GH4 video judder/strobing - a solution

Quarkar wrote:

Hi,

I am not new to these forums, have been visiting for quite some time now. Soaking up this vast knowledge from many of you wonderful and super helpful people. Thank you so much for all your hard work, greatly appreciated.

I've decided to sign up and make a user account on DPreview, just because of this thread. This will be kind of lengthy first post, but I wanted to share my experience. While I do understand it's and old thread now, I still don't believe it's old issue with this judder/strobe problem. There is still a lot of GH4 users fighting with same problem, including myself.

However, I believe I finally solved my problem with this. I've noticed some people said with 100% certainty, it's not computer system problem, their machines are really powerful and so on... I was on that train too, I believed my machine is powerful enough to allow me to deal with 4K in best way possible... boy, was I wrong. This is my configuration (at least what's important in this case):

• Video card: Nvidia GeForce GTX 760 - 2Gb, GDDR5, PCI-Express 2.0 (x16)
• Processor: Intel Core i5-3570K - Quad Core, 6MB L3 Cache, 3.40GHz (3.80GHz Max Turbo), Unlocked
• Motherboard: GIGABYTE GA-Z77X-UD3H Intel 7 Series Motherboard
• Memory: Kingston HyperX Blu 16GB Desktop Memory Module Kit - DDR3, 1600MHz
• Power Supply: Corsair Enthusiast Series TX750 V2 - 750 Watts
• Hard Drives: Seagate Barracuda ST2000DM001 2TB Serial ATA Hard Drive - 2TB, 7200RPM, 64MB, SATA 6Gb + WD 2TB + 4 external backup HDs
• CPU Cooler: Cooler Master Hyper 212 EVO Direct Heat Pipe CPU Cooler R2
• BENQ G2420HD 24" 60Hz monitor

Like many others already mentioned, I've had nothing but trouble with 24 fps footage (I am in North America, NTSC), and its at that point to me looked like, unavoidable judder... even when my camera was completely static on a tripod, and I had my daughter riding her scateboard and passing close to camera. There was unbelievable amount of judder, can't even explain properly what it is... flicker on her when she was passing by. Almost like it was taken with super fast shutter speed, but it was obviously different. It's hard to explain really. Now, I always tend to use 180 degree shutter angle, and that always worked the best for me.

Today, I took 18 tests, all the recording modes I am interested in (4K, 1080p, 200 Mbps, 100Mbps, 24fps, 30 fps, 60 fps, tried 59.94 Hz (NTSC) as system frequency, as well as 24 (CINEMA) etc). I had exactly the same subject, my bed frame with vertical bars, and child safety gate with circular holes in it... really just something quickly so I can test it. I also have a fluid ball head tripod and slider/dolly, so I tried making a pan in all cases exactly the same speed.

Results... regardless of how slow I was panning, that nasty judder was always there while shooting 4K 24 fps. All other resolutions were perfectly smooth, even 4K 30 fps, not to mention how smooth is 1080p 30 and 60 fps. Well, I got that nasty judder in 4K, 24 fps at least on my monitor (BENQ G2420HD 24"), while it looked perfectly fine on my GH4 LCD. That made me think...

This afternoon, I took all my test footage, non-edited, in its original untouched form, saved to my portable HD directly from camera, and tried playing it here at work. Here I have almost identical PC configuration, except I have i7 processor instead of the i5 I have at home. So machine at work is little faster. It appears, just enough to make incredible difference. At least for me.

Result: Every single 4K footage in 24 fps I brought here, that had so much judder/flicker on moving objects, magically disappeared in a split of second. My 4K, 24 fps footage was amazingly smooth, well as much as 24 fps can look smooth, we know there always will be that flip-book/film kind of effect, but isn't that the point of using 24 fps anyway? Judder/flicker completely disappeared. Not that it was little nicer comparing to how it played on my home machine, but it was rather drastic 180 degree situation. Judder completely GONE. Before, I even though something is wrong with my GH4, but when I tried my friend's GH4, we've got exactly the same results.

Now, at least I can breathe easily I know it's not problem with my camera. That's why Panasonic "is not doing anything to fix it". There is nothing to fix it actually. Again, I was among all those who always claimed: "...oh, I'm pretty sure my machine is more than powerful to run 4K...", but I admit - I was dead wrong.

I can finally go back to shooting with my GH4 without thinking something is wrong with it.

Oh yes, forgot to mention, at work I have different monitor too. Some old Philips LCD 244E which should not make any difference, it's still 24" and 60 Hz.

So for all those who are still experiencing the same judder trouble, please try "affected" footage on some more powerful computer just for testing purposes. You'll see amazing difference. It changed my perspective completely on this whole problem. Also, I know that some newer monitors have some options to add/remove motion blur and they have some kind of hardware compensation involved. In some cases, that can do more harm than good as well.

Hope this can help someone in future, someone who's banging their head against the wall because of this judder. I solved mine. It was actually never there, I simply used under-powered machine to view my files.

Cheers!

My experience still stands true to me, it's the monitor.

Your work-place Philips 244E has variable frequency refresh, 56–75 Hz (V)

- one of it's features is its also tailored for viewing DVD films - which play at 24fps (the monitor will automatically run at 72Hz (exactly 3 refresh cycles per frame).

Your home monitor may be fixed at 60 Hz (as most computer LCDs are), it will judder with 24fps footage, but will be smooth with 30fps (exactly 2 refresh cycles per frame).