Input volume, Audacity 2 under Ubuntu 12.04

I am using AUdacity 2 under (L)Ubuntu 12.04. The audio is an NVIDIA ALC988A. When I open the list of input devices, I find a huge number of them-- analog, digital, spdif, pulse, default… I am not sure which one to choose-- Some of them do not seem to record anything. When I choose analog or default line 0, 1 or 2 I do get a recording, but the
sound level is way too low (from You Tube). Amplify does not help, since it amplifies the noise as well.
Any suggestions?
I am using ALSA.

For “recording” YouTube, it is better to download rather than record. There are plug-ins available for Firefox for doing this. I use “Easy YouTube Video Downloader 6.0”.

More generally, to record sounds that are playing on your computer, if you have PulseAudio running (it is by default in Ubuntu) then the easiest method is to install “PulseAudio Volume Control” (pavucontrol) and use it to set the recording input to “Monitor”.
See here: