[Interest] I am having problems reading multichannel data from usb soundboards using QAudioInput and QAudioInfo
val and leslie
vveirs at coloradocollege.edu
Thu Aug 15 22:08:12 CEST 2013
Greetings,
I am brand new to this mailing list so bear with me as I learn how you
operate.
I have found that the Audio Input example that comes with QT 5.0.1
running under Ubuntu 12.03 and 13.04 does not return correct
multichannel data. I modified the example for two channels and I find
that data from channel 1 shows up in channel 1 and also in channel 2. I
have checked this with two different USB soundboards (Griffen iMic and
Lexicon Omega). I also have checked that the Ubuntu ALSA driver works
for the USB soundboard (arecord -v -c 2 -f cd -t wav -D hw:CARD=system
test1.wav records a proper two channel file with the proper channel
separation).
So, it seems to me that AudioInput or AudioInfo is not working properly.
If I interrogate the devices via
AudioInfo via foreach(const QAudioDeviceInfo &deviceInfo,
QAudioDeviceInfo::availableDevices(QAudio::AudioInput))
qDebug() << “Device name: “ << deviceInfo.deviceName();
I find that the iMic shows up only as mono:
Device name:
“alsa_input.usb-Griffin_Technology__Inc_iMic_USB_audio_system-00-system.analog-mono”
Interestingly, the Lexicon which is a 4 channel A/D shows up as stereo
Device name:
“alsa_input.usb-Lexicon_Lexicon_Omega_Lex1.00-00-Omega.analog-stereo”
When reading 4 channel data with a signal in channel 1 and zero signal
on the other channels, the signal comes in on channel 1 but various
seemingly random portions show up in the other channels.
I wonder if others have found a solution to getting multichannel audio
data into Qt using QAudioInput?
Thanks for any suggestions.
Val
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