More experimentation -- I've decoded the sound to a wav file, trimmed
the samples, played the trimmed wav file, then encoded the wav back into
codec2.  The (much shorter) wav file degrades when re-encoded, but plays
back correctly as a wav file.

-- 
  Imran
  [email protected]

On Tue, Jul 19, 2016, at 01:39 PM,
[email protected] wrote:
> Send Freetel-codec2 mailing list submissions to
>       [email protected]
> 
> To subscribe or unsubscribe via the World Wide Web, visit
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> or, via email, send a message with subject or body 'help' to
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> 
> When replying, please edit your Subject line so it is more specific
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> 
> 
> Today's Topics:
> 
>    1. USB interface with codec2 (Faisal Saleem)
>    2.  coding question (Alan Beard)
>    3. Re: coding question (Brady O'Brien)
>    4. Re: coding question (Jeroen Vreeken)
>    5. Empty noise trimming causes sound degradation? (Imran)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Fri, 15 Jul 2016 07:42:11 +0000 (UTC)
> From: Faisal Saleem <[email protected]>
> Subject: [Freetel-codec2] USB interface with codec2
> To: "[email protected]"
>       <[email protected]>
> Message-ID:
>       <[email protected]>
> Content-Type: text/plain; charset="utf-8"
> 
> 
>   Hi all,
>  I am an engineering student and working on a digital voice project. I am
>  impressed by codec2 and sm1000, the freedv adapter. I just got 2 sm1000
>  modules and built the firmware sm1000.bin successfully. 
>  My questions are:1) how can i apply codec2 on Recorded voice or Audio
>  file which is stored in USB? My query is how? i access? from USB a Audio
>  file.
> how can i do?
> 
> Thanks in advance for your precious help??Regards,
> Faisal Saleem
> 
> Email :[email protected]?, [email protected]:
> 0092-305-7733854
> -------------- next part --------------
> An HTML attachment was scrubbed...
> 
> ------------------------------
> 
> Message: 2
> Date: Sat, 16 Jul 2016 19:45:41 +1000
> From: "Alan Beard" <[email protected]>
> Subject: [Freetel-codec2]  coding question
> To: [email protected]
> Message-ID: <[email protected]>
> Content-Type: text/plain; charset="utf-8"
> 
> Hi all,
> 
> Can the Codec2 code be split into two sections?
> 
> 1) From and to the radio audio. To be put into a dedicated DSP device,
> see the MMDVM project, Arduino DUE.
> 
> 2) Human side, microphone and speaker, digital to audio and back, to be
> done on a full Linux or Windoze system.
> 
> A good project for you Faisal Saleem.
> 
> Alan VK2ZIW
> 
> On Fri, 15 Jul 2016 07:42:11 +0000 (UTC), Faisal Saleem wrote
> > 
> >   Hi all,
> > I am an engineering student and working on a digital voice project. I am 
> > impressed by codec2 and sm1000, the freedv adapter. I just got 2 sm1000 
> > modules and built the firmware sm1000.bin successfully. 
> > 
> > My questions are:
> > 1) how can i apply codec2 on Recorded voice or Audio file which is stored 
> > in USB? My query is how? i access? from USB a Audio file.
> > 
> > how can i do?
> > Thanks in advance for your precious help
> > ?
> > ?Regards,
> > 
> > Faisal Saleem
> > 
> > Email :[email protected]?, [email protected]
> > Cell: 0092-305-7733854
> 
> Alan
> 
> Evil flourishes when good men do nothing. 
> Consider Jesus. 
> --------------------------------------------------------------------------- 
> Alan Beard ? ? ? ? ? ? ? Unix Support Technician from 1984 to today 
> 70 Wedmore Rd. ? ? ? ? ? Sun Solaris, AIX, HP/UX, Linux, SCO, MIPS 
> Emu Heights N.S.W. 2750 ?Routers, terminal servers, printers, terminals
> etc.. 
> +61 2 47353013 (h) ? ? ? Support Programming, shell scripting, "C",
> assembler 
> 0414 353013 (mobile) ? ? After uni, electronics tech
>  
> -------------- next part --------------
> An HTML attachment was scrubbed...
> 
> ------------------------------
> 
> Message: 3
> Date: Sat, 16 Jul 2016 21:21:20 +1000
> From: "Brady O'Brien" <[email protected]>
> Subject: Re: [Freetel-codec2] coding question
> To: [email protected]
> Message-ID:
>       <cac_maihxteum16r49hpp3qsdsepn8uwug-h1mgpulxftw9p...@mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Hi Alan,
> 
> It would be possible to split the modem end of freedv
> (fdmdv,cohpsk,fsk,fmfsk) from the codec end. Currently, however, this is
> not really supported by the freedv API (freedv_api.c/.h). If anyone is
> interested in doing this for any freedv modes, freedv_api.c and
> freedv_api.h are good places to look.
> 
> Thanks,
> 
> Brady O'Brien
> 
> On Sat, Jul 16, 2016 at 7:45 PM, Alan Beard <[email protected]>
> wrote:
> 
> >
> >
> >
> >
> >
> >
> >
> >
> > *Hi all, Can the Codec2 code be split into two sections? 1) From and to
> > the radio audio. To be put into a dedicated DSP device, see the MMDVM
> > project, Arduino DUE. 2) Human side, microphone and speaker, digital to
> > audio and back, to be done on a full Linux or Windoze system. A good
> > project for you *
> >
> >
> >
> >
> > *Faisal Saleem. Alan VK2ZIW On Fri, 15 Jul 2016 07:42:11 +0000 (UTC),
> > Faisal Saleem wrote*
> > >
> > > <[email protected]> Hi all,
> >
> > > I am an engineering student and working on a digital voice project. I am
> > impressed by codec2 and sm1000, the freedv adapter. I just got 2 sm1000
> > modules and built the firmware sm1000.bin successfully.
> > >
> > > My questions are:
> > > 1) how can i apply codec2 on Recorded voice or Audio file which is
> > stored in USB? My query is how  i access  from USB a Audio file.
> > >
> > > how can i do?
> > >
> > Thanks in advance for your precious help
> > >
> > >  Regards,
> > >
> > > *Faisal Saleem*
> > >
> > > Email : [email protected] , [email protected]
> > <[email protected]>
> > > Cell: 0092-305-7733854
> >
> >
> > Alan
> >
> > Evil flourishes when good men do nothing.
> > Consider Jesus.
> > ---------------------------------------------------------------------------
> >
> > Alan Beard               Unix Support Technician from 1984 to today
> > 70 Wedmore Rd.           Sun Solaris, AIX, HP/UX, Linux, SCO, MIPS
> > Emu Heights N.S.W. 2750  Routers, terminal servers, printers, terminals
> > etc..
> > +61 2 47353013 (h)       Support Programming, shell scripting, "C",
> > assembler
> > 0414 353013 (mobile)     After uni, electronics tech
> >
> >
> > ------------------------------------------------------------------------------
> > What NetFlow Analyzer can do for you? Monitors network bandwidth and
> > traffic
> > patterns at an interface-level. Reveals which users, apps, and protocols
> > are
> > consuming the most bandwidth. Provides multi-vendor support for NetFlow,
> > J-Flow, sFlow and other flows. Make informed decisions using capacity
> > planning
> > reports.http://sdm.link/zohodev2dev
> > _______________________________________________
> > Freetel-codec2 mailing list
> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/freetel-codec2
> >
> >
> -------------- next part --------------
> An HTML attachment was scrubbed...
> 
> ------------------------------
> 
> Message: 4
> Date: Sun, 17 Jul 2016 17:53:29 +0200
> From: Jeroen Vreeken <[email protected]>
> Subject: Re: [Freetel-codec2] coding question
> To: [email protected]
> Message-ID: <[email protected]>
> Content-Type: text/plain; charset=windows-1252
> 
> 
> On 07/16/2016 01:21 PM, Brady O'Brien wrote:
> > Hi Alan,
> >
> > It would be possible to split the modem end of freedv
> > (fdmdv,cohpsk,fsk,fmfsk) from the codec end. Currently, however, this
> > is not really supported by the freedv API (freedv_api.c/.h). If anyone
> > is interested in doing this for any freedv modes, freedv_api.c and
> > freedv_api.h are good places to look.
> >
> Actually, I think the codecrx() and codectx()/datatx() functions do
> exactly what Alan wants.
> 
> Regards,
> Jeroen
> 
> 
> 
> 
> ------------------------------
> 
> Message: 5
> Date: Tue, 19 Jul 2016 13:21:33 -0700
> From: Imran <[email protected]>
> Subject: [Freetel-codec2] Empty noise trimming causes sound
>       degradation?
> To: [email protected]
> Message-ID:
>       <1468959693.3939434.670997161.7d178...@webmail.messagingengine.com>
> Content-Type: text/plain
> 
> Hi All,
> 
> I've been experimenting with Codec2 for voice reconstruction.  I've
> found something odd.
> 
> I have a ~2 second long wav file, 8 Khz, 16 bit pcm, mono.  I can encode
> this file into codec2 no problem.
> The first 1.3 seconds is silence.  The mic is on, but in a quiet room
> with no noise.  The wav file spectogram shows a flat line, near 0, with
> just a little white noise, for these 1.3 seconds, followed by a quiet
> envelope of speech sounds.
> 
> So, I encode the wav file into codec2, decode it and playback.  Sounds
> fine.
> Then, I start deleting frames at the head of the encoding.  So, I delete
> frame 0, then frame 1 .. frame 15.  That's about 300 ms of sound I've
> removed that has no human sounds in it -- just mic whitenoise.
> 
> Then, something weird happens.
> While there's still a lot of silence in the playback, when playback
> reaches the speech, the voice is noticeably degraded.
> 
> I can delete 10 frames, no problem.  When I delete more than 10,
> degradation starts, and increases as I delete more frames. 
> 
> Anyone have any hints on why?
> 
> Thanks,
> Imran
> -- 
>   Imran
>   [email protected]
> 
> 
> 
> ------------------------------
> 
> ------------------------------------------------------------------------------
> What NetFlow Analyzer can do for you? Monitors network bandwidth and
> traffic
> patterns at an interface-level. Reveals which users, apps, and protocols
> are 
> consuming the most bandwidth. Provides multi-vendor support for NetFlow, 
> J-Flow, sFlow and other flows. Make informed decisions using capacity
> planning
> reports.http://sdm.link/zohodev2dev
> 
> ------------------------------
> 
> _______________________________________________
> Freetel-codec2 mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/freetel-codec2
> 
> 
> End of Freetel-codec2 Digest, Vol 75, Issue 7
> *********************************************

------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are 
consuming the most bandwidth. Provides multi-vendor support for NetFlow, 
J-Flow, sFlow and other flows. Make informed decisions using capacity planning
reports.http://sdm.link/zohodev2dev
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