HDMI and high FPS

[clebio]

What are your thoughts on using something like a GoPro Hero3+ (or higher), which support both 1080 HDMI video and 120 frames per second?

I don't know offhand of a way to input two HDMI video signals to a computer (even a desktop PC). Would it have to be converted to USB (treated like a webcam)? Seems like that would degrade the video quality, but then the Oculus doesn't actually render 1080 video.

The possibility of higher fps seems more interesting. The video could still be converted to analog USB, but having 120 fps should help with the responsiveness and immersiveness of the feed, I suspect.

Any thoughts on whether such hardware would work and whether the rendering pipeline would preserve a higher frame rate?

[Matsemann]

I've never tried transferring digital video wireless, so not sure how that would work. I have tried my setup with GoPro, using a cable like this http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=33609 to get analog video and transfer that the normal RC / FPV way over 5.8GHz. Never tried with high fps, though, I just use it to see where the GoPro is filming.

For the pipeline; Not sure if the GoPro outputs all frames to AV, if the transmitter handles it or if the digitizer can handle it. So a lot of uncertainty there. Maybe I will test it when I get my GoPro 4 Black Edition in a few days, but it can be hard to measure. Did I just read 60 frames where most of them were equal, or did I see "actual 60 fps"?

[clebio]

Hmm, didn't think about that, but you're probably right: the GoPro probably records 120fps, but doesn't output that high to AV. In fact, AV is analog, so maybe FPS isn't even relevant? I'll ask my friend that's a video editor....

What do you mean by 'actual' 60 fps? I don't follow.

Thanks for the feedback, either way! I'll test some of this out myself and let you know, but still trying to decide on hardware before I go shopping.

[iguana]

The GoPro analog video output is NTSC, which is 29.97 FPS.

The HDMI output details are here: http://gopro.com/support/articles/hero3plus-hdmi-output-information

The HDMI delay is 3 frames, so 100ms for 30fps video, 50ms for 60fps video.

Having used the GoPro for FPV, I switched to a 600tvl sony CCD board camera, and the quality on the board camera is much higher, especially with the dynamic white balance and all the other fancy stuff Sony puts on those board cameras.

On Thu, Oct 30, 2014 at 9:48 AM, Caleb Hyde notifications@github.com wrote:

Hmm, didn't think about that, but you're probably right: the GoPro probably records 120fps, but doesn't output that high to AV. In fact, AV is analog, so maybe FPS isn't even relevant? I'll ask my friend that's a video editor....

What do you mean by 'actual' 60 fps? I don't follow.

Thanks for the feedback, either way! I'll test some of this out myself and let you know, but still trying to decide on hardware before I go shopping.

— Reply to this email directly or view it on GitHub https://github.com/Matsemann/oculus-fpv/issues/6#issuecomment-61126149.

Eli Yelluas 408-365-4ELI

[clebio]

Thanks for the input. Based on this page, it looks like 600tvl is roughly equivalent to the 728x488 CMOS Camera Module mentioned in this repo's README. I guess then it comes down to refresh rate or frames per second, and maybe the auto-gain adjustments like @iguana mentions (though I'd expect the GoPro to have those too).

There's also the overhead of having to power-on the GoPro and possibly start recording, versus with the CCD/CMOS cameras, I assume they're always-on once power is provided.

Feel free to add more feedback, but you can close this issue if you'd like. I think I have enough to work with. Thanks again!