Friday, January 21, 2011

ZL3IN Conversation Video

Here's the video of the ZL3IN contact. Remember, this is just raw UDP packets over the internet, with no error correction, and you're hearing the Codec2 audio just as it was transmitted in the conversation.

Monday, January 17, 2011

Codec2 QSO With ZL3IN

Over the weekend I had a half-hour conversation with Paul, ZL3IN, using Codec2. Paul corrected an error in the script I've published, and we were thus able to hear each other.

His side of the conversation encoded in Codec2 is available here; you can get my side here. I've also mixed the two into a wav file.

Details and a video will follow.

Codec2 Call Testing Service

If I haven't been using Skype for a while, I check that everything is working properly using their 'Call Testing Service'. This service tells you to record a message, then plays it back.

Thinking that this would be great for testing a codec2-over-udp setup, I’ve been playing with a similar service, using this script:

ncat –udp -l \$LOCAL_HOST \$LOCAL_PORT –sh-exec ‘netstat -nu | grep
\$LOCAL_HOST:\$LOCAL_PORT | head -1 | cut -c 45-57 > /tmp/out.ip ;
timelimit -t10 -T1 cat > /tmp/out.c2 ; cat /tmp/morig.c2 /tmp/out.c2 >
/tmp/out2.c2 ; ncat –udp \`cat /tmp/out.ip\` \$LOCAL_PORT < /tmp/out2.c2'

Thursday, January 13, 2011

Codec2 One-way Contact

Simon took me up on my offer in the last post, and after a bit of fiddling, I could hear his codec2-encoded voice reach across the Internet from Crowsnet Pass in Alberta to the Bay of Fundy. Great fun!

Wednesday, January 12, 2011

CQ Codec2, Calling CQ Codec2

Over the holidays, I developed a bash script that allows to computers to communicate with codec2-encoded audio using UDP packets.

The script, called, doesn't do any of the firewall-punching magic that Skype etc. perform. But it should be useful in testing lightweight linux contexts, especially those without a GUI, since it comprises pipelines built from pretty standard Unix tools.

Who'd like to arrange a QSO?