Comment Re:Warning from ccalam in the second video (Score 2, Informative) 234
The high quality version of the audio will have the 19 (or up to 22.1) kHz sine wave
Actually not; it gets filtered out by YouTube's compression algorithm. Here's a demo video with spectrograms showing the audio before upload and as received from YouTube (after compression); you'll see that the sine tone is completely removed (though there are other distortion artifacts that are not).
