mrraspberrypi
Posts: 10
Joined: Tue Sep 25, 2012 2:37 am

Re: Record USB audio input

Tue Oct 30, 2012 9:07 pm

You mean the new kernel has been already released and has the usb fix??

44922035
Posts: 9
Joined: Fri Nov 16, 2012 6:34 am

Re: Record USB audio input

Sat Nov 24, 2012 12:13 am

So the LogiLink sound card works for recording?

I have tried a few others with nothing but frustration.

Was there any custom stuff that had to be done to get it to work? (mods to asound.conf or ~..asoundrc)

lfchords
Posts: 13
Joined: Thu Mar 21, 2013 2:28 am

Re: Record USB audio input

Mon Apr 08, 2013 12:45 am

Hi there

I'm also having issues, but with a Cmedia USB card, and noise, which sounds like this:

https://docs.google.com/file/d/0B4zhzWw ... sp=sharing

More details here :
http://www.raspberrypi.org/phpBB3/viewt ... 75#p326675

if anyone has any leads, it would be greatly appreciated...
thanks
-s

lfchords
Posts: 13
Joined: Thu Mar 21, 2013 2:28 am

Re: Record USB audio input

Thu Apr 11, 2013 5:26 am

I also found the root of the issue, though it seems to be a combination of things.

Downgrading to 1.1 helped, as did using this ALSA config that I found on another posting :

Code: Select all

pcm.!default {
              type asym
              playback.pcm "defaultplayback"
              capture.pcm "defaultrec"
                hint{   show on
                   description "default play and rec koko"
                }
      }

      pcm.defaultrec {
              type plug
              slave {
                  pcm "hw:0,0"
                  rate 48000 
                  channels 2
                  format S16_LE
              }
                hint{   show on
                   description "default rec koko"
                }

      }

  pcm.defaultplayback{
          type rate
          slave.pcm mix1
          slave.rate 48000 

          #Intel(R) Core(TM)2 Duo CPU     E7500  @ 2.93GHz:

            #converter "samplerate_best"     # perfect: 16%cpu, maybe overkill
            #converter "samplerate_medium"   # almost perfect: 6%cpu
            #converter "samplerate"          # good: 4%cpu, definitely usable
            #converter "samplerate_linear"   # bad: 2%cpu, way better than default wine resampler
            #converter "samplerate_order"    # very bad: 2%cpu, like the default wine resampler

          converter "samplerate"

            hint{   show on
                   description "default play koko"
            }
  }

    pcm.mix1 {
            type dmix
            ipc_key 1024
            slave {
                pcm "hw:0,0"
                rate 48000
                periods 128
                period_time 0
                period_size 1024 # must be power of 2
                buffer_size 65536

            }     }

Also, when I got it working, I realized the buffer settings were important..
I got different results between these 2 :

arecord -vv -f S16_LE -c 1 -r 44100 --buffer-size=128000 -D plughw:0,0 t15.wav
arecord -vv -f S16_LE -c 1 -r 8000 --buffer-size=5000 -D plughw:0,0 t52.wav

the buffer sizes on the first mean almost no pops/stuttering, but the audio gets cut off early, I guess the buffer is dropped. I plan on doing voice recordings, (like a radio) so dropping to 8khz actually fits the sound I'm going for, and I'll keep the lower buffer ... keep this mind while experimenting.

I did notice though when I tried to backpower from my hub, I started getting stuttering/pops, no matter which setting.. so it appears for me to get clean recordings I need to power my Pi with an adapter to mains, and the hub needs it's own adapter...

Also if anyone is thinking of doing mp3 encoding, def look into this: https://github.com/savonet/shine
another user here posted about it, and you have to compile it but well worth it cause it flies compared to Lame encoding...
-s

akopac
Posts: 13
Joined: Sun Oct 19, 2014 7:58 pm

Re: USB audio input

Mon Dec 28, 2015 12:33 am

TJ Shickley wrote:I hope we can get this worked out. I'm a Linux noob but an amateur radio operator. I want to interface my RPi to my transceiver for digital transmission modes and CW. This is an interesting thread for this. TJ Shickley AKA KB3VLW also on gmail.
Hi TJ

I'm a ham operator with a RPI2 (running Jessie) and want to use it with a usb sound adapter. Did you find one that will recieve (mic jack) well yet.

paulie
Posts: 260
Joined: Thu Jan 19, 2012 6:51 pm

Re: Record USB audio input

Thu Mar 24, 2016 10:10 pm

I'm using a GeneralPlus USB soundcard to input audio ax25 tones to Xastir, for APRS.

Rather than use soundmodem, I am using direwolf, which has the advantage of allowing PTT control via a GPIO pin.
Currently, receive works: I have yet to wire up a GPIO pin and feed audio output to the rig.
It has been my custom to use Xeyes

openhsc
Posts: 2
Joined: Tue Feb 12, 2019 8:25 pm

Re: Record USB audio input

Tue Feb 12, 2019 8:49 pm

mahjongg wrote:
Fri Aug 24, 2012 12:48 am
perhaps an isolation transformer before the input will help, or perhaps grounding the PI, normally the only ground path the PI gets is when its grounded through a HDMI monitor and the HDMI cable.
With an ungrounded PI there will be all kind of high voltage noises on the GND of the PI, which may cause unwanted audio currents into the audio input, if grounds are not galvanically isolated (with an audio transformer).
Grounding (or the lack thereof) is likely to be the root cause. See also https://www.raspberrypi.org/forums/view ... p?t=150722

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