YouTube music video SQ

YT sounds really good on my home theatre system, comparable to stereo.

why is it so good?  We are all very lucky if you watch music vids which I do.
Maybe your system isn’t adequate to differentiate, it is a theatre system after all. YT bit rate is just 256 kbps I believe, otherwise known as lossy and bad sounding.
@jaybe ,

No, it's even worse, it's usually 128kbps! 

Just goes to show how good 128kbps is!

256kbps would be indistinguishable from CD for all intents and purposes. 

Actually, I don't believe you are into high end audio, or just don't know what it is, if you feel 128 kbps sounds good.

Some folks are happy with a Walkman.
Using Apple TV 4K box may be helping YouTube music vid sound.  Could Be my home theatre is really good.
I watch/listen to a great deal of streaming video: Voice; X Factor; Songland; YouTube, Netflix; Amazon Prime, Hulu, Viki;

It’s called Dammmmnnnn Good Enough. Some is lower quality, as with anything.

Your senses are taken by the video as well as the audio, not as critical as concentrating on subtlety of imaging and refinement of music only. Surround Sound, when good adds to the experience in a non-concentrating but immersive and effective way.

I often try using 2 channel mode for some streaming video, often the original was 2 channel and weirdness gets introduced somewhere.

You are quite correct. I’m not into ’high end’ (boutique) audio.

I’m more interested in high performance audio. Always was, and always will be.

With high performance audio there is a clear connect with good sonics, with the so-called ’high end’ I find there is just as often a huge and expensive disconnect.

I know it’s oh so easy to denigrate 128kbps audio, but for uncomplicated solo guitar/vocal music it’s virtually indistinguishable from CD quality.

In fact one of tracks chosen in the development of the MP3 format was Suzanne Vega’s ’Tom’s Diner (a capella)’.

The Fraunhofer Institute considered it acceptable enough at 128kbps to launch the format way back in 1995.

However for audiophiles the use of 128kbps is currently the main problem with evaluating equipment sound on YouTube. It’s pretty good, but not quite good enough.

320kbps is what I use to rip my music for portable use, but I’d be more than happy to see YouTube step up to 192kbps or above.

If they can do this, it might have huge implications for comparitive online demonstrations.

There’s a lot more on this subject here from the good guys at Audioholics.

YouTube Listening Comparisons : Useful or Misleading?