Normalizing Clipped Audio

KevinLeeC wrote on 12/2/2005, 8:58 AM

I'm working with a chunk of video which has a pretty quiet audio track. I would like to normalize it so that it will be in the same range as the rest of the project.

The trouble is that it has one point during which the audio got clipped. So the normalize isn't really sufficient to raise the level of the audio.

Is there some way to tell the normalize to ignore the clipped portion?

KC

Comments

jtfrazer wrote on 12/2/2005, 9:33 AM

KC,

You could put an audio envelope in the track in question. You could lower the volume at the point where the clip is and increase the volume everywhere else. Highlight the audio track in question, then click "Insert" on the main menu. You'll see where you can add an audio envelope. Use the "Volume" type. You'll get a blue (at least on my system) line in the audio track. Double click on the line to insert nodes. You can then raise and lower volume at the node points.

Jim

KevinLeeC wrote on 12/2/2005, 9:42 AM

I tried that, but the envelope seems to be applied across the entire length of the voice track -- not just on the specitic clip I'm struggling with.

Tim L wrote on 12/2/2005, 1:43 PM

You can add nodes to the volume envelope, to break it into sections that can be adjusted individually.

Just in front of the clip you want to change, double-click on the blue audio envelope line and it will add a little square (I think). Do the same thing just to the right of the first node (add a second). Now go down to the end of the clip, and add two more.

Here's a cheap ASCII simulation (I hope it works)...

[normal clip....] [quiet clip..............................] [normal clip.....]

-------------------+-+--------------------------------+-+------------------

Now, grab the line in the center of your quiet clip (don't double-click) and just drag it up to raise the volume here. That whole line segment will move up, and the sections between the closely-spaced nodes will angle up.

[normal clip....] [quiet clip..............................] [normal clip.....]
...........................+--------------------------------+...........................
.......................... | ............................................ | .........................
-------------------+ ............................................ +------------------

(okay, it didn't work so well. This forum software/html ignores multiple consecutive blanks in a row, so I had to fill in with periods)

You can grab and drag any of the nodes directly (even left and right), or grab and drag a segment in between nodes. You can also zoom in close on an audio track and do this sort of thing to reduce volumes where necessary, to get rid of a cough, or camera handling noise, or clunks or thuds or whatever.

Tim L

KevinLeeC wrote on 12/2/2005, 2:26 PM

Thanks, Tim. I'll give that a try.

KC

KevinLeeC wrote on 12/2/2005, 2:40 PM

Ah-ha! Fiddling with the envelope didn't work as well as I hoped. However, when I tried applying some non-realtime audio effects, I realized that Vegas was actually building separate .wav files. I took one of those into an audio editor and played with it until I had the sound I wanted. Then told Vegas to use that take. Worked perfectly.

KC