Yes, there really isn't a whole lot to get excited about just yet. It's still a lot of wishful thinking. I'd much rather just get a camera that shoots real raw, personally. I still have to be skeptical about a process that's going to work really hard to give a shooter something the camera should have been designed to give them in the first place. 420 and compressed 422 in 2014...they should be ashamed of themselves. I'm pulling for all the disruptive cameras from not Panasonic, not Sony, not Canon to not only erode the sales of these things but ultimately generate a lot of buyer's remorse.

@AdamT the consensus is the math is true for recovering 10bits of luma after the re-sample+resize. You're not going to get a true 10bits in chroma, as good as if you'd shot with a camera that actually shot 10bit 444 in your target resolution but it should be "better". The method of re-sampling will play into how much better. This particular method is the simplest and offers the least return for the effort in its current form but it offers a lot of convenience over the hassle of getting similar results in a full-blown application (which aren't going to offer markedly better results than this little command line tool).

There's another thread here discussing the Windmotion package which works in the opposite way, believe it or not, taking 1080P and arriving at cleverly resampled, higher resolution results. The techniques employed there, both spatial and temporal, offer a more evolved path than this simpler proof-of-concept. For something like this to really sing there's going to have to be a temporal component. It's going to have to be more than just trading spatial resolution for slightly higher quality pixels.

@Vitaliy Yep agreed, there is a market there for sure! If there is already a basic code app that converts GH4 4K footage to 1080P 4:4:4 at the Mac terminal and the GH4 hasn't even been released yet, then I am sure there will be plenty of apps that will do this kind of thing for GH4 footage after it's been out a little while. It almost certainly will be a very big selling camera and there will be a lot of 3rd party apps that will surface for it. Time will tell.

If you look back you'll see me mentioning that with GH4 release we'll see multiple such tools.
This is just first bare attempt to make simplest thing possible.

I don't have a Mac or recognizale math skills so ... does this make sense to anyone?

http://www.eoshd.com/content/12594/exclusive-first-app-resample-panasonic-gh4-4k-8bit-10bit-444

Unfortunately, I'm not, currently. My technical expertise rarely goes beyond Houdini VEX and shading language. But I know people who are. I've never heard of any kind of stochastic technique being previously employed for re-sizing and, in practice, most of the current techniques seem to preserve many of the defects you'd be hoping would just go away in this particular situation.

This would possibly avoid the necessity of doing a second step of either synthetic or image/scan-based "cover up" noise. Of course, it might not work either. Going from 4K to 1080P might not offer enough of a jump to really get it good but I'm still curious.

I'd like to see a re-sizing and re-sampling scheme that used poisson disc sampling to not only take care of the "dithering" needed to keep 4K 8bit skies from still banding once 2K or 1080P but have the added benefit of better approximating organic imagery in a way that direct sampling from any fixed grid sensor never will.

Lots of GH4 samples over there and nobody is getting 10bit color from a 4k 8bit file. Maybe you guys should teach them how to do it properly. I also did my try and got tipical 8bit banding while trying to grade a "magical 1080 444 10 bit" from a 4k 420 8bit.

OK @tosvus, I'm not a programmer, but I know how a 10 bit footage behave in post, I work with that from several years. Believe me, your math isnt wrong, but lack of more parameters. I recommend reading other forums that I'm not allowed to link here, I may not use the right words to say how it works properly. Anyway, lets wait for the GH4 and hope for a good processing.

@tosvus but to avoid loses, the GH4 must have a nice picture profile, with maximum expanded DR. I mean going to the limits. Because the camera processing could retrieve all the DR while still RAW, before going into a flat 8bit file. After become 8bit, there is not too much to do. See, for example: a highlight in the sky. Even if the camera get a nice code to pickup these 4 8bit pixels into one 10bit pixel, these 4 pixels already would be white, 4 white 8bit pixels going into onde 10bit pixel. So what the meaning of more pixels if these pixels would be all cliped highlights? Native 10bit has more room before these white become a dead flat white.

@tosvus - If someone writes a transcoding utility that has the conversion accuracy you describe, along with the option of producing either dnxhd or pro-res at the end of it, you would have some very happy campers

@tosvus 10bit isnt only color, it holds more DR too. The theory you guys are talking is right, but only to get smoother color gradation. 10bit is much more than that. Once encoded into 8bit all the whites and blacks become flat white and flat black. You can have a 10k resolution file in 8bit, the whites and black are already flat and all the possible tonality behind them are already washed out, no matter downscale to 10 or 14bit. I'm not talking about color here, I'm talking about the full power of true 10bit. And 10bit holds much more DR than 8bit. Color you can smooth by mixing adjacent pixels of a larger resolution to improove the gradation when downscaled into a 10bit file. But DR once become flat cannot be retrieved.

OK. Keep dreaming you can retrieve dead DR from any resolution (4k 5k 6k...) at 8bit downscaled to 2k at 10bit. Lol... Maybe you math guys never worked before with 10bit video. You can retrieve black'n whites pushing the latitude in post.