Most 4k streams are 8-20 Mbps. A UHD runs at 128 Mbps.
Bitrate is only one variable in overall perceived quality. There are all sorts of tricks that can significantly reduce file size (and thus bitrate of a stream) without a perceptible loss of quality. And somewhat counterintuitively, the compression tricks work a lot better on higher resolution source video, which is why each quadrupling in pixels (doubling height and width) doesn’t quadruple file size.
The codec matters (h.264 vs h.265/HEVC vs VP9 vs AV1), and so do the settings actually used to encode. Netflix famously is willing to spend a lot more computational power on encoding, because they have a relatively small number of videos and many, many users watching the same videos. In contrast, YouTube and Facebook don’t even bother re-encoding into a more efficient codec like AV1 until a video gets enough views that they think they can make up the cost of additional processing with the savings of lower bandwidth.
Video encoding is a very complex topic, and simple bitrate comparisons only barely scratch the surface in perceived quality.
Bitrate is only one variable in overall perceived quality. There are all sorts of tricks that can significantly reduce file size (and thus bitrate of a stream) without a perceptible loss of quality. And somewhat counterintuitively, the compression tricks work a lot better on higher resolution source video, which is why each quadrupling in pixels (doubling height and width) doesn’t quadruple file size.
The codec matters (h.264 vs h.265/HEVC vs VP9 vs AV1), and so do the settings actually used to encode. Netflix famously is willing to spend a lot more computational power on encoding, because they have a relatively small number of videos and many, many users watching the same videos. In contrast, YouTube and Facebook don’t even bother re-encoding into a more efficient codec like AV1 until a video gets enough views that they think they can make up the cost of additional processing with the savings of lower bandwidth.
Video encoding is a very complex topic, and simple bitrate comparisons only barely scratch the surface in perceived quality.