Input Device dropdown list doesn't make sense

Audacity 3 Help Forum GNU/Linux
1

Hello
I am new to Ubuntu, running 12.04.
Audacity installed from repository, I think, I definitely didn’t compile it myself from source code.
I have Pulse Audio and I have Audacity set up to record streaming audio from the pc OK.
I recently got Skype to work from the mic by disabling glitch free audio.
I have a MSI motherboard purchased 5 years ago and dual core processor and on board soundcard, the software drivers were Realtek in Windows but don’t know if any of the hardware is Realtek but the following description of all inputs presented by the drop down list in Audacity may give a clue:

I don’t know if it is relevant as I have pulse audio to record from the pc and don’t seem to be able to control that from within Audacity:

Audacity record options: (the Audio Host box contains ALSA)
Mic icon shows a drop down list of 30 different inputs, 5 groups of 6 inputs each
First group:
HD VIA VT82xx: ALC 883 Analog (hw:0,0):
Inputs: Rear Mic : 0 , Front Mic 0, Line 0, then Rear Mic 1, Front Mic 1, Line 1.
2nd group:
HD VIA VT82xx: ALC 883 Analog (hw:0,2), same 6 inputs
3rd group sysdefault, same 6, 4th group pulse, same 6, 5th group default, same 6.

I couldn’t do a screenshot , for some reason dropdown lists seem to disable screenshots, so had to type it out manually like this.

I can record from mic with HDVIA VT82xx etc, hw0,0, Rear Mic 0.
Usually also from Groups 2 and 3, Rear mic 0.
But not from Pulse group, and after recording blank from Pulse group then some of the other input selctions that did work, cease to work.
Then after recording from HDVIA VT82xx etc, hw0,0, Rear Mic 0, some of the other inputs, that didn’t work, start to work again.

Also, changing the input causes the recording level to change.

Can anyone explain what is happening here? Which input SHOULD I use?
If I have pulse installed, why doesn’t it record from mic?
What are the different groups?
why is there rear, front and line 1, and then rear, front and line 2? (BTW skype only worked with mic in rear socket)
Why is there ALC 883 0,0 and 0,2?
Why is there default and also sysdefault?

When I want to switch back to recording from inside the pc I select anything from the pulse audio group and "alsa plugin {audacity} alsa capture from (in box) “monitor of VT 8237A 8251HDA controller analogue stereo” " appears in the recording tab of pulse audio control aslong as I am actually recording something.
But sometimes “default” works too. It seems to depend on what was selected before.

What does “monitor of” mean, when that is written before the device name? Is it important?

If I knew the answers to some of the above list of questions, some of this would make more sense

2

Sorry you received no reply yet, but there are many questions packed in there.

Although I have Ubuntu 12.04 for testing I am not a Linux expert (in fact on that version of Ubuntu, audio does not always do what it is supposed to for me). So I am only starting the ball rolling in a cursory fashion.

Do you mean this:
pulseaudio - Skype and VLC sounds sizzling, distorted, bad, crackling - Ask Ubuntu ?

Aside from whatever problems there may be with pulse, Skype could cause unpredictable behaviours itself.

Generally it may be better to use the (hw 0:x) inputs because those should give direct access to the hardware. Pulse will add latency, but may resolve any resampling problems that occur. The Audacity input and output sliders should adjust the respective sliders in ALSAmixer.

“hw:0,0” should mean the first digital audio device on the first sound card. “hw:0,2” should mean the third digital audio device on the first sound card. What does ~/.asoundrc contain and what does aplay -l (l as in label) produce?

“Default” (I think) just does the same as selecting “pulse” where pulse is enabled. That is just a guess based on my 12.04 and 12.10 systems.

“Sysdefault” ought (in principle) I think to select whatever is the selected device in ALSAmixer, but it does not do that consistently for me on 12.04.

When you select “pulse” the input should (I think) be the one you chose in pavucontrol (Pulse Audio Volume Control).

Changing the input from mic to line should change the input level if they are different.

If ALSAmixer and pavucontrol don’t agree about the level of the same input (their sliders for that input are not linked) then changing from hw to pulse probably will change the input level. The mic sliders for pavucontrol and ALSAmixer are not linked on my Ubuntu 12.04 system.

(As I understand it) when Audacity (or other applications) monitor or record, they create an ALSA plug-in capture device. Pulseaudio sees that device and can make it record from the monitor of the current playback device (for recording computer playback) or from the current recording device (Built in Audio Analog Stereo).



Gale

3

Hi and thanks

Yes, I do mean that exact page linked to. The page described exactly the problem I had and disabling glitch-free seems to have completely solved the Skype and audio stream problems.

After making a Skype test call and listening to a stream with VLC media the current settings in the pavu tabs are :
Playback tab:
System Sounds: Mono
ALSA plug-in {Firefox} ALSA Playback
VLC Media Player: Audio Stream
Recording:
Blank
Output devices:
VT8237A/VT8251 HDA controller Analogue Stereo
Input:
VT8237A/VT8251 HDA controller Analogue Stereo
Port:Rear Mic selected. (Front mic isn’t detected on my pc in Ubuntu or Windows, I never found out why) the volume has been adjusted lower than the default 0dB level, maybe by skype.
Config:
VT8237A/VT8251 HDA
Profile
Analogue Stereo Duplex selected

Without changing anything manually, Audacity will record this stream, and the settings on Audacity are Host ALSA , Output Default, input Pulse Front mic 1, or any Pulse input. Also any default input, as you suggest.

So with these settings I can get everything basically working

But I cannot change the recording level in Audacity, I have to have the pavu control window open and do it from the recording tab there. Could this be fixed?

Recording from Mic or Line input works as follows:

hw:0.0 0 Yes, with level adjustment within Audacity
hw:0.0 1 Yes but no level adjustment
hw:0,2 0 Yes, but no level adjustment
hw:0,2 1 Yes, with level adjustment
Sysdefault 0 Yes with adjustment
Sysdefault 1 yes, no adjustment

All other inputs, won’t record.

Quote ″ “hw:0,0” should mean the first digital audio device on the first sound card. “hw:0,2” should mean the third digital audio device on the first sound card″

Could you explain this a bit more? Why would there be more than one device ?

~/.asoundrc
bash: /home/ben/.asoundrc: No such file or directory

aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: VT82xx [HDA VIA VT82xx], device 0: ALC883 Analog [ALC883 Analog]
Subdevices: 0/1
Subdevice #0: subdevice #0
card 0: VT82xx [HDA VIA VT82xx], device 1: ALC883 Digital [ALC883 Digital]
Subdevices: 1/1
Subdevice #0: subdevice #0

Quote ″ When you select “pulse” the input should (I think) be the one you chose in pavu control (Pulse Audio Volume Control). ″

When I select Pulse the only choice presented in the Pulse Input tab is Port, choice of line in, front or rear mic, which isn’t relevant, because I am using none of these, I am just selecting any pulse input to get the Pulse to work for recording from within the pc.

Quote ″If ALSAmixer and pavucontrol don’t agree about the level of the same input (their sliders for that input are not linked) then changing from hw to pulse probably will change the input level. The mic sliders for pavucontrol and ALSAmixer are not linked on my Ubuntu 12.04 system.″

I am lost here, but in any case I have to use hw for mic and line input, and Pulse for pc input. I can’t interchange them. Did I miss something?!

Tthanks for answering, pointing out that hw stands for hardware and things like that is just the kind of detail I need!
My main priority now is to be able to adjust level from within Audacity, but when I boot in to Windows, the Realtek software has to be opened as I can’t adjust from Audacity there either.