Vesku

GH4 graphic card or main board broken ?

One way to get better Youtube IQ is to render 1440 or even 2160 version of your video. When browser downscales it to monitor size (normally fullhd) it looks much cleaner.

It is quite confusing for many if Googling video levels. That video is super sharp and it does not play smooth in my computer. Is it somehow 4k in vimeo and browser is scaling it to my fullhd monitor. You can render and sharpen GH4 4k as sharp as you want when converting to 2k.

I mostly just watch my videos, I dont edit much. Dont you first watch or preview or organize your clips before you edit? Would it be nice if you see those clips the way they are shooted, not with clipped whites and blacks.

This test is done in 4k. GH4 autofocuses very slowly in 4k and autofocus in 4k is generally not a good idea. Result may be different in 2k.

Lets think that GH4 0-255 is like "8bit RAW" camera. When you grade to 0-100 IRE you are compressing colors to 16-235 (normal video levels). Then you have a final program with proper and legas colors. If you want to watch that original GH4 0-255 "RAW" video and see all these 256 levels you must set your player or video card to limited range (16-235). The computer is still not limiting your video levels, it only passes all those 0-255 directly to your monitor and you see it right. It is kind of confusing because the full range setting is actually limiting GH4 0-255 levels in monitor and the limited setting is not limiting GH4 0-255 levels. If you watch GH4 "RAW" 0-255 without any settings you loose 16 black and 20 white level because video players and video cards has default settings for normal 16-235 video. GH4 wider range of levels just spill over the edges. Some players may have auto levels function and with it you may see all the levels. With Potplayer auto levels I still cant see the exact result, it is about right but not completely. Some day we wont need this old limited 16-235 video standard and we can use 0-255 scale like with photos. Today some systems use and show 0-255 properly and some systems understand only 16-235. Then there are superwhites 235-255, blacker than black etc...

I made a color corrected example of that YT video (one frame). Dyn range is just OK. http://***URL removed***/forums/post/54891515

I solved the levels issue for me. I compared the original GH4 0-255 video source frame and the same frame captured from monitor after output level adjustment 16-235 in Potplayer and video card full range 0-255 mode. I studied the frames in Photoshop and those are absolutely identical, no IQ loss or level conversion. It is quite disturbing and against common sense to set video output to limited range 16-235 before sending it to video card. The Potplayer has a floating level space and when using a limited output range it actually sends the right levels to video card and monitor. Nothing is lost. So I use in Potplayer level settings input (source) 0-255 and output 16-235 and video card full scale 0-255. Then I see all the original GH4 0-255 levels right in my monitor. I can have the same effect by selecting a limited range (16-235) in video card and leaving levels untouched in player. The practical thing with Potplayer is that I can alter levels if I want to enhance levels while playing files or if watching different cameras which has different levels. GH2 for example records 16-255.

Yes it is. If you downscale those JPG photos 4.6k to 3.8k the IQ is much better than 4k video. If you speed up some landscape or city lights video it is not looking odd. Have you seen my tests? http://***URL removed***/forums/post/54879969 http://***URL removed***/forums/post/54879969

Yes, if you use normal legal standard video the levels in the video file are 16-235. If you watch that file with a standard TV or AV monitor it shows these values right as black and white. If you use a computer monitor the video card expands these 16-235 levels to monitor RGB 0-255. You have actually 220 shades but the computer (player, editor,video card) converts it to 256 shades and the quality is not the same as i.e. 0-255 photos or videos. GH4 can record video as illegal or non-standard 0-255 levels (all YUV channels) and it in theory records more information than a normal video. It is like "poor mans RAW". When color correcting and rendering the final standard 16-235 video there is more information to adjust. My issue is how can I see all the original 0-255 levels with a computer monitor without any converting.

GH3/GH4 has not the best sensor sampling at fullhd. Sony RX10 or Sony A7s or some camcorder may have a little cleaner image in 1080/60P in a static clip. GH3 and especially GH4 has still the best codecs (less artefacts, 0-255) so the final result is very good, maybe the best after all.

It is also a way to shoot 5k video with full sensor (wider image). Should be very nice for landscape panning or fast moving cloud shots. If using JPGs the recording time is no issue and when downsampling to 3840 the IQ is much better than with normal 4k.

I am using GH4 video 0-255 luminance levels. It is quite confusing because some players shows only normal 16-235 levels and some editors does not use 0-255 properly. Some say 16-235 is better for codec (less information to process- more bitrate to details) etc etc. Graphic cards has full range/limited range (16-235) settings... If I watch my GH4 0-255 videos with Potplayer I must set in levels settings: input 0-255, output 16-235 to see all details in highs and lows. Why must I use output 16-235 while my monitor is still 0-255 RGB monitor? The logical way should be input 0-255 and output 0-255. Is the video signal always finally 16-235? Is there any benefits of using 0-255 in camera? How a player or editor changes YUV signal to RGB?

I can see pixels in fullhd videos at fullhd monitor. is that estethically good. I want to see the image behind pixels:)

Post panning across 4k image is a new way to show scene. Does it have to look the same as a real camera pan? Which looks better? Must it always be the old way?

I shooted a test chart with 4k, JPG and RAW. The 100% sensor center area is the same in all these images - 4k 100Mbs, JPG best quality and RAW ACR conversion. 4k and JPG are very close to each other, RAW is much cleaner. I found also that GH4 RAW has less resolution in colorful parts than in gray parts due to sensor de-bayering. GH4 4k video is very good and very close to cropped 8 Mpixel JPG photo. I thought 4:2:0 video codec would ruin colors compared to JPG but no. I think GH4 JPG is 4:2:2. RAW is 4:4:4 I doubt if there is any color benefits of using external 4:2:2 recording because JPG photo is not better than 4k. http://***URL removed***/forums/post/54879969

GH4 4:2:0 4k is very close to photo JPG and even RAW photo quality (3840pix center crop). Still RAW is far from perfect due to de-bayering. http://***URL removed***/forums/post/54879969

Is the NX1 4k sharper than GH4? It should be much cleaner because of 6.5k to 3.8k downsampling.

Has anyone tried if there any significant benefit of using 4k 10bit 4:2:2 with GH4 compared to internal recording? The sensor is not very good at 100% readout and if it is 2/3 of true resolution can we see the benefit of better color sampling?

4k is fine and very welcome. De-bayering is still destroying 100% sensor colors even in RAW photos. My GH4 raw photos at 100% looks like perfect 4:2:0 video. Pure colors has less resolution than other parts. Is it then very important to get an external recorder because the RAW sensor data is already noisy and gives unperfect colors? NX1 colors may be much cleaner due to 6.5k to 3.8k sensor downscale.

If the sensor debayering is so bad is there any difference in 4:4:4 vs 4:2:0 at 100% sensor image?

There are lots of GH4 videos online. Just study them. Rolling shutter is not a problem if not moving camera too much or shooting passing trains.

I made GH4 100% sensor readout test with different modes: http://***URL removed***/forums/post/54849358 1. 4k center crop 2. 4k 2x dig zoom downsampled to fullhd 3. ETC fullhd 4. best JPG center crop 1920x1080 5. RAW (ACR) center crop 1920x1080

A (video) is indeed overcontrasty and oversaturated. Not at all watercolor look. I think that GH4 4k can render more natural look. But sharpness and clean colors - I dont know...