[MPlayer-users] Re: How to suppress background noise

[Stefan Seyfried]

Alain <cassandre at bartydeux.be> writes:

> I can hear the sound during capture (Volume-In on PC) and it sounds OK
> but if I do:

this is direct loopback from line in -> mixer -> line out on the
sound card. The hum probably is from a ground loop. Disconnect all
antenna cables from the VCR, only leave the power and the a/v cable
and the hum will be gone, i'm sure.
 
> mplayer test.avi
> 
> It is no more a hum I have but a distorted sound.
> 
> I don't understand because there is now a direct connection (via
> amplifier) between Video-recorder and PC Line-In (not Microphone-In!).
> 
> With the same arrangement I can easily capture my Radio sound Output
> and convert it to .mp3 without distortion. The only difference is the
> Sound source (and combination with Video analog signal with mencoder).

What is your radio source? Probably it has a lover voltage than your
VCR.
Try adjusting the igain on your soundcard, this is, where the recording
level is set, the "line1" slider is for the playback/loop-through-level.

I always use the "record"-tool (comes as part of the xawtv package on
SuSE), it has a nice vu-meter in the console and "aumix" to set the mixer.

Also note that there are soundcards (crap like my soundblaster pci128),
which cannot do full 16bit but start to distort heavily if the vu level
is over ~50%. Fortunately record shows the signal level in numbers, so
i just adjust igain so the vu never is > 15000.

Good luck.

Stefan
-- 
 Stefan Seyfried, seife at gmane0305.slipkontur.de
+----------------------------------------------+

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