Solution to stuttering and dropped frames when watching high‑resolution 60fps YouTube videos in Chrome
On my old Core 2 Duo machine, watching high‑resolution 60fps YouTube videos in Chrome resulted in obvious frame drops. Using the video stats (Stats for nerds), I could see that at 1080p 60fps the dropped frames counter kept increasing. At the same time, both CPU cores were maxed out. Clearly, the HTML5 video player was not using hardware decoding.
At first I thought it was a Chrome settings issue. I toggled the hardware acceleration option and restarted Chrome, but the problem remained. After searching online, I found that due to some behavior in Chrome (many people reported that Firefox and newer versions of IE do not have this issue), YouTube sends VP8/VP9 encoded video streams (also visible in the stats panel). These formats do not support hardware decoding on older hardware, so the CPU becomes fully loaded and frames are dropped constantly.
Therefore, the solution is to force YouTube to send a hardware‑decodable format. Fortunately, someone created a Chrome extension that does exactly this: h264ify: https://chrome.google.com/webstore/detail/h264ify/aleakchihdccplidncghkekgioiakgal, After installing it, YouTube starts sending AVC‑encoded video instead. CPU usage drops significantly, and the frame‑drop issue improves noticeably.