Re: [Discuss-gnuradio] Lost samples from RTL2832 dongle

[CEL]

You'll find instructions at 
https://osmocom.org/projects/sdr/wiki/rtl-sdr#rtl_tcp

On Tue, 2018-01-23 at 12:50 +0000, john cooper wrote:
> Hello Marcus, good idea, I will research how  to do this and report back. 
> Many thanks. John
> 
> On Tue, 23 Jan 2018, 12:47 Müller, Marcus (CEL), <address@hidden> wrote:
> > Ah, and: Choppy audio from low-buffer streaming applications within VMs
> > is another common issue with many VM hypervisors.
> > On Tue, 2018-01-23 at 12:44 +0000, Müller, Marcus (CEL) wrote:
> > > Hi John,
> > >
> > > my experience, indeed, is that USB passthrough support in VMs is
> > > suboptimal. So, this could very well be a virtual USB host controller
> > > problem.
> > >
> > > I'd actually recommend circumventing the issue, e.g. by running rtl_tcp
> > > on the host machine, and using the appropriate source string in the gr-
> > > osmosdr source.
> > >
> > > Best regards,
> > > Marcus
> > >
> > > On Tue, 2018-01-23 at 12:40 +0000, john cooper wrote:
> > > > Hello GNU people, some help greatly appreciated.
> > > >
> > > > I am a newbie to GNU Radio and have a lost samples problem,  lost from 
> > > > the USB 2  RF device, seemingly not in the Flowgraph signal chain.
> > > >
> > > > Although I have no hard evidence I am coming to the point of suspecting 
> > > > the problem lies with the running of GNU under Oracle VM,  hosted by 
> > > > Win 10.
> > > >
> > > > Physical RF device is a  DVB-T+DAB+FM USB dongle, with Realtek RTL2832U 
> > > > and the R820 device.
> > > >
> > > > System is GNU Radio ( latest version )  running as a guest under Oracle 
> > > > VM, hosted by Win 10 Pro on a machine with significant system resources.
> > > >
> > > > Oracle version is VM 5.2.6r
> > > >
> > > > Problem is *always* dropped samples from a DVB-T+DAB+FM USB dongle, 
> > > > tens to hundreds of lost samples.
> > > >
> > > > I have done the following :-
> > > >
> > > >     Added my name to the virtualbox users list.
> > > >
> > > >     added the Virtual Box Extension Pack 5.2.6     to allow USB 2 
> > > > support in the VM
> > > >
> > > >     Selected USB2 in the Oracle VM machine.
> > > >
> > > >     Blacklisted the RTL2338 DVB-T  driver  via   
> > > > /etc/modprobe.d/blacklist-rtl.conf    etc.
> > > >
> > > >     Tested with rtl_test with sample speeds from 2.4e6 down to 0.25 e6
> > > >
> > > >     Several Flowgraphs of various example FM broadcast receivers all 
> > > > have choppy audio, believed to be due to lost sample from the RF device 
> > > > via USB2 and not seemingly due to mismatch of audio sing sample rates.
> > > >
> > > >
> > > > Using only the RTL_SDR source block and Low Pass Filter, plus the WX 
> > > > GUI FFT Sink and the WX GUI Scope Sink, in a FlowGraph produces spikes 
> > > > in the Audio which coincide with the suggested sample losses from the 
> > > > physical dongle.
> > > >
> > > >
> > > > Under any and all tests and sample rates the result of rtl_test when 
> > > > ran in the terminal is a continual stream of lost samples.
> > > >
> > > >
> > > > Other information;
> > > >
> > > > running SDR# via the host system ( Win 10 Pro )  is faultless at 2.4e6 
> > > > sample speed and all lower speeds.
> > > >
> > > > I have also  installed Gqrx in the VM and this system stalls with the 
> > > > Terminal screen failing to enter the initial set up dialogue screen but 
> > > > does list in the terminal screen the list of parameters, then hangs.
> > > >
> > > > If anyone has input to the problem, I would be very pleased to hear 
> > > > back and offer my thanks in advance.
> > > >
> > > > John
> > > >
> > > >
> > > >     Virus-free. www.avg.com
> > > > _______________________________________________
> > > > Discuss-gnuradio mailing list
> > > > address@hidden
> > > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> > >
> > > _______________________________________________
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