Making several videos have the same volume

The process of several videos have the same volume, also called normalize multiple video files. These videos can be movies, YouTube videos, or other sources.
The normalization of multiple video files at a time, can be obtained in two ways: either temporarily or permanently. We will discuss the program to normalize the sound of the videos, but if you want to do just to MP3, there is another alternative program .
The temporary, means using the program that visualize videos (to such programs are called "video player"), if the program is minimally good in their settings audio should have an option to activate Normalizing audio.
For example in the player called VLC (for me the best and above is free) you can find this option in
Tools -> Preferences -> Audio -> Filters -> box that says: Volume Normalizer.
The permanent form means either manually or automatically with a program to make multiple videos have the same volume, you must perform the following steps:

• Extract audio track.
• Normalize the volume to 89db (is the optimal point, if it gets stronger or appears distorted sounds like a fried egg friese, if it gets lower at times is too low).
• Coding standard audio track.
• Replace the old audio track of the video by the new.

This is achieved do everything automatically with a free program called "BS FAG" whose official website is this , or you can download the program directly from Freewarefiles is now version 2.5.1.
The manual of this article is based on the "Version 2.3.0 BS FAG "but recommend that you use the updated version" BS FAG 2.5.1 or later ". Once you've downloaded and installed the program, you can start. When you run it can do two things: either press the "Add" button or drag the videos to the program window. Then you click the button below that says "Process" and you're done, the program will do everything automatically.

Once you have completed the process, all processed videos have the same volume. In the "Gain" column volume gain appears, as seen in the image on some videos was uploaded them more volume than others, because the volume was lower than the other videos and the program compensates by raising a little more volume than the rest.
And finally, if when you select videos to make the normalization of sound, and get a mysterious error message (I say mysterious because you do not clarify anything), it is usually due to two reasons:

• Not a video file (eg if you put an image, or an MP3 music file type).
• It is a correct video, but has "non-English characters". For example the name contains accents, ñ, ce trencadas ("ç"), umlauts, "eles geminadas", etc. If you pass this, rename the file with the same name but replaces the "letters problematic". For example "The f u tbol Bar ç a 2005.avi" and would "tbol The f u c a 2005.avi Bar".

I forgot in the configuration section you can pass parameters to modify the result, although it is quite complex. Who would be interested, these parameters can be found in the section dedicated to the volume of FFmpeg program (in English).
If you like the advanced options, you can research how to do this normalization process using more sophisticated techniques. I recommend the mini guide videohelp.com Forum (in English), which explain programs to extract data from audio and tricks for standardization, using batch type processes BATCH.
I hope this article helps someone to save time, because my cost me a lot to find a program. :)