I suspect someone copied and pasted rather than doing the maths, and the rather low bitrate for the 1600 can be improved, assuming it is correctly recorded...
Possibly...
I see that there seems to be a hard-coded total limit of
55-58Mbps among all the cameras when running in 3CH regardless of whether 1600P or 2100P resolution.
There is a hard-coded total limit of
60Mbps in 2CH mode at 2100P resolution.
Given the above, I don't see any valid reason as to why there should be a hard coded total limit of only
44Mbps in 2CH mode at 1600P resolution. They should have room to increase the front camera bitrate in 2CH mode to at least 44Mbps at 1600P resolution (okay...now I see where the mistake could have come from) 44Mbps+16Mbps = 60Mbps. The Viofo firmware intern may have used 44Mbps for the "total" camera output to do their back of envelope calculations rather than a total output of 60Mbps which is likely what was supposed to be used.
If this is not an error at all and it is indeed intentional, then it does not make a lick of sense to run at 1600P in 2CH mode.
So the more interesting comparison for me in 2CH mode would be:
3840x
2100 = 8,064,000 pixels
2K 1440P (2560x
1440) = 3,686,400 pixels
3840x
2100 = 44.86Mbps bitrate for the front camera in 2CH mode
2K 1440P (2560x
1440) = 58.46Mbps bitrate!!! for the front camera in 2CH mode at this resolution while having to display only half of the total pixels which seems out of this world
π
Much more bitrates to use while having to display less resolution (or half the number of pixels) should be a massive increase in IQ quality.
Hoping to see an original (without YouTube compression preferred) head to head (side by side) video match-up at some point of the A139 Pro (4K 2100P 44.86Mbps
vs 2K 58.46Mbps) both day and night with HDR, but I know that is asking for too much as it is unlikely that any reviewer here has 2 front/rear camera units of the A139 Pro.
The image quality is surprisingly good at lower bitrates though, I'm not sure that everyone will want to run it set to maximum bitrate all the time, sometimes more recording time, or more reliability from the memory card is preferable.
Doesn't apply to me as I always run the maximum bitrate on any camera that I use all the time. If I'm spending that much money on it, why not?
If I want more recording, I would get a bigger SD card.
Reliability? I would stick with SanDisk MAX Endurance or the Viofo branded memory card and nothing else. I have some spares that I can use while I deal with the RMA of any memory card that fails.