I work with the author and have seen how difficult some of these challenges are to solve. It's a classic example of the final 20% hiding 80% of the complexity. A/V sync in particular is a really deep subject full of <i>fun</i> footguns and pitfalls. It's been very satisfying watching the puzzle come together.<p>Would be very interested to hear if anyone else has come across similar things while working with headless chrome.