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View Full Version : Audio Level Edit To Smpl Standard For Vcd Music



Asspin
04-29-2006, 02:47 AM
This was originally done to help someone I know. I thought of posting it here so the info might also help others...

First to examine the audio levels on the final video I took it into Virtual Dub and did a "save wav"
This produces a wav file that is a good interpretation of the audio part of the file captured. I took that wav file and opened it in Cool Edit. Every Audio capture device/machine/source(COAX,RCA) records audio differently. When editing audio to go onto a video, you must compensate for anything that is noticably "off."

If you see the TOP "left channel" you notice the level is considerably lower than the bottom or "right channel"
http://www.videopimp.org/images/cooledit.gif

To compensate for this first you should highlight the lower channel and amplify it to match the other. You just have to eyeball it sometimes. In this case, I decided to amplify it 150%
http://www.videopimp.org/images/cooledit0.gif

Now you can see that both channels appear to be even. Now we look at the audio as a whole and check to see if the mean or average more or less is at the 30,000db smpl mark. To make it get to that level, I selected both channels this time and amplified them together by 115%
http://www.videopimp.org/images/cooledit1.gif

This is what you should end up with. You can also use noise reduction features and hiss reduction but NEVER normalize audio (unless its from a horrible sounding bootleg.) What normalizing will do is make the entire sound level(like a long smooth rectangle with no peaks.) That is not how music is intended to be heard. Check some CD audio from any song and you will notice how it is not normalized as some parts of some songs are intended to be heard at higher decibal levels.
http://www.videopimp.org/images/cooledit2.gif

hope this helps anyone struggling with audio on these vids. If you are using Cool Edit and it is not showing you 2 channels, click the small button at the top left corner.

Here is another example of a different song captured from live TV. As you can see these levels will vary depending on Hardware and Source.


Original Audio from video(notice left channel again is lower than your right)
http://www.videopimp.org/images/strokesCE1.gif

Audio after amplifying channels to match then amplifying 275% overall to get to smpl, then applying Standard Hiss filter and fading audio.
http://www.videopimp.org/images/strokesCE2.gif

This post was pulled from old forums