Open Source DMR Modem Implementation in SDR with GNU Radio and Codec2

https://qradiolink.org/open-source-DMR-transceiver-implementation.html

#HackerNews #OpenSource #DMR #SDR #GNURadio #Codec2 #DigitalCommunications

@ustralien and even then:

Modern #Codecs like #Speex and espechally #Opus really work great on #Mumble and other solutions like #WebCall and #SIP-Clients like #Linphone.

• Unless you're stuck on #Iridium, then #Codec2 is the only thing narrowband-efficient enough to work at all...

@herrorange Already existing options do that better than the old #SILK codec.

• #Linphone (#SIP client) supports #Opus & #Speex, which can do better at narrower bandwiths)

• #Codec2 OFC can work even on #Iridium-level bandwiths

• #Mumble, #WebCall & #JitsiMeet also do fine on #Skype-able bandwiths and don't require a T H I C C install on peoples' devices...

I mean, I don't expect a #Tablet to have good #Audio quality.

• Frankly I'd be content with #Codec2-level #AMR since no carrier properly implements #AMRWB anyway. Everyone who even halfasses #AudioQuality will plug in a headset anyway...

But being able to just chug in a #SIM and test it by calling it is something people do need rather often!

• Even if it's just for a few calls like booking a data package on the go!

https://infosec.space/@kkarhan/113865596661922371

Playing around with FreeDATA (https://freedata.app/) app on 40 meters. What a nice modern application, can operate keyboard-to-keyboard QSO's and leave messages from a remote PC using a webbrowser. Seems like a nice modern alternative to #JS8CALL. It's based on the open source #Codec2 which is also used for #FreeDV and #M17. No need for proprietary software modems like #VARA anymore. If you like stuff like #VarAC or #JS8 give this a try! #hamradio #ham #freedata

@xssfox personally, I think #Codec2 is pretty awesome given it's a #FLOSS codec that can work with as little as 450bit/s, making #DigitalVoice via #Moonbouce possible!

@pawagner in this case the person was (presumably amidst the background noise) in a callcenter and refused to acknowledge it's their fault and responsibility to not have noise AND legible audio quality.

#Iridium (#AMBE) #NATO-Radio (#MELP & #MELPe) and even #Codec2 is more legible than they were...

@DO9XE @hikhvar @srslypascal @nicoduck @stahlmann @mimrma Wüsste nicht dass #Verschlüsselung verboten sei.

#Datenfunk nur auf den zugewiesenen Kanälen und die Frequenzzuteilungsbedingungen sind einzuhalten.

• Inkl. Konformität der Funkgeräte und keine Dauersendungen...

Bei #Amateurfunk-Frequenzen ist Verschlüsselung verboten und offene Standards vorgeschrieben, weshalb #Codec2 entwickelt wurde...

@Gankra depends...

xz and lzma2 are pretty good when it comes to compression ratio, and with modern hardware they are sufficiently fast.

• But there's a reason a lot of stuff, like online games, use bz2 instead, since that allows speeds in excess of 600 Mbit/s even on low-end systems with minimal load, and in my experience allows compression of backups like #PostgeSQL's cluster_backup at basically I/O speeds with <10% CPU load even at very old servers...

So there's that...

AFAICT xz is basically at the limit of lossless data compression - anything more efficient I know are extremely lossy narrowband codecs like #Codec2 @450 bit/s TWELP @ 300 bit/s and #STANAG4591 aka. MELPe that sound like one has their ears filled with water and the person talking has a gag ball in their mouth and screams.

@landley The sad part is that you are in fact correct.

The only thing #Copyleft like #GPLv3, #AGPLv3 and espechally #AssholeLicensing of the #SSPL, #RHEL and #grsecurity kind can do is commit #AssetDenial and even that is flaky as one can only put actual #code under a license and not an implementation of something like a #Codec...

...But those are usually covered by #patents and other legalese trolling efforts, like the way #MELP / #MELPe is licensed so everyone who doesn't want to exclusively make a radio for NATO / U.S. DoD has to arrange a licensing deal woth half a dozen tech giants, so #Codec2 had to be made...
https://en.wikipedia.org/wiki/Mixed-excitation_linear_prediction
https://en.wikipedia.org/wiki/Codec_2

As of now I am considering to relicense my content under #0BSD and sinve very few of my projects have any external contributions, this should be trivial to do so.

@m17_project solder the header pins and Waveshare LCD to my #Module17 board and flashed the latest @openrtx firmware.

#hamradio #digital #M17 #codec2 #OpenRTX

@m17_project #Module17 boards arrived today along with some #rs232 breakouts. the soldering and stuff looks very well done, very nice looking boards. Just waiting for the waveshare LCDs to arrive.

#hamradio #digital #codec2

@lazerwalker I guess it'll try to find some "satanic lyrics" in it...

I wounder how well it handles extremely agressive #vocoders like #TWELP, #MELPe or #Codec2...

Break Free from Proprietary Digital Radio https://hackaday.com/2023/08/05/break-free-from-proprietary-digital-radio/ #amateurradio #digitalvoice #RadioHacks #reflector #hamradio #standard #codec2 #audio #codec #radio #m17

@vk6flab @jupiter for the condition of "static lossless #compression" the bar is extremely low.

OFC it won't be even remotely efficient when compared to modern compression...
Even #LZ77 will run circles around it, not to mention #bzip2, #lzma or high-efficiency vocoders like #Codec2....

https://mstdn.social/@kkarhan/110692504545982742

@niconiconi hmmm……想发点 #CODEC2 编码的东西都不行……

玩了一个通宵的 #CODEC2 ，一部 11 个半小时的有声读物在 2.4k 的配置下出来的数据量只有不到 12MiB ！就是没想好怎么分享出来，作为文件还是大了点……😂