Would you like to enjoy the music on a DVD and transfer it to your PC? Use Audacity, the free, open-source, and multi-platform audio editor capable of decoding a wide range of formats with FFMpeg and LAME MP3 libraries.
Download and install Audacity first from the following link:
To benefit from export and import features, we need to install the MP3 Blade codec and the FFMpeg library specially designed for Audacity:
You now have all the tools to decode your audio streams.
N.B. : Don't forget to choose each of the above libraries based on your operating system.
Import the audio stream of a MKV file
MKV files contain both audio and video streams. It is possible to import a 5.1 stream and then export it in stereo by merging the tracks. However, note that it is unnecessary to try to keep data in 5.1 if you do not have the right equipment (sound card and 5.1 speakers).
Start Audacity and open the menu File. Do then Import then select Audio...
Then locate your video — a MKV file in our example, from which you want to extract the sound. Wait a few moments, time for Audacity to plot the flow curve.
It’s very likely that you don't want to export the entire soundtrack. Make a selection directly on the track or use the digital tools at the bottom of the window.
By entering the start and end values, you will gain in precision.
Export audio to MP3 or other
The selection made, make File then Export selection... Enter a file name and select MP3 Files from the audio drop-down list. To adjust the quality of the final file, click on Options... then increase the quality to 320 kps.
Make OK to validate and then Save to start the export process.
Fans of sound editing will not be content with an MP3 file and will prefer loss-free formats such as Apple AIFF or FLAC.
Audacity is definitely a Swiss knife essential to edit its audio files. The richness of this software would require the creation of a section on its own!