I have recorded the flight subtitles in my videos (*.srt) and would like to know what ABS_ALT refers to.
I thought it could be the altitude of the drone in relation to the takeoff but I'm starting to think that maybe it could be the altitude in relation to the determined for RTH.
Could someone clear my doubt?

Honestly i have always deaktivated the subtext, but if i take this example: [rel_alt: 17.000 abs_alt: 116608856.000]

rel_alt:  relative hight in relation to the homepoint
abs_alt: total hight calculation by airpressure in relation  above sea level.

MySky Posted at 6-27 10:59
Honestly i have always deaktivated the subtext, but if i take this example: [rel_alt: 17.000 abs_alt: 116608856.000]

rel_alt:  relative hight in relation to the homepoint

Thanks for clarifying.`

I find it very interesting to keep the subtext because it helps me not to forget the best PRO setting (considering that I do some ISO+EXP tests) that I did in several takes of the same location/time

MySky Posted at 2022-6-27 10:59
Honestly i have always deaktivated the subtext, but if i take this example: [rel_alt: 17.000 abs_alt: 116608856.000]

rel_alt:  relative hight in relation to the homepoint

abs_alt: total hight calculation by airpressure in relation  above sea level.   


Sounds like your attempting to describe Pressure Altitude?  Pressure Alt is the altitude at sea level in standard atmospheric conditions which is a pressure of 14.7 psi also calculated in inches of mercury at 29.9" at standard temperatures of 15* C/ 59*F.  This is a theoretical datum plane to which atmospheric conditions are relative to.  The drone would need either a mechanical or digital altimeter which is calibrated to calculate pressure of the air around the drone relative to the standard pressure of 29.9 at sea level to know what pressure altitude it is at.  Atmospheric pressure changes constantly regardless if a change in altitude.  also the higher up in altitude an aircraft is the LOWER the atmospheric pressure around it.  the altimeter that is calibrated at sea level of 29.9" calculates the difference of these two pressures and converts it to feet.  For every 1000' altitude gain the pressure drops 1" of mercury.

I do not think ABS ALT stands for Pressure Altitude.  I have a flight where my ABS ALT is 763' but my drone is returning to home at default 164' REL ALT.  My location/Home point is at 1800" MSL which stands for mean sea level, the altitude above sea level.
It certainly isn't Absolute Altitude either since the drone does not have a radar altimeter and would have to use GPS data to calculate this which it possibly could do.  Absolute altitude is the altitude above the ground AKA AGL (above ground level)  
I'm curious to know what Alt my drone was flying at and what the ABS ALT of 763' stands for.  its not pressure altitude, not true altitude, not absolute/AGL, which only leave indicated altitude but this reading cant be it either because my "ABS ALT of 763' on a 88*F day although temperature is irrelevant for this topic,  (I do not know the QNH/barometric pressure at that time but I would estimate my drone to be flying at about 1978' MSL.  about 178' AGL. I launch from my deck which is 15' above the ground.

lol. That covers 90% of the altitudes in aviation.  I'm a pilot.  

fans02cb46b4 Posted at 9-6 14:59
abs_alt: total hight calculation by airpressure in relation  above sea level.   

Sounds like your attempting to describe Pressure Altitude?
DJI attempted to show Pressure Altitude, but their algorithm is flawed.
DJI failed to allow for the way air pressure varies and assumed standard air pressure.
As a result Absolute Altitude data gives very inaccurate numbers and is useless.
It is commonly +/- 200 feet and more from the actual altitude.
This example is 574 feet less than actual value and I've seen even greater.

Labroides Posted at 9-6 16:32
Sounds like your attempting to describe Pressure Altitude?
DJI attempted to show Pressure Altitude, but their algorithm is flawed.
DJI failed to allow for the way air pressure varies and assumed standard air pressure.

"DJI failed to allow for the way air pressure varies and assumed standard air pressure."

What else could DJI do but base everything on the std atmosphere. If you know of a way they could do otherwise please explain it, thanks.

Sean-bumble-bee Posted at 9-6 17:04
"DJI failed to allow for the way air pressure varies and assumed standard air pressure."

What else could DJI do but base everything on the std atmosphere. If you know of a way they could do otherwise please explain it, thanks.

Standard air pressure at sea level is 1013.2 millibars.
But actual air pressure can vary between 990-1030 millibars (and more in extreme weather)
By assuming air pressure is constant at 1013 millibars and not accounting for normal variation, the altitude DJI's formula will show is guaranteed to be variable and often show large errors, like the example I posted above.

Because the error is variable and  can be + or - the data cannot be corrected.
It's just useless.
It would be better if DJI did not give any Absolute Altitude data.