[MPlayer-users] How to suppress background noise

[Alain Barthélemy]

Le jeudi 23 octobre 2003, 14:03:26 ou environ Sycotic Smith <sycotic at linuxmail.org> a écrit:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> > [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> > 
> > Am Donnerstag, 23. Oktober 2003 20:57 schrieb Alain Barthélemy:
> > 
> > > Pinnacle PCTV card BT878 chipset
> > >
> > > After capturing the image is very good but I have an horrific
> > > background noise. I don't have such a loudly noise if I listen
> > > directly to the video cassette or TV with KwinTV.
> > >
> > > Where could the problem be? The PCTV card has already been used before
> > > without that problem (not with mplayer/mencoder).
> > 
> > Maybe that other software had a denoise filter or you just had a higher 
> > compression ratio.
> > 
> > You coult change the video cable (you use s-video?), close the case of 
> > your PC, replace your BT878 against a modern low-noise card,...
> > 
> > 
> > > Is there some filter with mencoder to eliminate some high-frequencies
> > > sound or some Dolby-like filter?
> > 
> > You could read "man mplayer" (http://www.MPlayerHQ.hu/DOCS/en/
> > documentation.html doesn't contain info about video filters) and the 
> > output of "mplayer -vf help" and "mplayer -pphelp".
> > 
> 
> You missed his question entirely. This is actually SOUND not VIDEO related. Unfortunately, I don't have the answer either, though. Maybe he *did* RTFM and only found *video* filters, and no *sound* filters... I say the problem is a faulty cable or driver for the sound on the tv card.

> 
> Suggestion: Does the same background noise come through if you use mplayer to play the stream instead of mencoder? If so, the problem would likely be cord, hardware or driver related.

Thanks. I thought of playing directly the stream with mplayer but
stupid question: HOW? I have a lot of howto's, e-mails, etc mainly
about mencoder. I can play DVD's.

Thus

mplayer -tv drivers=v4l:width=640:height=480 tv:// ===> screen??

People don't usually watch TV with mplayer (me neither) so not very
much literature on the mailing-list.

I don't have much background noise with KwinTV though. It seems thus
that this background noise is amplified during encoding. It is a pity
we can not see the image and sound while encoding to check if
everything is OK.

Sorry for stupid question. 

> 
> > > Or could I change something in the
> > > code line above to correct that problem.
> > 
> > > Thank you for any suggestion.
> > > mencoder -tv driver=v41:width=640:height=480
> > 
> > Is your video interlaced (and you want to deinterlace it)? Than you should 
> > use full width and height.
> 
> Maybe he wants it this size due to disk space? Not everyone wants the same output size as input. Or maybe he doesn't have the CPU to handle full w/h... To each their own...
> 
> > > tv:// -vf eq=10:5 -o test.avi -endpos xx:xx:xx
> > 
> > Why -vf eq=10:5?
> > "-tv 
> > driver=v4l:width=[...]:brightness=5:contrast=0:saturation=20:volume=40" 
> > exists.

Why -vf eq=10:57

Because when I first tried driver=v4l:width=[...] ....  did not work
and I spent one full day trying to find how to brighten my image.

> 
> Again, to each their own. There seems to be duplication of filters between -vf and -tv if this works both ways. Funny, if both work the same (assuming they do, I can't test), why prefer one over the other?
>  
> > If you want to _see_ what effects Mplayer's video filter produce, see 
> > http://home.knuut.de/MWieser_/
> > 
> >                 Matthias
> 
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-- 
Alain Barthélemy
cassandre at bartydeux.be
http://bartydeux.be
Linux User #315631