[amsat-bb] Video: very low bitrate digital voice communications

Bruce Robertson ve9qrp at gmail.com
Fri Jan 21 18:25:56 PST 2011

I'm sure many of you are very interested in the current state of
Codec2, the open-source, low-bitrate voice codec that is being led by
David Rowe VK5DGR. If so, I'd like to draw your attention to the
following video that ZL3IN and I made over the past weekend, which
comprises the actual audio of our first meeting over the Internet,
using codec2 bitstreams. I hope you'll agree that this alpha-level
software is very usable right now:


Our conversation was conducted using a bash script that I wrote to
provide simple codec2 voice communication over the Internet. Since
October, I've been spending what would normally be my ham time working
on that, or trying to help improve the c2 performance on low-power

Codec2 could be very important to AMSAT's future. Running currently at
2500 bps, and aiming for 2400 bps with FEC, it could make satellite
voice communication comprise a smaller bandwidth, offering less
demanding downlink systems. Because it is open source, the codec could
even be implemented in the satellite, perhaps to provide voice-encoded
telemetry for a FUNcube-like project of the future.

The Codec2 site is http://www.rowetel.com/blog/?page_id=452

The source files of my conversation with ZL3IN, and many ancillary c2
materials are available on my blog:

73, Bruce

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