Question / Help Crackle when recording from line in

[FIgs]

When I record audio from my line in jack, I'll hear soft pops intermittently. It happens more often when the sound is louder; when the line is silent, the pops don't happen at all. Recordings made with other software (audacity etc.) don't have the crackle. It's not clipping; the pops don't hit maximum amplitude when viewed in audacity and aren't very loud. They also don't often coincide with the loudest moments of the track, plosives etc. Recording desktop audio doesn't have this problem, though I've observed it from both the line-in and rear mic jacks. Happens at both 44.1 and 48 kHz sample rates.

Log of a short recording:
https://gist.github.com/2293ba9ede3429576c4cb71becff70c4

It's pretty distracting, so I appreciate any help you can give. In the meantime I'll try building a more recent version for myself, maybe check the default settings.

 

[FIgs]

I tried resetting to default settings, picking my audio/video capture devices, and changing nothing else, but it's the same. Also tried to build from source, but it bombed out ~5% through the make (I built ffmpeg as directed, followed instructions etc.).

 

[FIgs]

Update: I tried OBS for Windows on the same computer (dual-boot). The audio is fine, but the capture (cheap EasyCap) freezes every 10 minutes or so, so the recording's no good. That might be the drivers though. I'll try to take a closer look at building from source.

EDIT: figured out the build problem, but no dice. Bummer.