Problems with ambient noise in video

Question

Hi,
I've been having problems with this weird noise. See, I went to an event a few weeks ago and I took one clip of an actor and recorded it on my Panasonic DMC-TZ5 camera and transferred the footage to iMovie. It seemed fine to me but when it reaches 2 minutes there's this noise that blocks out the actor talking and then seems to fade more into the background at over 3 minutes and you can hear him again for the rest of the video. Is there any way I can eliminate this noise problem and if so, what application should I use? I tried to "normalize clip volume" when opening up iMovie but that didn't really do anything. I've heard of Soundbooth and other audio aps but I have never used them before so I have no clue where to start.
I have uploaded the video on YouTube:
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/7f5ewdeGwVo&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/7f5ewdeGwVo&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>
...And nothing is more irritating to receive comments from others who complain that the sound is horrible. Any suggestions?
Thanks in advance!

Answer 1

You shouldn't have used 'Normalize' with video like this, which has a very low speech volume (..the mic seems to have been pointed towards the audience, not the actor).
'Normalize' brings everything up to a constant, "solid" volume level. So if a voice is quiet, all the background hiss is brought up to a higher volume along with the quiet voice itself. Where a speaker pauses, and the voice is absent, the background hiss and noise may become even LOUDER to bring everything up to a standard high volume level!
So if it's not too late - but I suspect it is! - you should really Undo the 'Normalize' setting ..but once things are Saved it's probably impossible to Undo that.
The noise which starts at 2mins and runs to 3mins may be some artifact produced by the software which did the Normalization ..I don't know for sure. It's a weird "artificial" sound, rather similar to repeated "out-of-phase" abnormalities, and has many characteristics of having been created by sound-manipulation software.
Because that extra noise is not completely solid, regular and constant (..like a solid constant hum, or a constant buzz..) it would be very difficult to remove it ..and removing it would remove virtually all of the actor's voice, because the weird noise is so much louder than the actor's voice.
Programs like 'SoundSoap' (..click on that blue link for info..) promise to "remove noise" ..but they can only remove regular, constant, single-frequency noise well.
Even 'SoundSoap Pro' wouldn't be able to remove that noise and leave the actor's voice behind, as so many of the frequencies (..highs and lows..) of that noise coincide with his, and others', speech frequencies.
So you'd end up - if you did try removing the noise - with an extremely faint and "thin" sounding voice, which came and went, pretty much disappearing into some background hiss, and it would sound as if it were heard coming out of a water pipe.
If you can go back to your original camcorder recording (..before 'Normalization'..) I suggest chopping out that one minute which has the "noisy" material (..if it really was there on the original). Then use the free 'Audacity' program..
(..click on that pic, above, for a larger, clearer image..)
..to remove the background hiss and to boost mid-range sounds, then the actor's voice would come out much clearer, and you could also increase the overall volume, too - but without 'Normalizing' it until you'd first removed as much background hiss as possible, and had boosted his mid-range voice to greater prominence.