GH4 GH4 Slowmo

B

Boon

Well-known member
For 50 fps slow-motion, any difference in quality between using Variable Frame Rate 50 and 1080 50p reinterpret to 25p in NLE?

thanks
 
VFR is doing something odd to the footage for us. I mean its not bad but a little softer. Normal 50/60p is just as good as normal 24/25p filming.
 
FPS override is giving 24mbps files. 1080-50p you get 100mbps. It's over 4 times the bitrate and significantly better image quality.

With that said, I don't believe there is a camera of this type made that will film at these high frame rates and output a file in the slow motion in 30p or 24p in camera. It's an amazing tool to see your slowmotion on screen right then and there. It freaks people out to instantly play back the scene in slowmo like that. The fact that you don't have to go to post to slow things down is incredibly useful.

Cheers,
Pete
 
c3hammer said:
FPS override is giving 24mbps files. 1080-50p you get 100mbps. It's over 4 times the bitrate and significantly better image quality.
Click to expand...

The bitrate is the same, it's just that the VFR clips are already conformed, which stretches your bitrate out. 100Mbps stretched out to 25% speed = 25Mbps.
 
aldolega said:
The bitrate is the same, it's just that the VFR clips are already conformed, which stretches your bitrate out. 100Mbps stretched out to 25% speed = 25Mbps.
Click to expand...
So you are correct it's not 4 times, but we still get double the bit rate when using 50p at 100mbps. Shooting in 50p gives a cleaner image. It's quite clear the difference.

Cheers,
Pete
 
You get double the bitrate as what? Shooting 25p? The same thing is happening- 50p is twice as fast as 25p.

And it's been established that the IQ goes down a bit over 60p (or perhaps over 50p in PAL mode)- a bit softer and some aliasing and moiré. That doesn't have to do with the bitrate, though. The camera probably has to switch to a cruder binning process to run that fast.
 
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