I bought a new YI action camera HWv 23L FW 1.5.6. and after a week of research came to useful results for Sunset Time Lapse.
Here are my findings.
1.) The YI camera does not adjust the exposure with Time Lapse interval 0.5 and 1s, so for the second phase of sunset we must use 2 or 5s interval.
2.) Flickering
If we use camera in full day light in auto exposure mode, we get horrible flicker. Here is graph of average pixel and shutter 10/____ value (I got it from the jpeg EXIF data) for 410 pictures Time Lapse with slowly changing light, so only 1 flicker appear.
detail 
And these is graph of 525 pictures long Sunset, starting at sun touchdown
and detail 
The EXIF data for the shutter is clearly the desired or required value, as determined by the auto exposure mechanism. Real shutter time is limited with the shutter resolution, which is (under my analyse) ~28 us. So at shutter time 1ms (10/10000) we get 2.8% of exposure and 1.26 % of RGB values step, which is good enough for Time Lapse
3.) My autoexec.ash
#Knee
t ia2 -adj autoknee 255
#ISO autoexposure gain
t ia2 -ae exp 100 Auto 0
#Auto WB off
t ia2 -awb off
#jpeg100
t cal -jqlt 100
#noise reduction
t ia2 -adj tidx -1 1 -1
#HDR
#t ia2 -adj l_expo 200
#EV correction -1EV
t ia2 -adj ae 64
Knee is set to maximum, so that the exposure adjusts as quickly as possible to the bright sky around the sun.
"t ia2 -adj l_expo 200" set a bit HDR picture, to get higher dynamic range and off course more noise. "t ia2 -adj gamma 200" do almost the same thing, but you lost saturation. We can try "t ia2 -adj l_expo 200" at sunsets with very high dynamics range (clear sky)
For sunset you must use "t ia2 -adj ae 64" to set exposure compensation to -1EV.
Here are my findings.
1.) The YI camera does not adjust the exposure with Time Lapse interval 0.5 and 1s, so for the second phase of sunset we must use 2 or 5s interval.
2.) Flickering
If we use camera in full day light in auto exposure mode, we get horrible flicker. Here is graph of average pixel and shutter 10/____ value (I got it from the jpeg EXIF data) for 410 pictures Time Lapse with slowly changing light, so only 1 flicker appear.
detail And these is graph of 525 pictures long Sunset, starting at sun touchdown
and detail The EXIF data for the shutter is clearly the desired or required value, as determined by the auto exposure mechanism. Real shutter time is limited with the shutter resolution, which is (under my analyse) ~28 us. So at shutter time 1ms (10/10000) we get 2.8% of exposure and 1.26 % of RGB values step, which is good enough for Time Lapse
3.) My autoexec.ash
#Knee
t ia2 -adj autoknee 255
#ISO autoexposure gain
t ia2 -ae exp 100 Auto 0
#Auto WB off
t ia2 -awb off
#jpeg100
t cal -jqlt 100
#noise reduction
t ia2 -adj tidx -1 1 -1
#HDR
#t ia2 -adj l_expo 200
#EV correction -1EV
t ia2 -adj ae 64
Knee is set to maximum, so that the exposure adjusts as quickly as possible to the bright sky around the sun.
"t ia2 -adj l_expo 200" set a bit HDR picture, to get higher dynamic range and off course more noise. "t ia2 -adj gamma 200" do almost the same thing, but you lost saturation. We can try "t ia2 -adj l_expo 200" at sunsets with very high dynamics range (clear sky)
For sunset you must use "t ia2 -adj ae 64" to set exposure compensation to -1EV.
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