Audio Noise Reduction

[ChristopherLee]

Hi Folks,

I have leeched the Video "Red Dragon". I was a bit disappointed due to the bad audio record.

There is always a disturbin noise in the audio track, i know how to seperate video from audio (tmpgenc) so what program can u recommend for gettin rid of that disturbin noise in the audio track.

I tried Goldwave with the Option "Noise Reducer - Remove Hisss Noise" but the result was very bad.

I wasn´t sure where to post this so i put it in the newbie section.

Your help in this case would be apprechiated.

thx in advance

cl

[romu]

1. Convert the audio to wav (44100 Hz 16 bit stereo) with Virtual Dub (file, save wav).
2. Open the wav with Cool Edit.
3. Zoom in and find a spot with several seconds of silence (so the ONLY thing that can be heard is the noise).
4. Highlight the area. It should be AT LEAST 4-5 seconds or so.
5. Click on Noise Reduction (look for this in one of the menus, I don't remember which).
6. On the Noise reduction dialogue, click on "Get Profile From Selection".
7. Move the bar to 100%.
8. Click OK. It will reduce the noise in the few seconds section that you highlited. The noise should be greatly reduced (it is VERY hard to get completely rid of it if it's very noticeable). If it's still unacceptable (I have done this LOTS of times, and the result is always perfect or near perfect), you can specify a strenght beyond 100% but I don't recommend it because it will then lower the overall sound quality (it will sound like a low bit rate MP3 if you apply too much noise reduction. 100% should be enough).
9. Click Undo.
10. Now select the whole wave file, click on noise reduction again, check that the bar is in 100%, and click OK. This will take quite a while.
11. That's it.

[ChristopherLee]

Do i have to apply the selection to any "silence gap" or is cool edit doin this automatically after one selection?

What is with the Part that contains both .. the voice and the noise ?

thx for your help

[romu]

Your initial selection (the one you select to "load the profile") should be a short silence gap within the movie. It should not be difficult to find. Just look at the very beginning and end of the file. The 4-6 second selection should contain only the noise (it's supposed to be silence, but because the file has noise, you will hear ONLY the noise). If the highlited selection has voices or other sounds, when you apply the noise reduction filter to the whole file, the overall sound will be affected because those other sounds like voices or whatever was there, will be interpreted as noise and thus will be diminished when you apply the filter.

Once you find a few silence seconds (again, you must hear the noise very clearly), highlight the selection, click on noise reduction, and click on "load profile from selection".

Then when you highlight the whole file to apply the filter, the profile you just loaded already contains the noise information (and only the noise), and then that noise information contained in the profile is removed from the whole file. Hence, the noise is removed.

Please note that if the noise is very pronounced, you may not be able to completely get rid of it. But this technique should GREATLY reduce it.

Let me know.

[SLK001]

All selecting the silence areas is so the LOAD PROFILE FROM SELECTION will characterize only the noise (and not any wanted audio). It assumes that this noise profile is valid over the entire clip.

Some things that I do differently from what romu recommended:
1) Convert the audio to 48000, 16 bit wave, but I use either BESWEET or HEADAC3HE to convert to wave (I only do DVD's).
2) If noise is really bad, I then convert the 16 bit audio to 32 bit (this helps eliminate the "gobbly-wobbles" in noise reduced clips).
3) Use the PREVIEW function to set the amount of noise reduction that you like.

Once you are done reducing the noise, convert back to 16 bits, then save your clip.

I use COOL EDIT 2000 with the optional AUDIO NOISE REDUCTION plugin. This does a wonderful job of reducing noise (I can apply this to a vinyl record recording and approach CD quality of the sound).

[ChristopherLee]

Thank you all for your help, Cool Edit is a great tool.

I got best results with the "Hiss Reduction" and playin around a bit with the settings since there is nearly no gap without voice (the film starts with music and is splitted on 2 discs so i don´t even have a gap at the end)

Cool Edit´s Hiss Reduction highly increased the quality of the audio track sure it´s not perfect but it´s much better now.

Thank u all

cl