why does GoPro say 2.7k is 16:9 aspect ratio?

[jcarst85]

Hi there,

My GoPro Hero 4 Silver manual says 2.7K (2704:1520) is a 16:9 aspect ratio, but when I put it into the aspect ratio caluclator here, it says the aspect ratio is 169:95. I totally understand GoPro aren't making a mistake by labeling it 16:9, but could someone please just explain to me why the resolution for 2.7k is not a standard 16:9?

I wanted to use the 2.7k as a better quality alternative to 1080P when filming at 30fps (Hero 4 Silver only does 4k at 12.5 and 15fps), but if it isn't the standard 16:9 aspect ratio, I don't think there's much use in me doing this.

Thanks a lot for any assistance offered.

Regards
Jamie

[newpball]

Well what resolution would you propose?

2704 x 1521?

It would be closer but most codecs would not like it!

Personally I would like to see more cameras supporting 2.5K (2560 x 1440) resolution.

[manono]

2704/1520=1.778947368421053
169/95=1.778947368421053
16/9=1.777777777777778

Pretty close, I'd say. I would guess they wanted something that's Mod16 (or 8).

[jcarst85]

I see, so it is literally only 1 pixel away from being 16:9. I wasn't aware of that (my maths being rather terrible).

Mod16 (or 8).

What is Mod16/8? Sorry, bit of an amateur here.

As I do a bit of stabilization in post (Vegas Pro 12), would it be a good idea then to film in 2.7k, which will then provide a bit of flexibility to do stabilisation?

[poisondeathray]

mod16 means some multiple of 16, mod8 means some multiple of 8. In video these are important numbers because of the way common compression schemes organize the data into macroblocks

In general , it's better to use the highest resolution mode available on any camera. Not sure about this model of gopro, but lower resolutions on many cameras are often pixel binned, line skipped or otherwise inproperly processed (they leave poor aliasing artifacts). Most cameras have a sweet spot and perform more poorly at other modes. You'd have to look at some technical reviews of the sensor and processing

[jcarst85]

Great, thanks a lot!