Re: [Freetel-codec2] SM1000 - silly question

[Onno B. <on...@it...>]

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 <len...@gm...> 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 <da...@ro...> 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   -
>> > on...@it... <mailto:on...@it...>
>> >
>> >
>> >
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-- 
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   -
on...@it...