3 ms·

> 20ms motion-to-photon latency > so 1ms wouldn't be a big deal Even if it's 1ms, that means that you only have 19ms left for all of the processing / renderin

by pyre 12y ago

> 20ms motion-to-photon latency > so 1ms wouldn't be a big deal Even if it's 1ms, that means that you only have 19ms left for all of the processing / rendering, including to the I/O delay of getting motion data from the input.

melling 12y ago
How much more work can you do on a desktop CPU/GPU in 19ms than on the mobile hardware? If the desktop hardware is 10x faster, wouldn't it still be a win? Also, consider that you might allow for a small window for when things don't go as planned. So, 15ms to do the computations, for example.
- pyre 12y ago
  This is all assuming a hard 1ms transmission latency. Usually numbers like that are averaged and this seems like a use-case where 1ms would be an upper bound instead.
  - jacquesm 12y ago
    That's a really good point. The tech I'm referring to is used in high end (military simulation) gear but it is definitely todays technology and from what I can read it is an upper bound, not an average but that could be marketing, I haven't tested this stuff. But I've been following the 'wearable dual display' setup since a friend of mine built one in 1983 or so (using two very small monitors mounted to the side of a helmet and a bunch of mirrors (2 100%, 1 50%) to put the image in front of the eyes and that's the best latency for wireless that I've seen to date. Given that is a small fraction of the framerate and a latency rather than a throughput limit (so a constant offset rather than a limitation on quality) it imposes a small overhead (at 50 fps that's 20 ms/frame so 5% of the total time budget). That seems a good trade-off versus being tethered, you could for instance make up for that by letting the rest of the pipeline generate an image that is slightly worse to achieve the same framerate in an untethered situation. Of course any latency increase will always come at some price the question is whether or not that is an acceptable price for the improvement you get along another dimension all this assuming that's an upper bound. (And maybe there is higher end gear that I'm not aware of)

by pyre 12y ago

melling 12y ago

How much more work can you do on a desktop CPU/GPU in 19ms than on the mobile hardware? If the desktop hardware is 10x faster, wouldn't it still be a win? Also, consider that you might allow for a small window for when things don't go as planned. So, 15ms to do the computations, for example.

pyre 12y ago
This is all assuming a hard 1ms transmission latency. Usually numbers like that are averaged and this seems like a use-case where 1ms would be an upper bound instead.
- jacquesm 12y ago
  That's a really good point. The tech I'm referring to is used in high end (military simulation) gear but it is definitely todays technology and from what I can read it is an upper bound, not an average but that could be marketing, I haven't tested this stuff. But I've been following the 'wearable dual display' setup since a friend of mine built one in 1983 or so (using two very small monitors mounted to the side of a helmet and a bunch of mirrors (2 100%, 1 50%) to put the image in front of the eyes and that's the best latency for wireless that I've seen to date. Given that is a small fraction of the framerate and a latency rather than a throughput limit (so a constant offset rather than a limitation on quality) it imposes a small overhead (at 50 fps that's 20 ms/frame so 5% of the total time budget). That seems a good trade-off versus being tethered, you could for instance make up for that by letting the rest of the pipeline generate an image that is slightly worse to achieve the same framerate in an untethered situation. Of course any latency increase will always come at some price the question is whether or not that is an acceptable price for the improvement you get along another dimension all this assuming that's an upper bound. (And maybe there is higher end gear that I'm not aware of)