Change resolution from 4K 30fps to 2K 60fps

Leaton

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Hello folks

I have orded a 750 2CH but I can change at anytime cos I won't get my car till next month. The reason I went for that is it is 1K at 60fps instead of the 4K 30fps 900 2Ch.

After doing some thinking and seeing another brand accept 4K 30fps being changed to 2K 60fps via settings, which is also an option in a lot of other things, I could not find an answer to this with the 900 2Ch, only for settings such as Ultra, high, etc.

Is there an option to lower it to 2k for 60fps or not?
 
The question is how to get 1440p out of 4k chip.

Do you mean crop the native resolution and therefore reduce FoV or just lower the encoding resolution (which is quite dump approach since 4k is "not divisible" by 1440p)?
 
Well I do not know, but in compters and many devices there an an option to do that, So I do not know why that would be an issue.

It is called downscaling and just need to bunch up 4 pixels to behave as 1 pixel. 1k-2k-4k-8k, each ups pixels by 4x.

Here is a comment by a YouTube poster "recently installed a 4K dashcam and it is great. However, after experimenting with the various settings on the camera and examining the footage, I decided that for incident recording, a high frame rate is likely more important than high resolution. My dashcam can only do 4K at 30fps so I have it set to 2K60." and he says he uses Vantrue X4.
 
It is called downscaling and just need to bunch up 4 pixels to behave as 1 pixel. 1k-2k-4k-8k, each ups pixels by 4x
That's the problem, making 4 pixels out of 4k to 1 pixel means 1080p.., on the other side 1440p is made out of 4x720p. Transition between them (4k vs 2k) is a bit more complicated and without proper handling (in most cases means power/instructions sets which are not available for mere ARM based, power effective dashcams) can result in rather worse output.

Have you ever seen 1080p/4k video on 1440p display or 1440p video on 1080p/4k display?
 
That's the problem, making 4 pixels out of 4k to 1 pixel means 1080p.., on the other side 1440p is made out of 4x720p. Transition between them (4k vs 2k) is a bit more complicated and without proper handling (in most cases means power/instructions sets which are not available for mere ARM based, power effective dashcams) can result in rather worse output.

Have you ever seen 1080p/4k video on 1440p display or 1440p video on 1080p/4k display?
Right, so the solution is to make do with 1080 and all is good, 2K is only slightly bigger than 1080, right? :)

So is there an option to down it to 2k for 60fps in settings?
 
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In case you want 60fps with the same FoV yes, the result 1080p video will most likely look clearer than somehow down/upscaled 2k. But then why not buy 1080p camera right away with larger pixels and therefore higher light sensitivity...

The point is it's not that easy and not everytime "others have it" means it's better. :) Not using native resolution in most cases is no good.
 
If going to a lower resolution in a dashcam meant that there would be pixel binning going on, then yes i would consider it, but if you just use lesser of the sensors pixels to make up a lesser resolution, then in that case i would stay with the native resolution.
60 FPS i care not for ( in a dashcam )
 
Right, so the solution is to make do with 1080 and all is good, 2K is only slightly bigger than 1080, right? :)

So is there an option to down it to 2k for 60fps in settings?
2K has 2x the number of pixels as 1080, 4K has 2x the number of pixels as 2K (4x 1080).
So you get twice the detail in 2K compared to 1080, and four times the detail in 4K.

To convert from 4K to 1080 is easy, you just combine every 2x2 block of pixels (4 pixels) into 1, and you get a perfect result, with one quarter the detail, which is a big loss just to get twice the frame rate, when you probably don't need the extra frames.

To convert 4K into 2K you just drop 1 out of every 3 columns of pixels and 1 out of every 3 rows of pixels, another easy conversion to do, and you end up with half the detail, which can still be a significant loss but not nearly as bad as losing three quarters of the detail. There is a side effect that diagonal lines become a bit jagged, but that is not too bad for evidence purposes.

Most people seem pretty happy with the conversion from 4K to 2K, watching on a 4K TV screen many people don't have good enough eyes to see the difference, but there is a loss of detail. It is not just Vantrue that can do it, Viofo also do it on their 4K camera, but the Viofo camera can record in much higher bitrate so records more information, so the loss of detail is more noticable. If you are using a low bitrate 4K camera, such as Blackvue then you quite likely won't notice the difference even if you have good eyes and a big screen!

My recommendation is to stick to 30 fps if your video is for use as evidence, you very rarely catch things at 60fps that are not also caught at 30fps when you have 4K. With 1080, because the resolution is a quarter, you can't see nearly as far, so there is far less chance of catching things. If you record in 1080 from a 4K sensor, you are roughly halving the distance at which you can see a plate, halving the number of frames that record the plate, so canceling out the increase to 60fps, while also more than doubling the amount of motion blur, which is often what actually stops you reading a plate in 1080 resolution!
 
In case you want 60fps with the same FoV yes, the result 1080p video will most likely look clearer than somehow down/upscaled 2k. But then why not buy 1080p camera right away with larger pixels and therefore higher light sensitivity...

The point is it's not that easy and not everytime "others have it" means it's better. :) Not using native resolution in most cases is no good.
I'm just trying to find a dashcam that can do everything I need from it. The global 4G LTE supports band B1,B3,B7,B20 which obviously lacks B8, B28 and B40 for Optus. The AU version only goes with Vodafone of which I do not touch.

I do not want the second box LTE version, just the inbuilt ones. At first I thought that 4K would have LTE built in which was why I was asking about the resolution as I just wanted 1080 instead of 4k but to also have the option of internet connection in the car via LTE of which I can also use to surf the web and the such. Upon closer checking, it does not have it, only via the second box for LTE, so no beuno!

Would be nice to have a dashcam that can do 1080 or 2k at 60fps, have inbuilt LTE 5G (will make do with 4G) that supports my mobile phone company's bands providing internet for both the dashcam and for any other things such as tablets to connect and surf the web in the car, that also turns off when I have the car off and not in park mode and comes on when I start the car. Able to set up geofences around home and the workplace car park and set park mode inside these geo fences to "disabled" and all places outside that to "enabled".

Mostly a thing of getting a lot of things automated and filling multiply needs with the least hassle. Will have to make do with using phone hotspot for internet for now.

Edit: Yes you can surf the web via Blackvue LTE
 
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I'm just trying to find a dashcam that can do everything I need from it

Aren't we all? But rarely can you have everything, at least not to the degree you'd like. Every dashcam is a compromise, so the trick is to have the compromise(s) in the least important areas ;) For most of us, best vid details is what is paramount; lacking that compromises everything else downstream. Using the native resolution of a sensor is where best vids possibilities begin :cool: From there it's FW and what the FW allows you to do.

Blackvue seems to put connectivity first, Thinkware seems to put overall technology first, and Viofo puts vid quality first. Other cams do part of what these can do but not all of it. Just have to do the best you can with what's out there :whistle:

Phil
 
To answer my original question, no you cannot change resolution, even if it is exactly 1/4 for binning.
 
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