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  1. Hey there,

    I was trying to search the web to get some proper info about how could I fix some ac3 movie files with the problem described in the title but couldn't find what I exactly want. I completely lost in results telling about particular hardware receiver units, playback settings of various player tools and huge amount of stuff I'm not interested in at all because I play these movies in whatever environment (various standalone dvd players with television, computer systems, etc) they have all the same problem - so it's about the ac3 audio file and not about the playing environment.

    So I have some xvid / mkv movies with the said problem. I already extracted/demuxed the original audio files from them. Some of those are 5.1 some are only 2.0 stereo but the problem is the same. I tried to fix them with eac3to which is my favorite ac3 editing tool but no success (I'm not an expert, though).

    I've read about Dialog Normalization people say that one is nothing to do with this issue and also about Dynamic Range Compression but I don't know any tool with the ability to change it.

    So, to make it all the way clear could anyone help me please how on Earth can I fix those AC3 files to make dialogs louder while keep action scenes at their original volume?

    Thank you much in advance!
    Last edited by Voxx; 19th Jun 2014 at 08:15.
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  2. If your willing to spend alot of time separating the parts you want to increase the volume for, selecting the specific parts, and then changing the volume for just the selected parts, I'm betting Goldwave can do this.
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  3. Thanks for the suggestion!

    I just tried out Goldwave's options, Normalize to 0 dB does not work since most effects are much more louder. Also tried to play with "Auto Gain" and "Shape Volume" commands but wasn't able to modify the existing presets for some reason. Selecting and lowering the effects' volume level one by one is not an option because it may take a whole year or so. The closest one was Auto-gain's peak reducer preset. I'll try to play some more with it when I get to home from work today.
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  4. Member
    Join Date: Mar 2008
    Location: United States
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    Originally Posted by Voxx View Post
    Thanks for the suggestion!

    I just tried out Goldwave's options, Normalize to 0 dB does not work since most effects are much more louder. Also tried to play with "Auto Gain" and "Shape Volume" commands but wasn't able to modify the existing presets for some reason. Selecting and lowering the effects' volume level one by one is not an option because it may take a whole year or so. The closest one was Auto-gain's peak reducer preset. I'll try to play some more with it when I get to home from work today.
    For 5.1, I usually pass it through FFDshow 2.0 mixer and see if that equalizes the audio.
    I open the file using directshowsource and save the 2 channel wav in Virtualdub (passing through ffdshow mixer).
    I don't care if it 5.1 or not,so this often does the job.

    However, if the problem exists and the file is already 2-channel, you'll need to modify the dynamic range in
    an audio editor. This has the effect of lowering the loud parts and raising the quiet parts.
    For example, have a look at this image in Sony Sound Forge. You can see from the settings that
    peaks above -9 dB are reduced (determined by the "ratio" in Sony's tool) while everything at a lower level
    is not modified by this formula. Then the whole file is raised by "output gain" on the left.

    See if Goldwave or Audacity has something similar.
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  5. Member
    Join Date: Jul 2012
    Location: Europe
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    Originally Posted by Voxx View Post
    Hey there,

    I was trying to search the web to get some proper info about how could I fix some ac3 movie files with the problem described in the title but couldn't find what I exactly want. I completely lost in results telling about particular hardware receiver units, playback settings of various player tools and huge amount of stuff I'm not interested in at all because I play these movies in whatever environment (various standalone dvd players with television, computer systems, etc) they have all the same problem - so it's about the ac3 audio file and not about the playing environment.

    So I have some xvid / mkv movies with the said problem. I already extracted/demuxed the original audio files from them. Some of those are 5.1 some are only 2.0 stereo but the problem is the same. I tried to fix them with eac3to which is my favorite ac3 editing tool but no success (I'm not an expert, though).

    I've read about Dialog Normalization people say that one is nothing to do with this issue and also about Dynamic Range Compression but I don't know any tool with the ability to change it.

    So, to make it all the way clear could anyone help me please how on Earth can I fix those AC3 files to make dialogs louder while keep action scenes at their original volume?

    Thank you much in advance!
    I have done this with WaveLab on stereo files with good results.



    Here is a mini tutorial

    you need convert ac3 to wav and finaly convert wav to ac3 again.

    because the WaveLab not support ac3 files.


    1 - open audio file.

    2 - apply level normalizer

    3 - open loudness normalizer dialogue box

    4 - config loudness normalizer like this.

    .... Desired loudness = "-12db"

    .... Max peak level = "0"

    .... Softness = "0"

    .... check the "remove DC offset" checkbox

    .... Maximum number of passes = "5"

    .... the rest of the settings lets stay default

    .... click on "Statistics" button and wait until finish will open one more dialogue box.

    .... look at Statistics dialogue box and memorize the following values:

    .... value "Loudness (RMS), left and right"

    .... value "Peak compression is required, left and right"

    .... close Statistics dialogue box.

    .... put the Loudness (RMS) values in - Desired precison +/- setting

    example: if Loudness (RMS) left is 28.34db and right 25.36db

    you need put 29db in Desired precison +/- setting


    .... put "Peak compression is required" value in - Autorized peak compression setting

    example: if Peak compression is required left is 1.96db and right 6.32db

    you need put 7db in Autorized peak compression setting


    .... when you have done this click on render button and wait until finish.


    .... Now you fixed the problem.

    5 - close loudness normalizer dialogue box

    6 - choose Eliminate DC offset in process menu and wait until finish and save your file.


    I hope this help you
    Last edited by mx101; 20th Jun 2014 at 02:26.
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  6. If you're interested, I posted some details regarding how I "compress" the audio on playback in this thread. As I use a PC for playing video I compress the audio on playback rather than encode it compressed, but there's no reason why you can't compress it while encoding using the same method.

    One thing I seem to have forgotten to mention in that thread.... I use ffdshow's mixer filter to downmix 5.1ch audio to stereo, and I set it to boost the volume of the centre channel, given that's where the dialogue tends to be.

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  7. thank you very much for all the great tips / guides, I will try them out when I get to home.
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