When we stream 4k video from Netflix for example, they recommend a minimum speed of 25 mbps.But HDMI 2.0 has a bandwidth of 18.0 Gbit/s
How can we recieve 4k video with a connection speed of only 25 mbps when we need 18.0 Gbit/s to send the video to our TV?
I think it is to do with compressed vs raw 4k but do we really compress it to this an extreme? I would have thought this would result in so much loss that we are no where near 4k in the end.
In: Technology
Netflix, Youtube etc. all compress the hell out of their videos. Video compression is a lossy system, so some of the detail in the image goes away when it’s compressed–the critical thing with the compression algorithms is to try and ensure what goes missing is stuff you won’t notice. Nonetheless, if you were to run the uncompressed 4K video alongside the streamed version you would almost certainly be able to tell the difference.
As for the bandwidth requirements, 4K video is 3840×2160 pixels. You need 3 bytes to store each pixel, so each uncompressed video frame is nearly 24Mb of data on its own. If you’re streaming that video to HDMI at 60 frames per second, then you need a minimum bandwidth of a little bit over 11Gbps. HDMI gives you a fair bit of overhead there, but certainly not so much that you could say 18Gbps is overkill.
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