remove audio noise

[loulou]

I tryed to read the guides and search the forum, but I wasn't able to find what I look for.
So, sorry if my question has been worked through already, it's just that I couldn't see it.


Here is my problem:
I'm encoding from DVD to avi. The DVDs are recorded from tv, and the audio has a bad continuous noise like "brrr brrr" or "prrr prrr".
In some points the noise is very loud.

I'd like to get rid of the noise in the avi files (I'm not keeping the DVDs).

My encoding path is: import DVD to HD, biuld a DGIndex project demuxing audio, make an avisynth script, encode using Virtual Dub Mod (Xvid for images, and lame to mp3 cbr 128 for audio)

There's three ways I can follow:
1) Denoise audio in the avisynth script (is it possible? are there any plug ins?), before the virtual Dub step.
2) Denoise audio in Virtual Dub Mod (though, the additional filters that are built in seem to not work. I tryed a lowpass: if I let it set to 4000 it modifies voices and musics, if I set it to 6000 it doesn't get rid of the noise - Hence, are there any external audio denoising additional filters to use in VDub?)
3) Denoise the audio after I encoded with Virtual Dub, hence when I have a mp3 128 cbr stream.

What do you advice and how to?

Thanks for any help, I really appreciate :)

[setarip_old]

Hi!

Click on the following link and read posts #17 and #18:

http://forum.doom9.org/showthread.php?p=968382#post968382

[Mug Funky]

sounds like video signal's coming into your audio.

you're out of luck removing that stuff :devil: , but you can calm it down a little with a click/pop filter. try pull the audio out and use audition or a similar program. i'm not sure if audacity (free) does click/pop though. you'll have to use quite heavy settings on it too.

it also might benefit from a notch filter set to the pilot tone of your TV (PAL = 15625 Hz, NTSC = 15734 or 15750 for black and white). this may not be audible, but it'll affect compression later on and waste bits if it's there (which it most likely is).

never process audio after compression, btw - so don't do the NR after going through virtualdub.