A bitrate is not a quality.

Every bitrate is quoted per second, and a second holds a different number of pixels in every row of every recommendation table ever published. What decides whether a frame survives the encode is what each pixel gets: bitrate ÷ (width × height × fps).

The engine is free and needs no account. YouTube's own figure for 4K30 is 45 Mbps — 0.1808 bits per pixel. X's figure for 720p30 is 5 Mbps — 0.1808. The same number, on nine times the bitrate, because the 4K frame has nine times as many pixels to cover. And YouTube's own 1080p60 figure of 12 Mbps is 0.0965, barely half of either, sitting near the top of every list because the lists are sorted by bitrate. One recommendation page spans 1.88× in the unit that matters. And the three things people do to improve a video — more resolution, more frames, upscale the master — all divide that budget: 8 Mbps at 1080p30 is 0.1286, and the same bitrate upscaled to 4K is 0.0322. Every lane ships a worked example that costs nothing. Writing the report needs credits.