DISQUS

In more than one SF story published decades ago, Robert A. Heinlein had characters transfer audio recordings quickly by "zip-squeal," "60-to-one audio transmission." Of course, Heinlein's original vision of the technology was likely analog (and curiously, if you think about it, assumed his characters could employ a wire or radio channel having a bandwidth of 180 KHz or more, rather than the 3 KHz of a normal telephone line). There were buffers at both ends (such as variable-speed tape).

However(!) Heinlein explicitly added a digital receiving buffer for high-speed audio in The Moon Is A Harsh Mistress (GP Putnam's Sons, 1966). In that book, the narrator, Mannie Davis, asks his self-aware-computer friend, Mike, to allocate a digital memory buffer, "ten-to-the-eighth bits capacity" to receive and store time-compressed audio (along with other data). Mannie then sends Mike compressed audio through a high-bandwidth (and binaural, i.e., stereo) telephone channel, for later playback and analysis at normal speed. There's no question that Heinlein knew about analog-to-digital conversion; in the book he discusses Mike's vocoder and voder (codec) circuits. Indeed, Mannie builds a 20-channel codec for Mike so he can carry on more than one conversation at a time.

Once Ampex invented practical video tape recording, transmitting time-compressed taped video in the same fashion as time-compressed taped audio would have been obvious. (It would also, obviously, have required a heck of a lot of bandwidth, but that's merely a cost-constraint, not a conceptual gap.)

Anyway, Heinlein didn't claim to have invented time-compressed audio transmission. I don't know who did, but it was already in use in the 1950's for radio transmissions by spies, submarines, and so-forth, to frustrate attempts to locate the transmitter by radio direction-finding (by minimizing the time DF'ers would get to take bearings on the transmitted signal).