How to Normalize AVI Video Files

Many times when I made a DVD from an AVI file and played it on my TV, I had to turn the TV volume up almost to maximum to hear the actors. Then when the action switched, the TV turned off and almost made me deaf, so I had to turn the volume down. Of course, for quiet scenes I had to turn up the volume again. It started to get very boring. I figured there must be a way to normalize the AVI and have the volume level at typical TV volumes so that you don’t have to constantly turn the volume up and down depending on the part of the movie. that I was watching.

I had similar issues with my mp3 music files but was able to equalize them so that they all played at the same volume when playing the CD in my car or sound system. The volume of an AVI file cannot be treated the same as mp3 music, because the AVI has a much wider range of sounds. AVI sound can range from very low to very high where the mp3 volume tends to be at a more constant level.

To see if I could do something similar, I performed an experiment with an AVI file, which when I created a DVD had this very low volume causing the TV volume to constantly increase and decrease.

Here is the software I used.

1) Audiograbber 1.83 by Jackie Franck

2) MP3gain by SourceForge

3) Normalize -0.253 by manual Kasper

4) Pers-o-FrontEnd 4 Normalize the GUI to Normalize-0.253

5) Pazera audio extractor

6) AVIcodec

All of the above software are free to download. Just google and find. The first thing to do is find out what kind of audio file is in the AVI. We do this by running the AVIcodec program. We select the AVI in question then click on it in the program to see its characteristics.

In an AVI, the audio is usually in mp3 format and can be one of the following:

1) 128 kbs bit rate, 44,100 Hz sample rate and 2-stereo channels, or

2) 128 kbs bit rate, 48000 hz sample rate and 2-stereo channels

The first thing we do is extract the audio file from AVI using Pazera. We extract an audio file as a PCM wav file. We then extract the audio file again, but as an mp3 file. The mp3 file is usually the audio encoded in the vedio AVI file. If the mp3 file is sampled at 48000hz, you need to extract it at 44100hz first, as this is how audiograbber expects the wav file to be.

We rename the files as:

1) TestPCM.wav for PCM file

2) TestMP3.mp3 for mp3 file

We now open Audiograbber and enter the normalization window. We enter the 44100hz PCM wav TestPCM.wav, then press the test button to see its maximum and average value (volume).

Here are the results:

Peak value: 77.77

Average value: 13.68

By mp3 volume standards, the average would be considered extremely low. We now open the MP3gain program and enter the TestMP3.mp3 mp3 file and perform a track analysis which yielded:

Volume: 82.6

As this has been converted to DVD, then it appears that if the ripped audio file in mp3 format has a volume of 82.6, it can be considered too low for normal DVD conversion.

We now run the Pers-o-frontend GUI and enter the TestPCM.wav 44100 Hz file. We use the -m parameter to 100% to set all audio peaks to 100%. To get 100%, the program indicated that it should use a gain factor of 2.184 dB

We now use audiograbber and input the modified -m TestPCM.wav and do a test which gave the following:

Peaks: 100

Average: 17.58

We see that even with the audio peaks all set to 100%, the volume was still low. I have found that applying a gain of around 12 db always seemed to give good volume levels. Since the -m option applied about 2 dB of gain, then applying a 10 dB gain to the modified TestPCM.wav would suffice to increase its overall volume. We run the Pers-o-frontend GUI and reenter the modified TestPCM wav -m. This time, however, we choose the -a option at 10 db. Now we run Audiograbber again and this time grab the modified -a file and do a test.

The following values ​​were now displayed for the modified TestPCM.wav file -m and -a:

Peak: 100%

Average: 53.09

We see that the average level (volume) has increased dramatically and is in a good volume level. Now we run Pazera again and convert the modified TestPCM.wav file -m and -a to an mp3 file. We run MP3gain and input this new modified mp3 file and perform a track analysis which yielded:

Volume: 94.4

The MP3gain showed an increase in volume from 82.6 to 94.4, approximately 12 db of gain, which corresponds to the peak gain of 2.184 db and an amplification gain of 10 db.

The AVI file was then converted to DVD using the -m and -a modified TestPCM.wav as the audio input sound which would automatically replace the audio with which the AVI was created. When playing on the TV, the audio volumes were fairly even and within the average TV volume levels. This was a dramatic improvement over converting the AVI file with the audio it was created with.

Now we can summarize the correct procedure to normalize AVI file before converting DVD.

Step 1:

Using Pazera, extract the audio file as an mp3 file first, which is normally what it should be.

2nd step:

Using MP3gain, perform a track analysis to determine the volume level.

a) If the volume level is around 82, go to step 3.

b) If the volume level is around 92 dB or more, do the following:

i) Using Pazera, extract audio to PCM wav format, sample rate doesn’t matter

ii) Using the Pers-o-frontend GUI, modify the PCM wav with only the -m 100 option

iv) Convert AVI to DVD using modified PCM wav -m as audio video source.

Step 3:

i) Using Pazera, extract the audio as PCM wave again, sample rate doesn’t matter.

ii) Using the Pers-o-frontend GUI, modify the PCM wav with only the -m 100 option. Take note of the gain the program uses to increase the peaks to 100%, say x db.

iii) Still using the Pers-o-frontend GUI, enter the modified PCM wav -m but now go to the -a option set for a gain of (12-x) db.

iv) Convert AVI to DVD using modified PCM wav as audio video source.

So far this AVI normalization method has worked very well in creating good DVD volume levels.



Source by Joseph Schembri

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