codec2 VS minimodem

I'm currently working on a 2HD floppy disk release of a podcast episode which has taken me down an interesting rabbit hole of low-bitrate audio codecs, floppy disk aesthetics and label design.

The episode I'm releasing is 1h40m long, which sounds like it couldn't possibly fit in 1.44MB, but there's an obscure but free codec mostly used by digital HAM radio enthusiasts called Codec2 [1] which can encode human voice in as low as 700bit/s (roughly 315KB/hr). At that quality setting it sounds like complete garbage, although still barely intelligible, and there are no readily available media players for the it (there's not even an established file format) so I'm having to include complicated ffmpeg instructions in a README to get people to play it, but I think it all adds to the charm.

Funnily enough after searching for days for how to fit the original episode in a floppy (tried low-bitrate MP3, Opus and AAC, all of which fail at the task), and after discovering Codec2 almost by chance, I only then came across an article called "Codec2: a whole Podcast on a Floppy Disk" [2] which I probably would've found if I had started by searching "podcast in a floppy".

[1] https://github.com/drowe67/codec2

[2] https://auphonic.com/blog/2018/06/01/codec2-podcast-on-flopp...

1.5 kbps speech is impressive, I wonder how it compares with Codec2 https://github.com/drowe67/codec2

David Rowe has some information on doing this kind of testing here: https://github.com/drowe67/codec2/blob/master/README_fsk.md

You have a chance with codec2, but I wouldn't expect it to handle any real-time communication. This codec only works for voice, for anything else it's trash.

You also got some samples available at http://www.rowetel.com/codec2.html

This will get you started:

Tony Fisher wrote V.32 soft modem stack for SGI Indy back in 1996. York University couldnt handle hosting whole 8 megabytes of his stuff https://www.cs.york.ac.uk/news/fisher/home-page but at least they had the decency to upload it to github instead of just deleting https://github.com/university-of-york/cs-www-users-fisher/tr... Randy Rossi rewrote this project and got working V.21/23 https://github.com/randyrossi/fisher-modem

Fabrice Bellard, because of course he did :), implemented his own version all the way to V.34 with parts of V.90 https://bellard.org/linmodem/

V.21 modem implemented in Gnu Radio https://web.archive.org/web/20170627151353/http://aaronscher...

amodem - good source of ready made modulation implementations https://github.com/romanz/amodem

minimodem- simple radio link FSK modem https://github.com/kamalmostafa/minimodem

audsl - leased line project, not compatible with standard modems https://www.araneus.fi/audsl/ but might give some ideas.

Try downloading it from the tags section instead of cloning the repo. https://github.com/kamalmostafa/minimodem/tags

there's a tool called minimodem http://www.whence.com/minimodem/ it uses audio cards to replicate ancient modem standards - I was watching videos of old modems and was able to use minimodem to simultaneously reconstruct the terminal session locally. It was amusing to do so.

“What do you do when you cannot copy text between computers due to lack of internet connectivity? “

Literally what Minimodem was created for :)

http://www.whence.com/minimodem/