mit.edu (Thomas E. Jones) (11/16/90)
I'm a little surprised no one has talked about the low data-rate speech vocoding algorithms that have been developed. Here at the laboratory, we implemented a real-time 300 Baud algorithm developed at BBN called an LPC segment vocoder. Yes, it takes a lot of computation to do it in real time, and a lot of computer hardware, but shows that low data rates are possible, and there remains lots of work to be done on improving these. A new vocoding algorithm known as Sinusoidal Coding has been developed by the same group at Lincoln Lab., and offers much better voice quality than LPC. I'm no expert in this area, but can point people toward references if anyone's interested. - tj@xn.ll.mit.edu -- tj@xn.ll.mit.edu or tj@ll-xn.arpa (one of these should work) Thomas E. Jones, home (617) 924-8326 work (617) 981-5093
wilf@sce.carleton.ca (Wilf Leblanc) (11/16/90)
tj@xn.ll.mit.edu (Thomas E. Jones) writes: >I'm a little surprised no one has talked about the low data-rate >speech vocoding algorithms that have been developed. Me too. I thought with all the net bandwidth regarding compression to 'walkman' quality, someone would have brought this up. Maybe not walkman quality, but at least it is 'intelligable' (at a very low data rate). >[stuff deleted regarding segment vocoder @ 300 bps] There is alot of literature regarding 'vocoders' at 300 (or so) bps. Basically, most of them are an LPC vocoder (LPC10 type) with Vector Quantization of the LPC parameters and so on. See ICASSP around 1980-1984. Not (as) much written on it since then (to my knowledge). >A new vocoding algorithm known as Sinusoidal Coding has been >developed by the same group at Lincoln Lab., and offers much better voice >quality than LPC. Hmmmmm. Correct me if I'm wrong, but I thought Sinusoidal (Transform) coding was a (relatively) old technique which is becoming more popular due (mostly, if not entirely) to the work of McAuley and Quateri (my apologies if their names are spelled wrong, but this is on memory). >[.....] > - tj@xn.ll.mit.edu >-- >tj@xn.ll.mit.edu or tj@ll-xn.arpa (one of these should work) >Thomas E. Jones, home (617) 924-8326 work (617) 981-5093 -- --- Wilf LeBlanc Systems and Computer Eng. Internet: wilf@sce.carleton.ca Carleton University UUCP: ...!uunet!mitel!sce!wilf Ottawa, Ont, Canada