360 video resolution?


So I stitched / rendered / drawn my 360 in biggest resolution I can. What resolution should I choose for viewing…
It seems the more you investigate the messier it gets. Most of online platforms will allow you to upload what you have and re encode the way they can distribute your video online.
Littlstar tells you -5gb limit and h264 for compression. More details
If you do stereo 360 – you have to contact them for further details.
Youtube is like… give me whatever ..
If you are planing to show your video on specific device with specific software (say gear vr using their player)
You will have to prepare the video in correct resolution, right bit rate and in correct encoder.

Today’s HMD’s have a limited screen resolution of:
PSVR: 1920×1080 (960×1080 per eye)
Vive: 2160×1200 (1080×1200 per eye)
Rift: 2160×1200 (1080×1200 per eye)
Gear VR: 2560×1440 (1280×1440 per eye)

But that’s the number of pixels they can show. Your image typically has to be much bigger. (these devices do not directly show rectangular images – due to lens distortion you (or software of hmd) has to distort the image opposite way of HMD’s lens distortion – so at the end you see an ok looking image.
To achieve this you have to have more pixels. Another thing is field of view. We create a equirectangular image that covers full sphere. But in HMD you see only a small portion of this image (at the time when you rotate your head you see another part of image).
So our big resolution we feed to HMD gets diminished quite a bit when we actually see it through HMD.
Then there is a whole other mess with codecs and their limitations.

So what is .. Recommended (?) / optimal (?) / max (?) output resolution for:

Platform                        Codec                            Resolution               FPS                  Avg. bit rate

Gear VR                         h.265                        3840×2160                            30         10 – 20Mbps
Cardboard       h.264 (Baseline, level 4.2)     3840×2160                     30         20 – 30Mbps
Cardb. iOS      h.264 (Baseline, level 3.1)       1920×1080                      30         10 – 14Mbps
Oculus Rift     h.265 / h.264                           4096×4096                        60         40 – 60Mbps

recommendations taken from here.
The next level of taking advantage of limited HMD resolution and squeezing more quality would be to do clever tricks like Chris Milk is doing.
The idea is to use images in part of your video. But this is a complicated witchcraft not for us mortals..  :)

And probably third level is building your own viewer. Ant that’s programing. so I stop here.

Someone should make a calculator: you input your eq resolution your hmd’s field of view and resolution per eye – and you get a final “on screen” resolution. anyone?

If you are not using dslr/ cg you need a true 360 cam. here is a list with specs:
More reading on these topics:

More thoughts from links:

The ideal format for gen 1 PC HMDs would be 4096×4096 @ 90 FPS, which roughly matches the angular resolution and refresh rate of CV1/Vive, but this can’t be achieved without H.265 Level 6.1 (which is itself impractical due to CPU load – no hardware acceleration for H.265 yet). H.265 Level 6.1 also would provide 5944×5944@60, which is ideal for Gear VR, but again, probably could not be decoded in real time on that device.