[FFmpeg-user] Extracting frames from 59.94 FPS video - only every other frame is different

[Andy Furniss]

Andy Furniss wrote:
> Will Price wrote:
>> Hello,
>>
>> I'm having a strange problem when extracting frames from a video 
>> recorded from a GoPro HERO 5 Black camera (1080p, 60FPS, Linear FOV). 
>> When I view the extracted frames it appears that every two frames is a 
>> duplicate of one another, i.e. frames 1 and 2 look the same, frame 3 
>> shows a change, but frame 4 again looks the same as 3.
> 
> Only sometimes - there are also runs of different frames.
> 
>> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x55c3a7e709c0] Using non-standard frame 
>> rate 59/1
> 
> Maybe something to do with this.

Though playing the vid that may just be a distraction.

Looks like the early part is duped but the later part mostly isn't.

Maybe it's intended by the camera eg. the early part is lower motion or 
lower light level.

Either could be a factor - you could experiment taking other scenes 
varying motion or light levels and see if there is a pattern.