After banging my head on the wall for a little while I now have a modicum of success. (Fair warning, a "but" is coming...)
- I have translated a source 256k mp3 into a 16 bit/8k wav file - it loses a little dynamic range, but that is to be expected - I have translated the wav into a raw file using wav2raw.sh - I have used freedv_tx 1600 to "transmit the file" to an encoded.raw file - I have used freedv_rx 1600 to "receive the file" to a decoded.raw file But ... When I play back either the encoded.raw or decoded.raw files (using playraw.sh), I get some interesting results. - The audio level for encoded.raw is pretty low, discernible, but low. - The audio output for the decoded.raw is readable, but nothing at all like the sample files. I can make out what I'm saying, but only because I said it. Can someone please point at the idiot mistake I'm making? o On 23 July 2015 at 17:25, Mark Jessop <[email protected]> wrote: > Onno: We've actually done something similar on the local broadcast (after > the national broadcast). > > I second David's comments above about using the command line modems, will > be far easier. > > One thing to note is the end result is going to depend *heavily* on how > the broadcast gets to air. I know around here that the 'originating' source > of the broadcast (VK5RAD) has some pretty bad audio issues, and some of the > other broadcasts (i.e. 40m) are re-broadcasts of that one, compounding the > issue. > The end result can sound pretty bad, and once you add codec2 modulation > and demodulation to that, it may not come across very well. Just some food > for thought... > > Cheers, > Mark VK5QI > > On Thu, Jul 23, 2015 at 11:11 AM, David Rowe <[email protected]> wrote: > >> Hi Onno, >> >> Yayy, the mailing list is working again! >> >> Good questions. >> >> If you are OK with Linux (and when codec2-dev SVN is alive again), you >> can use the command line freedv_tx/freedv_rx programs to process a wave >> file: >> >> (build codec-dev as per readme) >> $ cd build_linux/src >> $ ./freedv_tx 1600 speech.wav modem_signal.wav >> $ ./freedv_rx 1600 modem_signal.wav speech_decoded.wav >> >> speech.wav should be sampled at 8kHz, 16 bit integer (short) samples, >> mono. >> >> Or send me a wave file you want processed and I'll run it for you. >> >> Cheers, >> >> David >> >> >> On 23/07/15 09:42, Onno Benschop wrote: >> > Hi all, >> > >> > While Andrew Smith (VK6PDQ/VK6AS) is on holiday I have his SM1000 to >> > play with. Nice piece of kit. (I added 4 feet to it, makes it stay on >> > the bench - >> > >> http://www.bunnings.com.au/madico-surface-protection-8mm-vinyl-rnd-clr-23260cf_p3979381 >> ) >> > >> > For an episode* of "What use is an F-call?" - I want to achieve the >> > following: >> > >> > * Record some audio that has been transcoded using CODEC2, so that >> > listeners get a sense of the difference between analogue and digital >> > audio. >> > * Record some digital - non-decoded - audio, so listeners can hear >> > what CODEC2 sounds like on-air. >> > * Record some digital - non-decoded - audio and put it as a >> > "sub-audible" signal underneath some normal analogue audio, so >> > listeners get two information streams for the price of one. >> > >> > I am unclear what audio levels come and go from the SM1000 and I don't >> > want to blow up either ports on the unit or my computer. >> > >> > I have installed FreeDV onto a Debian Wheezy virtual machine. (Running >> > on a Mac, so no "microphone port", just a "line level port". >> > >> > I also have a Heil headset and an audio mixer. >> > >> > I've been trolling the documentation, the wiki and other information, >> > but I'm not clear on how to achieve this electrically. >> > >> > Any pointers would be gratefully accepted. (And when I achieve it, I'll >> > document it, so I won't forget how to do it later ;-) >> > >> > I also came across instructions to compile CODEC2 from source, but I >> > cannot seem to checkout from the repository. Not sure if that is because >> > of the SF outage >> > [ >> http://sourceforge.net/blog/sourceforge-infrastructure-and-service-restoration-update-for-722/ >> ], >> > or because of a configuration problem at my end. >> > >> > Look forward to hearing from you. >> > >> > * Technically, "What use is an F-call?" no longer exists. As of a few >> > months ago it's now called "Foundations of Amateur Radio", but the >> > national news is about a year behind, so nationally this won't be heard >> > for a little while. >> > -- >> > Onno Benschop >> > >> > ()/)/)() ..ASCII for Onno.. >> > |>>? ..EBCDIC for Onno.. >> > --- -. -. --- ..Morse for Onno.. >> > >> > If you need to know: "What computer should I buy?" http://goo.gl/spsb66 >> > >> > ITmaze - ABN: 56 178 057 063 - ph: 04 1219 8888 - >> > [email protected] <mailto:[email protected]> >> > >> > >> > >> ------------------------------------------------------------------------------ >> > >> > >> > >> > _______________________________________________ >> > Freetel-codec2 mailing list >> > [email protected] >> > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >> > >> >> >> ------------------------------------------------------------------------------ >> _______________________________________________ >> Freetel-codec2 mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >> > > > > ------------------------------------------------------------------------------ > > _______________________________________________ > Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > > -- Onno Benschop ()/)/)() ..ASCII for Onno.. |>>? ..EBCDIC for Onno.. --- -. -. --- ..Morse for Onno.. If you need to know: "What computer should I buy?" http://goo.gl/spsb66 ITmaze - ABN: 56 178 057 063 - ph: 04 1219 8888 - [email protected]
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