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 > > [email protected] > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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