05-26-2021 09:35 AM
Specific question about HDMI & framerate on Hero 3+ Silver[ New ]
I am facing this strange behaviour with my Hero3+ Silver, when connecting to a 1080i50 device
The camera is set to record 1080p25, so I assumed that when outputting to HDMI 1080i50 the result would be equivalent to 1080PsF50, hence require NO deinterlacing if further processed as progressive (this is what happens when I set other camcorder to film 1080p25 and connect to HDMI as 1080i50)
A first test at home confirmed that there were no visible interlacing artefacts, confirming the above assumption.
But later, while recording a live session for streaming, I realized that the recorded video (downscaled to 720p25) showed very visible interlacing artefacts just for the Hero3 parts, NOT for the other cameras.
Why would a Hero3+ send sometimes 50fps true interlaced video, and sometimes 50 PsF, when configured for p25 recording ?
Could it be that in low light condition, the shutter is effectively set to 1/25 and hence, sending apparent 25p over i50 which is PsF, while in brighter light conditions, the shutter automatically goes to higher values (1/50 or more), sending 50fps over HDMI (which results in 50i in this case, as the receiver HDMI side doesn't do 50p) despite being internally recording at p25 as configured ????