system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why speeding up the video on youtube doesn't change the pitch but when the same thing is done using some other software the audio starts sounding like an alien?

Edit : Its how instead of why.
gpt
Sound is in the form of waves. Lower pitch is longer waves and higher pitch is shorter waves. When you speed up a piece of sound the time between the waves gets smaller and you end up with a higher pitch sound. It is possible to change the pitch of sound without altering the speed but this is expensive to process and hard to get right. The YouTube playback is able to do this but note that the playback speed is limited to a few select values and not too fast or slow and that there are sound artifacts in the result. This is because they are taking shortcuts to improve processing time and still have a problem with the quality. A lot of software is able to do similar processing with different limits on the processing. A common thing is to drop the sound at over 4x speedup as it just sounds terrible. Even TV stations with top of the line equipment for this processes the sound separately and either plays the sound at normal speed making cuts where logical or replace the sound entirely with folly or music.