How to delete background music

You only need VLC media player and a video editing software.

Open your dvd in VLC. It can work with downloaded versions too if they come from the dvds/blu-rays (it won’t work with something downloaded from youtube or an episode recorded from the tv for example, because all the sound tracks will be mixed into a single one instead of multiple tracks that have different functions)

Once it’s opened go to the scene you want to and click on the record button (if you don’t see it go to View -> Advanced Controls)

Click to record, click again to stop recording. You get a video with a name that starts by “vlc-record”.
Open that video in your editing software. I’m using Premiere here but I have done it in Sony Vegas too and I assume it works with any editing software.

As you can see there are multiple audio tracks. If you have only one track, you can’t do anything. Right-click on the video track and unlink the video and the audio so you can delete some audio tracks without deleting the whole thing.
Find the track that has the dialogue and delete all the others. 

And that’s it, you should have a video without music like these, unless they do that annoying thing where they mix some of the music with the dialogue (they don’t do that with Sherlock). Hope that helps some people!