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Modifying mp4 video files...

Posted: Mon Jun 17, 2019 5:56 pm
by tenfoot
I have several .mp4 files where the music is too loud. So much so, in fact, that it is impossible to clearly hear the singer. Is it possible to modify the video by reducing the loudness of the music and retaining the volume of the vocals. All I have learned by searching the internet is that the music is stereo and the vocal is mono, and all I can find is how to remove one or the other - mono or stereo.

If this is possible, what software should I use and are there any tutorials on Youtube I can look at, please?

Re: Modifying mp4 video files...

Posted: Tue Jun 18, 2019 12:47 am
by kukamuumuka
With Kdenlive you can do it, but maybe is easier to extract an audio track using SoundConverter amd set sound level using Audacity, and then re-join the track using some video editing application like Avidemux.

Re: Modifying mp4 video files...

Posted: Tue Jun 18, 2019 9:55 am
by Hoser Rob
I'd use avidemux ffor this, I have, but not for this exect reason. I'd also use audacity ... just open the video file with it, it'll extract the audio stream. But I'd try a normalization filter myself too.

After you have the audio track, open the video file with avidemux, set the video to Copy mode, select the audio file as external audio, and set the audio to Copy mode. Avidemux is good for this, it's fairly simple, and most importantly it doesn't enforce an ouput pixel resolution on you. With other editors you can end up re encoding video when you don't want to.

Re: Modifying mp4 video files...

Posted: Tue Jun 18, 2019 3:50 pm
by tenfoot
Thank you administrollaattori and Hoser Rob for your reply. I'll try the methods you suggest to see how I get on.

Re: Modifying mp4 video files...

Posted: Tue Jun 18, 2019 4:22 pm
by Flemur
tenfoot wrote:
Mon Jun 17, 2019 5:56 pm
I have several .mp4 files where the music is too loud. So much so, in fact, that it is impossible to clearly hear the singer. Is it possible to modify the video by reducing the loudness of the music and retaining the volume of the vocals.
Sort of, and it depends. Normalizing won't do it.
All I have learned by searching the internet is that the music is stereo and the vocal is mono, and all I can find is how to remove one or the other - mono or stereo.
Often, but not always, the vocals are closer to "mono" (not actually mono, though) than instruments are; you've probably found "vocal removers" which do the opposite of what you want to do.

So, in audacity, or other audio editor, you could remove the vocal, then subtract the vocal-less audio from the original audio. In adobe audition the subtract would be done with an inverted "mix paste"; I rarely use audacity, but apparently that's possible...

Internet searches on

Code: Select all

audacity remove vocals
audacity mix paste
return a lot of stuff. I think you need to do all this in one program (not remove the vocal with a another program, then save a file) because the audio needs to be sample-aligned to do the subtraction.

Edit: I noticed this while doing something else:
audacity (menu) -> Effects -> plugin 16-17 -> vocal remover.