Extracting the audio content from videos, whether they're documentaries, music videos or movies, might cause significant sound quality loss. One efficient way to complete this task is by using a video to audio converter that can help you preserve the original sound of the video. A good example comes from 4Media MP4 to MP3 Converter.
Although its name says one thing, the program actually supports a wide range of input formats, besides MP4. You can batch convert as many videos as you like, select the audio quality that best fits your needs and even write down or paste the lyrics for each converted file.
An aspect I like about this program is that it was created for professional users as well. The application comes with a separate advanced settings menu where you can adjust the audio stream configurations and modify the metadata details.
However, a small drawback that caught my attention was that the program sometimes fails to convert videos with other format than MP4. But, as the application is called 4Media MP4 to MP3 Converter, I guess you can overpass this flaw.
To be honest, I've found 4Media MP4 to MP3 Converter to be of good use as it offered me high-quality results in just a few moments. And since you don't have to pay much to use it, I guess you should give it a try.