Unwanted Audio Gain-Compression

cakefoo · Post by **cakefoo** » Thu Apr 20, 2006 1:38 pm

I recently made a music video montage of sorts, and noticed, after watching
the final output copy, I could detect signs of audio gain-compression.
At first, I thought the original source music was like that- but upon listening,
the source music was absolutely not identical- especially noticeable during
the louder parts in the song. The rock guitar, bass drum, and snare were
drowning out the cymbals.

To shed any doubt, I tried to run the song through as an uncompressed
PCM format (mp3 format was used for the first attempt) and it still got
gain-compressed.

Is there a solution to disable that? Perhaps a registry edit?

Thanks for looking!

DVDDoug · Post by **DVDDoug** » Thu Apr 20, 2006 5:31 pm

I've noticed something similar... I noticed some sort of "overloading distortion" when converting from MPEG-2 audio to AC3. It could be the same problem, or the same cause... Clipping / overloading / limiting is a kind of compression. (I don't recall having the same issue when converting from PCM (WAV) to AC3.) I solved it by adjusting the volume down to 75%.

I don't understand how this is happening with a digital-to-digital conversion... And, I have no idea if 75% is the "right" amount of adjustment...

cakefoo · Post by **cakefoo** » Thu Apr 20, 2006 5:39 pm

That's working, Doug, thanks

It was little more like 62-70% though,

cakefoo · Post by **cakefoo** » Thu Apr 20, 2006 5:51 pm

It was impossible doing keyword searches for "audio compression" on google
search and individual forums even, because of the double meanings, most
commonly referring to compression codecs like mp3. gain limiter, gain limit
gain limiting unwanted undesirable

I'm just posting these tagwords for people if they're out there desperately
googling for the same question

sjj1805 · Post by **sjj1805** » Thu Apr 20, 2006 5:58 pm

A few possible solutions:

1. Check the windows Volume control.
goto Options | adjust volume control for recording
(Default is for playback) then check that it isn't recording at too high a level.
2. Export the sound track as a sound file in WAV format.
Open the WAV file with audacity (See free stuff: http://phpbb.ulead.com.tw/EN/viewtopic.php?t=12931) then use the "Normalise" filter.
3. Save the modified sound file.
4. Replace the sound file in VideoStudio with the modified one.

cakefoo · Post by **cakefoo** » Thu Apr 20, 2006 7:08 pm

sjj1805 wrote:A few possible solutions:

1. Check the windows Volume control.
goto Options | adjust volume control for recording
(Default is for playback) then check that it isn't recording at too high a level.
2. Export the sound track as a sound file in WAV format.
Open the WAV file with audacity (See free stuff: http://phpbb.ulead.com.tw/EN/viewtopic.php?t=12931) then use the "Normalise" filter.
3. Save the modified sound file.
4. Replace the sound file in VideoStudio with the modified one.

Normalizing- isn't that where loud portions are tamed and quieter portions
are amplified? Because (a) I don't want to compromise the original song's
quality, and (b) I don't want to have to run everything through another
program because it's more time consuming- (c) Doug already got it right-
Thanks though, ssj.