Você pode usar os vídeos h264ify (também tem vídeos com versão do Firefox ) .
h264ify is a Firefox/Chrome extension that makes YouTube stream H.264 videos instead of VP8/VP9 videos.
Try h264ify if YouTube videos stutter, take up too much CPU, eat battery life, or make your laptop hot.
By default, YouTube streams VP8/VP9 encoded video. However, this can cause problems with less powerful machines because VP8/VP9 is not typically hardware accelerated.
In contrast, H.264 is commonly hardware accelerated by GPUs, which usually means smoother video playback and reduced CPU usage.