Digital Radio Mondial - audio codec needed

Short wave receiver discussion
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daveB
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Digital Radio Mondial - audio codec needed

Post by daveB » 27 Feb 2015 19:18

I've found the DRM decoder installed it and was successfully receiving it on 5940 kHz from 1800-1900 transmitting in AAC+ - except that it says "no audio codec found" - so no sound. Turns out that due to licencing issues they can't distribute the AAC codecs! So you have to build your own. Can anyone tell me what the instructions on this web site mean? http://drm.sourceforge.net/wiki/index.p ... AC_decoder As far as I'm concerned it may as well be Martian as it appears to assume you know how to do coding.

Or does anyone actually have a working codec and instructions as to how I can implant it into the DRM program folder on my PC.

I'd love to actually hear the audio - and it strikes me as weird that if DRM want to promote digital radio on shortwave they don't make it easy for hobbyists - even if they were to charge you a (small) fee for a ready-built codec!

Rgds

David
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

satnipper
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Location: Western Europe

Re: Digital Radio Mondial - audio codec needed

Post by satnipper » 27 Feb 2015 22:15

It seems to me that folk on this forum are not Googling enough. Like the boy with the noisy PC supply unit the answers are all out there if you frame your Google query correctly!

Work that Google!

Stuart

daveB
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Joined: 07 Oct 2014 16:49

Re: Digital Radio Mondial - audio codec needed

Post by daveB » 27 Feb 2015 22:27

I have googled till my eyeballs want to fall out. Would be grateful if you would share with me the correct phraseology to find an actual codec that works or explains how to interpret the webpage that promised instructions on how to build the codec. Ta :? I thought "aac+ codec for Digital Radio Mondial" would have been quite unambiguous

David
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

satnipper
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Re: Digital Radio Mondial - audio codec needed

Post by satnipper » 28 Feb 2015 00:17

I must admit the Dream application(s) (and I had three versions) were amongst the apps I did not migrate to the new PC last year. I consider DRM to be licensed QRM and the sooner it dies the better. I'd rather listen to my illicit eBay obtained recordings of Wigan Andy playing the spoons in local hostelries than legitimize DRM. However that's just my opinion....

Googling "drm dream aac codec" gives a host of information including the top link to a Dream V1.13 which has the required dlls. Hell - I'll save you the Google it's at http://www.b-kainka.de/Dream.zip

I seem to recall that Dream V1.12 was the one I used and that 1.17 never did work.

Happy drming

Stuart

daveB
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Re: Digital Radio Mondial - audio codec needed

Post by daveB » 28 Feb 2015 14:12

Thanks Stuart,

I had downloaded Dream 2.1.1 from drm.sourceforge.net. I've tuned into the Sinhala service on 15050 KHZ - and this version shows "no codec available" for AAC+. The version you pointed me to shows AAC+ Mono (20.88kbps). Although I've routed the sound to the soundcard output or the primary playback device I get silence. I don't know however how strong the signal needs to be for it to decode - currently it's showing two greens and a red. Does that mean it is below the threshold.

It's not btw that I intend to listen to DRM broadcasts - but as it's thereand is supposed to be brilliant I wanted to try it out - it doesn't seem to have gained a lot of popularity since I was first shown a DRM receiver a few years ago.

Rgds

David
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

satnipper
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Joined: 03 Oct 2014 12:58
Location: Western Europe

Re: Digital Radio Mondial - audio codec needed

Post by satnipper » 28 Feb 2015 16:28

Whenever I've played with Dream in the past I have needed a very strong signal to get audio. Brilliant? I think not.

Stuart

daveB
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Joined: 07 Oct 2014 16:49

Re: Digital Radio Mondial - audio codec needed

Post by daveB » 28 Feb 2015 18:05

Well I've no got another DRM signal. All three bars and green and ..silence...

I think I'll go and find something more rewarding to do.
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

satnipper
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Joined: 03 Oct 2014 12:58
Location: Western Europe

Re: Digital Radio Mondial - audio codec needed

Post by satnipper » 28 Feb 2015 21:37

For what it's worth (and it ain't worth much) my Elad FDM-S2 is occasionally giving audio on 6030. The signal is S9+10 and the decode is extremely unreliable.

DRM is a complete waste of time and effort. Can't believe I'm even checking this out...Good job the rugby is finished for the day.

Stuart

daveB
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Re: Digital Radio Mondial - audio codec needed

Post by daveB » 01 Mar 2015 10:10

Thanks Stuart - saves me wasting any more time on it.

David
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

dxradiofan
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Re: Digital Radio Mondial - audio codec needed

Post by dxradiofan » 08 Mar 2016 23:04

Huh so there is actually something to listen to again in Euriope / UK in DRM mode ? It's a shame all the MW stuff died, I remember how good TDF from Paris sounded on 999khz :--

https://www.youtube.com/watch?v=7ESyF6cIMRY

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Julian Hardstone
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Re: Digital Radio Mondial - audio codec needed

Post by Julian Hardstone » 09 Mar 2016 00:25

I briefly played with DRM ten years ago and I should have v1.5 archived on my old pc if it will still run. The original download link which I posted on the Yahoo MF Group has long gone.
How are you feeding your decoder? The earlier versions required to be fed with raw RF at a low "IF" within the range of your soundcard, and 12kHz was typically used. To get this it is necessary to offset your CIO/BFO by 12kHz and ensure that the audio chain of the rx extends to 20kHz+
I expect that has been superceeded by I-Q outputs from an SDR
I don't recall DRM needing a particularly strong signal to get a decode, but it was very intolerant of QRM or impulse noise, plus it takes 10sec or longer to lock up. The spectrum display of the s/w allows you to tune easily to the centre of the signal.

Brookman Spark
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Re: Digital Radio Mondial - audio codec needed

Post by Brookman Spark » 21 Mar 2016 16:41

Looking at All India Radio's shortwave DRM timetable published in Oct 2015 and valid to the end of March 2016, about half of the slots are still "temporarily in AM mode". In addition to that, evening frequency 7550 to Europe hasn't been digital for several weeks now.

http://allindiaradio.gov.in/Oppurtuniti ... 281%29.pdf

It'll be interesting to see what mix of analogue and DRM we get from AIR in the A16 season which begins on 28 March.

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