[op25-dev] Re: No audio

Tom Hayward tom@tomh.us [op25-dev] op25-dev at yahoogroups.com
Tue Oct 17 21:47:22 UTC 2017

On Tue, Oct 17, 2017 at 2:34 PM, gnorbury at bondcar.com [op25-dev]
<op25-dev at yahoogroups.com> wrote:
> More command line options are needed:
>   -O Loopback:0,0 -V -2 -U

Thanks, I must have missed that detail with the conversion to rx.py. I
already have -2, but not -V and -U.

This fixed it. I'm getting audio through the loopback now!

> Make sure you see an entry in the log file that says "audio device: Loopback:0,0" or whatever alsa device you are using.

I don't see this line in the output. I also haven't specified a log
file. Is there a default log path? Is this something I should expect
to see in stdout or stderr?

> In reality you're probably better off making sure op25 plays audio through the default device before you worry about getting it going through the loopback.

I tried that, but virt-manager isn't even passing the speaker test
audio, so I think that's a lost cause. There is no physical sound
output on this system.

> As a secondary recommendation, the alsa buffering is considerably better in the version of sockaudio.py found in my github repo.  I suggest you upgrade to that version as it has other fixes too.

It's unclear to me what sockaudio.py does and how I would use it with
darkice. Is there an example of this somewhere?

I tried your repo, but got an error, so I went back to max:

tom at stream:~/op25/op25/gr-op25_repeater/apps$ git status
HEAD detached at boatbod/master
Untracked files:
  (use "git add <file>..." to include in what will be committed)


nothing added to commit but untracked files present (use "git add" to track)
tom at stream:~/op25/op25/gr-op25_repeater/apps$ ./rx.py --args rtl=0 -N
LNA:42 -f 774081250 -S 1320000 -v 5 -2   -T ss911_tacoma.tsv
linux; GNU C++ version 4.8.2; Boost_105400; UHD_003.005.005-0-unknown

gr-osmosdr 0.1.1 (0.1.1) gnuradio
built-in source types: file osmosdr fcd rtl rtl_tcp uhd hackrf bladerf rfspace
Using device #0 Realtek RTL2838UHIDIR SN: 00000001
Found Rafael Micro R820T tuner
gain: name: LNA range: start 0 stop 0 step 0
setting gain LNA to 42
supported sample rates 250000-2560000 step 24000
Exact sample rate is: 1320000.047207 Hz
set_center_freq: 774081250
Using Volk machine: sse4_2_64_orc
Traceback (most recent call last):
  File "./rx.py", line 671, in <module>
    tb = p25_rx_block()
  File "./rx.py", line 220, in __init__
  File "./rx.py", line 606, in open_usrp
  File "./rx.py", line 542, in __set_rx_from_osmosdr
    self.__build_graph(self.src, capture_rate)
  File "./rx.py", line 283, in __build_graph
    symbol_rate = self.symbol_rate)
  File "/home/tom/op25/op25/gr-op25_repeater/apps/p25_demodulator.py",
line 173, in __init__
    self.lpf = filter.fft_filter_ccf(decimation, lpf_coeffs)
AttributeError: 'module' object has no attribute 'fft_filter_ccf'

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