3 ms·

Not surprisingly, "You won't be able to do this [computationally hard thing]" is a prediction that doesn't age well. :) The most recent benchmarks I've seen sh

Not surprisingly, "You won't be able to do this [computationally hard thing]" is a prediction that doesn't age well. :) The most recent benchmarks I've seen show HEVC encoding to be 10x-15x slower than H.264, and 4K is 4x the pixel count of 1080p. Naively, this would make UHD 40x-60x more computationally intensive than 1080p, but it is probably not quite that bad. (4x pixel count should be a bit less than 4x computation.) Latency isn't really a factor here, though. UHD doesn't have higher latency than HD; both just need to fill a few seconds of buffer in the player, and as long as they can keep up with a stream in real-time, this will only take a few seconds to do. > What do UHD recorders do to record UHD material -- just massive iframe only codecs? Yes, but the use of iframe-only is orthogonal to the delivery codec or format. (Most pro video is shot and edited in an intra-only codec.)

isostatic 8y ago
Sure, I wondered if there were any non-iframe only encoders out for recording uhd
- namibj 8y ago
  Well the 300$ Sony action cam in front of me can shoot 2160p30 @100Mbit/s in good quality, considering the form factor. A nicely clocked Nvidia GPU can also use it's H.265 encoder to record at double that, both bandwidth and framerate. These are I/P frame coders, at least you'd not want to use B-frames at these speeds as more effort in your P frames yields more ROI. Intel should, as part of QuickSync, also offer such acceleration, but I am not sure how much that encoder can handle. I am confident it can do something in UHD with P-frames, but I have no idea how good it feats compared to the Nvidia encoder. If the UHD coding is within it's design range, it should yield higher quality though, albeit at barely enough frame rate. If you try, you can push over 100 fps through the Nvidia one, but quality will suffer even more.
namibj 8y ago
At these delays you can use sharded coding with clustering. I.e., at a GOP of say 10 seconds, this gives you 8 shards. And with that many shards, I think a nice blade center full of high-clock current-gen CPUs can do it. I.e., 8 systems with as many max speed cores each as the encoder can handle. x264 for example caps out at about 20~60 cores for 1080p, but I didn't save the exact numbers.
- ttoinou 8y ago
  Note : it seems that for live TV the GOP is more like 2 seconds
  - namibj 8y ago
    10 seconds is a good balance between seekability and gains due to B-frames, for normal movie content. If the movement is particularly absent/easy to compress, e.g. with screen recordings of Minecraft (as long as there are not too many particles around), one benefits from a much larger GOP, towards the minute and even over a minute. Though you pay for this with most of the seeking you could do before. Choose wisely depending on what it's for.
- dan1234 8y ago
  GOP = Group of Pictures[0], for anyone unfamiliar with the term. [0]https://en.wikipedia.org/wiki/Group_of_pictures https://en.wikipedia.org/wiki/Group_of_pictures

isostatic 8y ago

Sure, I wondered if there were any non-iframe only encoders out for recording uhd

namibj 8y ago
Well the 300$ Sony action cam in front of me can shoot 2160p30 @100Mbit/s in good quality, considering the form factor. A nicely clocked Nvidia GPU can also use it's H.265 encoder to record at double that, both bandwidth and framerate. These are I/P frame coders, at least you'd not want to use B-frames at these speeds as more effort in your P frames yields more ROI. Intel should, as part of QuickSync, also offer such acceleration, but I am not sure how much that encoder can handle. I am confident it can do something in UHD with P-frames, but I have no idea how good it feats compared to the Nvidia encoder. If the UHD coding is within it's design range, it should yield higher quality though, albeit at barely enough frame rate. If you try, you can push over 100 fps through the Nvidia one, but quality will suffer even more.

namibj 8y ago

At these delays you can use sharded coding with clustering. I.e., at a GOP of say 10 seconds, this gives you 8 shards. And with that many shards, I think a nice blade center full of high-clock current-gen CPUs can do it. I.e., 8 systems with as many max speed cores each as the encoder can handle. x264 for example caps out at about 20~60 cores for 1080p, but I didn't save the exact numbers.

ttoinou 8y ago
Note : it seems that for live TV the GOP is more like 2 seconds
- namibj 8y ago
  10 seconds is a good balance between seekability and gains due to B-frames, for normal movie content. If the movement is particularly absent/easy to compress, e.g. with screen recordings of Minecraft (as long as there are not too many particles around), one benefits from a much larger GOP, towards the minute and even over a minute. Though you pay for this with most of the seeking you could do before. Choose wisely depending on what it's for.
dan1234 8y ago
GOP = Group of Pictures[0], for anyone unfamiliar with the term. [0]https://en.wikipedia.org/wiki/Group_of_pictures https://en.wikipedia.org/wiki/Group_of_pictures