8-Bit Issue

F

FelixGER

Well-known member
Hi,

I´m wondering if the FS100 picture will suffer from 8-bit encoding exactly as every consumer camcorder, DSLR or is there some advanced technique to surpress color banding, solarization on solid colors like walls or the sky?

All the footage I watched is from youtube/vimeo which is so heavily compressed you couldn´t tell if it´s in the source footage.
 
Yes it is 8-bit, as for the implementation and processing, it's unlikely we'll know its performance until it is in people's hands. Personally I have never been very bothered by 8-bit recording. Occasionally a camera will perform poorly in its bit depth downconversion. I do not know how implementations differ, whether there are some that apply various degrees of dithering or some that apply none at all. In many cases, issues with banding/posterization may result less from the inherent limitations of 8bit recording and more from gamma and picture corrections applied in camera. This is why some people prefer log, there is less chance of any particular range of the sensor response that might be more susceptible to banding, but a properly implemented gamma curve should go a long way toward avoiding such artifacts by not overly compressing any part of the luma range.

Are there particular consumer camcorders you are referring to that have a particularly noticeable issue?
 
I don't have a big problem with it either, except where grading is concerned. I think 8 bit will really limit options there.
 
Yeah, 8bit is not exactly great, but if you record to an external recorder to a good codec, or even uncompressed it is not gonna be such a big deal.
I graded even super lossy 4:2.0 5DII material with success (to some degree-but ya gotta be a bit careful)

But we have to wait and see, when the first production models are out.
I´m sure there is a lot that can be done in the firmware also.

Maybe Vitaly or an other programming guru jumps on it and we soon have S-log out of the HDMI :happy:


Frank
 
Is it something that in your experience with your GH2 only shows up after grading, or is it noticeable in the originals? To show it better, always better to export something uncompressed or lossless like tif or lossless png.

One thing to consider, is that while there will always be limitations of 8bit recording, but you might be surprised how easy it is to hide even heavy banding with just a little film grain or noise to dither the image a bit, this is not always appropriate though and it also can be much more taxing on encoders. It is important to also make sure any image/video processing app is processing your 8bit images at higher bit depth in memory so that bits are not wasted in following generations of your video material. It's hard to say about the Gh2 vs the FS100, I also have a GH2 and am buying an FS100. The Gh2 is unusually good at some things, but it is still a very small form factor multi-fuction camera and still probably really a stills camera before it is a camcorder. I guess we will soon see how it compares.
 
Hidef1080 said:
For a minute I thought that was JJ Abrams.

What am I looking for in the photo?
Click to expand...

Color banding everywhere especially on the white solid to the right.
Camera was on smooth everything -2. It´s not the grading (Just some minor 3-way CC and a soft s-curve. It´s also in the ungraded footage.

But let´s not discuss the GH2. Question is, if the FS100 will do it better than that.
 
FelixGER said:
Yep, GH2.
That´s a screencap of my recent short movie. You can´t see it that ugly in the moving picture. Vegas jpeg export seems to "amplifie" the problem, but it´s about 40% that bad.
http://www.imagebanana.com/view/3sn2j969/Bild10.jpg
Click to expand...

The banding reported on the AF100 and GH2 relates to that sensor and/or processing, and isn't an 8 bit issue.

Ever heard about banding complaints on an EX1 or EX3? Ever heard of banding complaints with the HVX200? And never, not once, have I had banding issues on the HPX170 or HMC150 (same codec as the AF100).

I'll bet you the shiny black Mercedes in my driveway that you're not going to get the same banding complaints with the FS100 (or anything else 8 bit) that you're getting out of the AF100 and similar sensor Panasonics.
 
We will only know when we can play with the camera and test it on the sky, or on situations like you've created. I've seen AF100 to EX1 comparisons done and the EX1 didn't have the same banding as the AF100. After going in and looking closer, I saw that the EX1 had a dithered approach to these types of situations whereas the AF100 gradients had steps. To deal with this, I let a bit of the noise back in to my AF100 by way of the detail setting (so basically, just amplifying the noise a little) as it looked like subtle grain and it allowed the edges of most gradients like this to dither.

In theory, given the displays people typically use to edit or view video are 8-bit already, you should be able with 8-bit to get exactly the same results. That said, if I create a gradient in photoshop and make it big enough, I get banding on my 8-bit displays. Therefore, what I believe is that the magic that comes from these cameras is the downsample. Given most sensors are 12-bit or higher, that conversion down to 8-bit REALLY would benefit from using a dithered method. In addition, with my experimentation of H.264 encoding, this can (just as JPG did for you) expand the banding issues even worse.

So in summary, 8-bit is not the issue, it's the conversion down to 8-bit and how well that is done. I can certainly test this for you when I get my camera at the end of the month. As I am curious as well! :)
 
AGMedia said:
The banding reported on the AF100 and GH2 relates to that sensor and/or processing, and isn't an 8 bit issue.

Ever heard about banding complaints on an EX1 or EX3? Ever heard of banding complaints with the HVX200? And never, not once, have I had banding issues on the HPX170 or HMC150 (same codec as the AF100).

I'll bet you the shiny black Mercedes in my driveway that you're not going to get the same banding complaints with the FS100 (or anything else 8 bit) that you're getting out of the AF100 and similar sensor Panasonics.
Click to expand...


thank you.

you can't compare a gh2 or af100 to the fs100 simply because they are both 8 bit. look at ex1 footage which is 8 bit 4:2:0. you can make the banding show up but only under the most brutal conditions such as a frame filled with gradient sky, etc. i believe that the fs100 recorded externally to prores 4:2:2 will be solid. and while it's still 8 bit footage in a 10 bit container, will grade beautifully. example, footage shot on ex1 in 4:2:0 xdcam ex format, then converted to prores, looks great. so skipping the xdcam codec and the 4:2:0 color downgrade, must produce even better results.
 
I know, it´s way to early, but I wonder what can be done in firmware.
I mean, the F3 spits out S-Log just with just an software update, but all the hardware you need is already there.
Who knows what the FS100 hardware could do, if one writes his own firmware.

Frank
 
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