GH4 video judder/strobing - a solution

Started Nov 15, 2014 | Discussions thread
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left eye
left eye Senior Member • Posts: 1,279
GH4 video judder/strobing - a solution
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Ok I'm a week into the GH4, and I've been battling with video judder / strobing, call it what you will. I had just about come to the conclusion that the GH4 is a techno gimmick, rather than a workhorse tool.

At 24fps, which gives access to C4K - that can be dropped into a 4K timeline to provide post panning options, or both into FHD, etc, so I've been using 24fps, + it gives that cinema look, right?

I just cannot get the GH4 to avoid the dreaded judder, I hear of people returning camera because of it, and going back to Canon!

The LCD monitor doesn't help either, as it's frequency is either 30 or 60 fps, ridiculous! why doesn't it just match the system freq! Anyway the judder many of us see goes beyond the LCD monitor, it's plaguing our recorded footage.

The judder isn't the classic slightly flick-book feel of 24fps, it's almost a judder every second or two, it's hard to put my finger on exactly the rate of judder, and it's more of flickery judder (rather than a dropped frame - which BTW there are no dropped frames); it's not an even 24fps flicker, though it's frequent and every now and again.

My workflow is 4K into a 1080 timeline, which as we all know with the GH4 is far superior to (same data-rate) 1080 captured footage.

The judder is most noticeable when panning - panning as slow & smoothly as possible, but also on moving subjects. Yes, I've been everywhere from 180 degrees shutter, to a soft 360 degrees; the judder just seems present where it wouldn't be with other gear running 24fps.

>>>

So what I did is set the camera frequency to 29.97 (NTSC) even though I live in a 25 (PAL) region. Now shooting 4K, dropped into a 1080 / 29.97 time-line, everything is buttery smooth, panning, zooming you name it. The weird thing is the difference is massive, suddenly I've got rock solid, smooth footage, not less judder or flicker, none!

It's not like the extra 6 fps has an incremental improvement on the problem (which as I say isn't 24fps flicker, it's occasional judder), the problem is no longer. Placing the same res 4K into a 1080 timeline, the footage the same 100Mbps data rate, surely rules out any computer performance issues, the only difference being the higher fps - which unlike the lower fps, plays without issue.

The computer BTW is a MacBook Pro 2.2 i7 quad core, 8GB DDR3, SSD drive, probably not the greatest of graphic cards, but it does have one (it does also have an on-board graphics chip, which I disable), it can handle 1080 fine.

It's almost as if the 24fps is interfering with something in the camera running at 23.97?

As a bonus the camera LCD is now also smooth and non-juddery, ok this doesn't effect the footage, but it's feedback builds confidence at the time of shooting.

As 29.97fps can be mastered / exported for Blu-Ray, are there any real issues in using 29.97 in Europe / PAL regions? Cinema projectors are traditionally 24fps (hence the C4K 24fps), though I believe now most cinema projectors can handle various frame rates. Can 29.97 / NTSC Blu-Rays be commercially distributed / sold in Europe?

My main issue with 29.97 would be if this prevents cinema projection - as this will be one destination for the footage; not nationwide, but specialist screenings (though in standard cinemas).

In any case 29.97 is quite a revelation on the GH4, whatever region you live in!

BTW is there any way to set the camera to 30fps? - and would that in any way be an advantage in term of distribution compatibility? I have no cause to use higher rates, such as 48fps or 60fps.

What are your thoughts on the subject, have you suffered from GH4 24fps judder, and found a solution? Most GH4 footage I have seen (Vimeo) is shot on a tripod with no panning! - which minimises the problem for sure, I wonder if this is because the judder is an issue (more than a total widespread preference for static angles!); generally though motion in the scenes seems fairly smooth.

I'd be glad to hear your experiences, and wisdom!

 left eye's gear list:left eye's gear list
Olympus E-300 Pentax K-5 Fujifilm GFX 50S Panasonic GH5 +5 more
Panasonic Lumix DMC-GH4
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