5

Is it possible to separate voice and background music from a video file?

I only need the background music.

Type of video: MP4

Working on Windows XP 32 bit SP3

4

Unless they're separate audio tracks in your video, not easily. What you'll probably have to do is extract the audio track from the video into a separate file, edit the audio file with a dedicated tool, then remux the result back into the video.

The demux/remux part is easy. What's going to be difficult is attempting to isolate the background music. You'll probably have to experiment with different effects, all of which will most likely result in either a significant loss of fidelity in the audio or not entirely removing the dialogue, if not both. What's more is that you're going to be re-encoding that output into a new mp3/aac file, and between the re-encoding and audio processing, your output is going to sound much worse than the original.

You may have better results by trying to re-master the background music and replacing the audio track in the movie file entirely.

  • replacing it would be crazy and hopeless, since I am just music lover, I don't know anything else about music. Is there any 3rd party program out there which can help me? – SpongeBob SquarePants Feb 14 '11 at 17:08
  • No, unless you have source material with separate tracks for the various audio pieces, separating out music from voice is extremely difficult and for the tools there are out there that claim to do it, quality is always poor. – BBlake Feb 14 '11 at 17:42
5

Audacity – a free and open-source cross-platform audio editor – can do this, using the Vocal Reduction and Isolation effect. You should first extract the audio from the video file, e.g. using ffmpeg:

ffmpeg -i video.mp4 -c:a pcm_s16le audio.wav

And then load the audio.wav file into Audacity:

If you only want to get background music, select the Remove Vocals option; if you want the opposite, choose Isolate Vocals.

Note that this is never going to sound perfect. Vocal isolation is a hard task, as everything you hear is basically mixed into two tracks. An algorithm will never be as good as your brain in isolating different sound sources. Your audio source should be a stereo file with the vocals being panned dead-center. It might also produce false-positives, removing other instruments in the process.

  • This was one of best tutorials I've read about Audacity. Underrated answer. Thank you very much :) – Zeta.Investigator Dec 2 '17 at 18:59
  • Is it just a band-pass filter? Then what is "Strength" meaning in this? Does is attenuate the amplitude of the out-of-band signals or does it have something to do with power (or log of power)? – Zeta.Investigator Dec 2 '17 at 19:01
  • 1
    @Zeta.Investigator Just briefly skimming the article and the source code, it appears to be the power of the band pass / band stop that will be added or subtracted from the center. Apparently it's normalized by the difference between 1) the power of the middle vs. overall signal and 2) the power of the side vs. overall signal. Then it's exponentiated – so I assume it's on the log scale. (But I'm not an expert on this kind of processing or LISP.) – slhck Dec 3 '17 at 11:30
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I managed to remove background conversation/noise from a video by running a low-pass filter that was built in to the editor that I was using. The whirrs of my robot, which was the target of my video, remained.

Note that I am not an audio expert, and I cannot guarantee this will work for your particular case, but it's worth a try.

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