Based on my experience and some brief research I don't think this is generally accurate. While I'm sure some combinations of encoder and bitrate might be an issue, YouTube is actually delivering rather high quality audio on HD videos. There's nothing inherent to Joint Stereo encoding that would make binaural audio not work, it's the default choices encoders make at low bitrates.

OP here. I built this engine because I realized auditory entrainment (for focus and my own Aphantasia) is often compromised by standard streaming platforms.

Most codecs (MP3/AAC) use "Joint Stereo" (Mid/Side coding) to save bandwidth. Since binaural beats rely entirely on the subtle phase difference between Left/ Right channels, compression algorithms tend to treat that data as redundant and smooth it over.

I didn't want to leave it to chance, so I moved the stack to the Web Audio API. It generates the sine waves in real-time (client-side), ensuring mathematical precision and perfect channel isolation.

Happy to answer questions about the physics or implementation.