Transpose - Pitch - Loop for Videos is a cool little Chrome extension that allows you to manipulate the speed, pitch, and also transpose YouTube videos.

The idea was made with musicians in mind to learn music by slowing it down so you can hear an intricate bass part, for example, and copy the notes. But if you have ever listened to some instructional or how-to videos where the author speaks to quickly or they sound like they have marbles in their mouth, then you'll appreciate this extension.

Transpose - Pitch - Loop for Videos comes in two versions. The free version includes the ability to change the pitch by a semitone or finetune, control the playback speed, and repeat between two-time markers. It also allows you to jump directly to a time marker and control the video from its interface (play, pause, forward, and rewind). The paid or pro includes the same but additionally allows for high-quality audio pitch & transpose, remember settings for each video, history list, unlimited Loops, dark theme, and a few others.

We tested it out on a few different videos of varying music and speaking audio. And it performed as detailed without any noticeable issues other than a little hesitation when rapidly sliding speed control to super slow. Still, we can't be sure that this wasn't caused by using it in VMWare - other than that, it can be a useful and free option to help decipher music and other videos.