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Re: [Wlug] Audio processing question
by Andy Stewart Dec. 27, 2015

Dec. 27, 2015

On 12/27/2015 01:01 PM, Andy Stewart wrote: > Here's a command that works, to give you a feel for the data formats > involved: > > gqrx outputs RAW audio data to UDP port 65535 > netcat -l -u 65535 | aplay -r 48k -f S16_LE -t raw -c 1 > correct audio is heard > > Now, I want to get that into a WAV file or perhaps a fifo from which the > mondiale decoder could get its input. > > netcat -l -u 65535 | sox ??? > > The man page for sox is not for the faint of heart, and I'm not an audio > expert. > > Any ideas? > > Thanks! > > Andy > Closer: nc -l -u 65535 | sox -r 48k -b 16 -c 1 -L -e signed -t raw - \ -t wav radio.wav ...but....the mondiale decoder doesn't like reading radio.wav: sox WARN wav: Length in output .wav header will be wrong since can't seek to fix it.. Still plugging away...... Andy -- Andy Stewart (KB1OIQ) Founder: Worcester Linux Users' Group Founder: Chelmsford Linux Meetup Group President: PART of Westford, MA (WB1GOF)

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Re: [Wlug] Audio processing question
by Andy Stewart Dec. 27, 2015

Dec. 27, 2015

On 12/26/2015 07:32 PM, Andy Stewart wrote: > On 12/26/2015 06:17 PM, Frank Sweetser wrote: >> I'd bet that you could use netcat do listen ona socket and dump the results directly to a file. OK, I'm getting closer. It turns out that the UDP audio stream is RAW. The "mondiale decoder" wants to see WAV data. I think I need the correct incantation of the sox command. Here's a command that works, to give you a feel for the data formats involved: gqrx outputs RAW audio data to UDP port 65535 netcat -l -u 65535 | aplay -r 48k -f S16_LE -t raw -c 1 correct audio is heard Now, I want to get that into a WAV file or perhaps a fifo from which the mondiale decoder could get its input. netcat -l -u 65535 | sox ??? The man page for sox is not for the faint of heart, and I'm not an audio expert. Any ideas? Thanks! Andy -- Andy Stewart (KB1OIQ) Founder: Worcester Linux Users' Group Founder: Chelmsford Linux Meetup Group President: PART of Westford, MA (WB1GOF)

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Re: [Wlug] Audio processing question
by John Stoffel Dec. 27, 2015

Dec. 27, 2015

>>>>> "Andy" == Andy Stewart <andystewart(a)comcast.net> writes: Andy> What I want to do is listen to the DRM broadcast in real time. I was Andy> unsuccessful in getting Dream to read the WAV file while it was being Andy> written. >> Andy> Does anybody have any suggestions as to how this could be done? >> >> Have you tried setting up a FIFO that each program opens and treats as >> a WAV file? That might be the way to have them talk to each other. >> >>> mkfifo /var/tmp/radio >>> gqrx --output /var/tmp/radio >>> mondiale --input /var/tmp/radio >> >> though I havent' a clue what the two programs do at the commmand >> level. Andy> That is an interesting idea but gqrx doesn't let the user pick a Andy> file name for saving the WAV audio. It creates a file name by Andy> an internal algorithm. All I can do is pick the directory in Andy> which that file is saved. Andy> Is there a way that I can tie a file to a UDP port? gqrx will Andy> output an audio stream on a UDP port. If I can make that look Andy> like a file, perhaps "mondiale" will consume it. Hmm... maybe using 'nc' (netcat) to listen to that UDP port and then feed the info into either the FIFO or directly into the other tool? Are they open source? It might just be time to hack some source to do what you want... I also think the JACK audio thing might work, where you setup some virtual Mics and Feeds to connect the two programs together. John

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Re: [Wlug] Audio processing question
by Andy Stewart Dec. 27, 2015

Dec. 27, 2015

On 12/26/2015 06:17 PM, Frank Sweetser wrote: > I'd bet that you could use netcat do listen ona socket and dump the results directly to a file. > I can't try it again until the DRM station broadcasts when I can receive it. I knew I should have recorded the I and Q when I was listening to it! I think this will work (not literally but you get the idea): mkfifo /tmp/radio gqrx > udp:65535 netcat -l -u 65535 > /tmp/radio "mondiale decoder" < /tmp/radio I'll let you know if this works. I'm also open to other suggestions, and still looking at JACK. Andy -- Andy Stewart (KB1OIQ) Founder: Worcester Linux Users' Group Founder: Chelmsford Linux Meetup Group President: PART of Westford, MA (WB1GOF)

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Re: [Wlug] Audio processing question
by Frank Sweetser Dec. 26, 2015

Dec. 26, 2015

I'd bet that you could use netcat do listen ona socket and dump the results directly to a file. On December 26, 2015 6:15:31 PM EST, Andy Stewart <andystewart(a)comcast.net> wrote: > > >Is there a way that I can tie a file to a UDP port? gqrx will output >an >audio stream on a UDP port. If I can make that look like a file, >perhaps "mondiale" will consume it. > >Andy -- Sent from my Android device with K-9 Mail. Please excuse my brevity.

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Re: [Wlug] Audio processing question
by Andy Stewart Dec. 26, 2015

Dec. 26, 2015

On 12/26/2015 04:13 PM, Steve Revilak wrote: >> Hi gang, >> >> I think I need something like the Virtual audio cable, but I'd like to >> know if there are other possibilities. >> >> I have two audio programs that I want to talk to each other: gqrx and >> Dream. > [..] > > > Jack might be worth a try. http://www.jackaudio.org/ > > Steve Thanks, Steve, I'm looking at it but I'm not finding usage examples that tie together two programs. I'll keep looking. Andy -- Andy Stewart (KB1OIQ) Founder: Worcester Linux Users' Group Founder: Chelmsford Linux Meetup Group President: PART of Westford, MA (WB1GOF)

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Re: [Wlug] Audio processing question
by Andy Stewart Dec. 26, 2015

Dec. 26, 2015

On 12/26/2015 05:10 PM, John Stoffel wrote: >>>>>> "Andy" == Andy Stewart <andystewart(a)comcast.net> writes: > > Andy> Hi gang, > > Andy> I think I need something like the Virtual audio cable, but I'd like to > Andy> know if there are other possibilities. > > Andy> I have two audio programs that I want to talk to each other: gqrx and > Andy> Dream. > > Andy> gqrx is a software defined radio receiver that can save its audio as a > Andy> WAV file, or it can stream audio via a UDP port. > > Andy> Dream is a digital radio mondiale (DRM) decoder. Digital radio mondiale > Andy> is a shortwave radio broadcast in a digital format. Dream can read a > Andy> WAV file, or it can read audio information from the microphone. It > Andy> outputs a rather nicely sounding radio broadcast (mono or stereo > Andy> depending on the broadcaster) with no static and no fading. > > Andy> I have succeeded in recording gqrx audio to a WAV file, and later having > Andy> Dream decode it. > > Andy> What I want to do is listen to the DRM broadcast in real time. I was > Andy> unsuccessful in getting Dream to read the WAV file while it was being > Andy> written. > > Andy> Does anybody have any suggestions as to how this could be done? > > Have you tried setting up a FIFO that each program opens and treats as > a WAV file? That might be the way to have them talk to each other. > >> mkfifo /var/tmp/radio >> gqrx --output /var/tmp/radio >> mondiale --input /var/tmp/radio > > though I havent' a clue what the two programs do at the commmand > level. Hi John, That is an interesting idea but gqrx doesn't let the user pick a file name for saving the WAV audio. It creates a file name by an internal algorithm. All I can do is pick the directory in which that file is saved. Is there a way that I can tie a file to a UDP port? gqrx will output an audio stream on a UDP port. If I can make that look like a file, perhaps "mondiale" will consume it. Andy -- Andy Stewart (KB1OIQ) Founder: Worcester Linux Users' Group Founder: Chelmsford Linux Meetup Group President: PART of Westford, MA (WB1GOF)

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Re: [Wlug] Audio processing question
by John Stoffel Dec. 26, 2015

Dec. 26, 2015

>>>>> "Andy" == Andy Stewart <andystewart(a)comcast.net> writes: Andy> Hi gang, Andy> I think I need something like the Virtual audio cable, but I'd like to Andy> know if there are other possibilities. Andy> I have two audio programs that I want to talk to each other: gqrx and Andy> Dream. Andy> gqrx is a software defined radio receiver that can save its audio as a Andy> WAV file, or it can stream audio via a UDP port. Andy> Dream is a digital radio mondiale (DRM) decoder. Digital radio mondiale Andy> is a shortwave radio broadcast in a digital format. Dream can read a Andy> WAV file, or it can read audio information from the microphone. It Andy> outputs a rather nicely sounding radio broadcast (mono or stereo Andy> depending on the broadcaster) with no static and no fading. Andy> I have succeeded in recording gqrx audio to a WAV file, and later having Andy> Dream decode it. Andy> What I want to do is listen to the DRM broadcast in real time. I was Andy> unsuccessful in getting Dream to read the WAV file while it was being Andy> written. Andy> Does anybody have any suggestions as to how this could be done? Have you tried setting up a FIFO that each program opens and treats as a WAV file? That might be the way to have them talk to each other. > mkfifo /var/tmp/radio > gqrx --output /var/tmp/radio > mondiale --input /var/tmp/radio though I havent' a clue what the two programs do at the commmand level.

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Re: [Wlug] Audio processing question
by Steve Revilak Dec. 26, 2015

Dec. 26, 2015

>Hi gang, > >I think I need something like the Virtual audio cable, but I'd like to >know if there are other possibilities. > >I have two audio programs that I want to talk to each other: gqrx and >Dream. [..] Jack might be worth a try. http://www.jackaudio.org/ Steve

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Audio processing question
by Andy Stewart Dec. 26, 2015

Dec. 26, 2015

Hi gang, I think I need something like the Virtual audio cable, but I'd like to know if there are other possibilities. I have two audio programs that I want to talk to each other: gqrx and Dream. gqrx is a software defined radio receiver that can save its audio as a WAV file, or it can stream audio via a UDP port. Dream is a digital radio mondiale (DRM) decoder. Digital radio mondiale is a shortwave radio broadcast in a digital format. Dream can read a WAV file, or it can read audio information from the microphone. It outputs a rather nicely sounding radio broadcast (mono or stereo depending on the broadcaster) with no static and no fading. I have succeeded in recording gqrx audio to a WAV file, and later having Dream decode it. What I want to do is listen to the DRM broadcast in real time. I was unsuccessful in getting Dream to read the WAV file while it was being written. Does anybody have any suggestions as to how this could be done? FYI: reception of DRM broadcasts requires an upper sideband radio receiver that is at least 10kHz wide, a decent antenna, and in my case, a DVB-T dongle and the gqrx software coupled with Dream. Thanks in advance for any help you may provide. Andy -- Andy Stewart (KB1OIQ) Founder: Worcester Linux Users' Group Founder: Chelmsford Linux Meetup Group President: PART of Westford, MA (WB1GOF)

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