Converting 8bit UHD 8 4:2:0 to (faux) 10bit HD (1080) 4:4:4

[newpball]

Anybody doing this?

What's your approach and what are the gotchas?

[hello_hello]

Oh my...... Someone call the resolution police! Notify the media! It sounds like newpball is downscaling.

[pandy]

Anybody doing this?

What's your approach and what are the gotchas?

Yes (but usually to 8 bit with avisynth)
Resize with spline works for me and i need to try use ffmpeg for this.

[racer-x]

It depends on weather or not you plan on doing color grading...

FFVideoSource("D:\Stock\NX1_4k_24p.MP4")
ConvertToRGB(matrix="Rec709", interlaced=false) #(or Rec601 if that's what your camera uses)
Spline16Resize(1920, 1080) # (or whatever resizer you want)

# (If you plan on color grading, you should use matrix="PC.709") #

[poisondeathray]

It's easy to keep 4:4:4 in YUV, or 8bit RGB, but the "gotcha" is you can't just do a simple resize if you want to keep "10bit-ness" - it will result 8bit quantized values (discrete jumps, banding).

The key is to apply dithering in the bit depth conversion. Easiest way is to use AE in 32bpc mode, which does dithering by default for bit depth conversions. Premiere and Vegas, and most NLE's do not, so you get similar results as avisynth or ffmpeg (banding) . It should be possible with vapoursynth or avisynth with stack16 using dither tools , but it's can be tricky to get it working properly

There might be a switch in ffmpeg to apply dithering, but ffmbc does apply dithering to bit depth conversions by default, so you can do it with ffmbc. The only 10bit 4:4:4 intermediate that is "usable" in most applications is prores444 . You can use r210 or r10k, (which are 10bit RGB uncompressed), but they are not that compatible in all applications. But v210 (uncompressed 10bit 422) is highly compatible in most applications.

[newpball]

So the dithering in AE would come after the Avisynth processing?

I suppose DNxHD would be an alternative to people who are "allergic" to prores444 on the PC?

Looking at the footage coming from the Panasonic G7 it is Full Range Rec.709.

Question also is if 4:4:4 is going to give much above 4:2:2, seems that 4:2:2 would be the more practical road.

[poisondeathray]

So the dithering in AE would come after the Avisynth processing?

You don't need to use avisynth - AE does dithering with bit depth conversions automatically . But if you use avisynth for other stuff, then yes AE has to come after

I suppose DNxHD would be an alternative to people who are "allergic" to prores444 on the PC?

Yes, dnxhd should work, but prores is more compatible , with fewer issues even on a pc . There are more issues with levels interpretation with dnxhd , unless you use Avid MC .

Looking at the footage coming from the Panasonic G7 it is Full Range Rec.709.

Question also is if 4:4:4 is going to give much above 4:2:2, seems that 4:2:2 would be the more practical road.

It depends on the source footage and what you plan to do with it. But the UHD chroma planes are 1920x1080 to begin with . So keeping 1920x1080 4:4:4 means you don't downscale them, you keep the original chroma resolution. But the actual chroma quality or actual effective chroma resolution most likely isn't 1920x1080

[newpball]

So the dithering in AE would come after the Avisynth processing?

You don't need to use avisynth - AE does dithering with bit depth conversions automatically

Oh great, got to try that!

I suppose DNxHD would be an alternative to people who are "allergic" to prores444 on the PC?

Yes, dnxhd should work, but prores is more compatible , with fewer issues even on a pc . There are more issues with levels interpretation with dnxhd , unless you use Avid MC .

It depends on the source footage and what you plan to do with it. But the UHD chroma planes are 1920x1080 to begin with . So keeping 1920x1080 4:4:4 means you don't downscale them, you keep the original chroma resolution

Makes sense.

I just started adding 4K (have only one 4K camera the Panasonic G7) for the time being most of my videos will still be 1080.

[racer-x]

Looking at the footage coming from the Panasonic G7 it is Full Range Rec.709.

So when are you going to post example footage of your new G7?

[newpball]

Looking at the footage coming from the Panasonic G7 it is Full Range Rec.709.

So when are you going to post example footage of your new G7?

Next week, among other things, I will be heading for the Forest Gump point, would be nice to score some G7 footage there.

[hello_hello]

It's easy to keep 4:4:4 in YUV, or 8bit RGB, but the "gotcha" is you can't just do a simple resize if you want to keep "10bit-ness" - it will result 8bit quantized values (discrete jumps, banding).

Couldn't you do it all in 16 bit using the Avisynth Dither Tools script/plugin? (Edit: Sorry, I just realised I should have read your post #5 a bit more carefully)

Assuming you happen to be the type of person who enjoys destroying the picture detail by downscaling, of course. Fortunately though, Dither Tools includes instructions for using an 8 bit sharpener on a 16 bit clip.

It'll convert from YUV to RGB and back and the conversion to YUV supports the following output types:

YV12
YV16
YV24
YV411
Y8

http://avisynth.nl/index.php/Dither_tools

I've barely done any 10 bit encoding but doesn't the 10 bit x264 encoder accept a 16 bit input, or couldn't you re-encode it via something like Avs2YUV or avs4x264mod? Even if you needed to dither it down to 10 bit first, although I'm not sure that'd be necessary.

[newpball]

If you happened to be the type of person who enjoys destroying the picture detail by downscaling, of course.

Getting a large dose of my own medicine here!

[poisondeathray]

@hello_hello - that's the "tricky" part for avisynth - most programs don't understand the stack16 format . Yes, 10bit x264 is about the only way you can get it out, but most NLE type programs don't understand 10bit x264 , so you usually have to convert it to something else after . It's easier do it directly in ffmbc or AE

To verify if something is actually 10bit or has interpolated 10bit values, you just look at a color picker in a 10bit or higher compatible program. If it's 8bit quantized values, you will get jumps like 30,34,38.. for a 0-1023 10bit gradient. Proper conversion will show values like 30,31,32,33...

[newpball]

Looking at the footage coming from the Panasonic G7 it is Full Range Rec.709.

So when are you going to post example footage of your new G7?

Next week, among other things, I will be heading for the Forest Gump point, would be nice to score some G7 footage there.

Not exactly the Forest Gump point but close.

A panning test run of the Panasonic G7 in 2160p24 2.40:1 (UHD)

Using CineD and FilmConvert Kodak Vision3 film (no grain) simulation.

[racer-x]

Looks good.

How do you like the camera so far?

[newpball]

Here is a second one, made a bit earlier in the day:

[newpball]

And here is a hand held dynamic range test:

[Jamaika]

Interesting topic.
Maybe I shouldn't speak because I have no contact with prores4444, but ...
I read a lot of articles for prousers that a film should be in 4K with high depth and then scaled down. Then there are appropriate programs that of 4 pixels throw the most extreme value and thus get rid of the noise.
You're doing the opposite. With low depth going up.
I have Sony Vegas 13. Now we import prores4444. And what's next ???
Codecs YUV AJA or Blackmagic V210, R210, R10K fall off. I was never able to come to an original color {fullrange, colorspace}. There were only RGBA 32bit uncompressed. Unfortunately, the preview have RGBA 32bit and apparently already is the ProRes conversion. And then I can create for ex. Webm VP9 444 10bit BT709. I don't know, support Youtube this? I would not recommend now X265 or colorspace BT2020. Many programs badly displays colors. On the final note, the new bluray 4k will not support a 10bit i444 FullHD.

[newpball]

And some fun with that old gold rush HDR sepia gold.......

[newpball]

OK, last sample, more contrasty curved:

[newpball]

Looks good.

How do you like the camera so far?

For the price it is a steal!

Some small points I would like to make:

• It's easy to handle, very light but it does have a plastic like feel.
  
• It is not weather sealed, so make sure you have a coat!
  
• Mounting some QR plates can block the SD and battery location.
  
• Manual mode works great, has focus peaking, lots of config options.
  
• Histogram is a joke.
  
• Use CineD (except perhaps in high contrast situations, need more testing)
  
• Use full range especially if you are going to use custom profiles.
  
• Daytime video is pretty decent unless the contrast gets too high.
  
• Sunrise/sunset shots are problematic to say the least, filtering the red/orange and adding it back in post may help handle the tonal contrast or perhaps i.Dynamic at low settings, need more experimentation.
  
• Don't even think of shooting in low light.
  
• If you record mostly 24p you would need a couple of ND filters to keep exposure at bay and the lens at the sweet spot.

Yesterday I went out making some sunset pictures of the San Francisco Bay. However I did not like the result, the dynamic range was simply not there. I have not given up but clearly I need more experimentation with custom profiles and filters. It's certainly not a RED or ARRI.

[racer-x]

Thanks for that review. How is the image stabilizer? I assume you went with the 14-42 lens. If I got one, I was thinking getting it with the 14-140 lens for $1,000 through B&H.

[newpball]

Thanks for that review. How is the image stabilizer?

No idea, I mostly shoot tripod and monopod.

I fear some people will start to foam at the mouth again but I think that holding a camera in the hand (no not on the shoulder or with a steadycam) is a recipe for disaster for almost all kind of footage.

I assume you went with the 14-42 lens. If I got one, I was thinking getting it with the 14-140 lens for $1,000 through B&H.

I love B&H but this time you might want to check Adorama because they have a special giving you a free Audio Technica mic.

The 14-140 (and also the 14-42) are obviously entry level lenses they are nothing to write home about so, if you want to have the additional range you might as well get the Olympus M. 40-150mm F4.0-5.6 for $99 I suspect it to be of comparable quality. With the money you save you can get some good ND filters.

Because if you record 24p you are absolutely going to need those.


Now if you really want to get your feet wet in video then for the details get a cine lens, not one with a fancy German name, that is, unless you have cash to burn, but the poor man's version. For instance a Rokinon Cine 50mm or a Rokinon Cine 85mm both at T 1.5 (yes, we are in T-land now). Of course everything is manual but that speaks for itself!

[newpball]

Here is a few second test of a shot of the San Francisco Bay area without an ND filter, to show my point. The lens had to be stopped all the way to F22 to get proper exposure and for MFT lenses that is just too much, it is not sharp enough.



But if you watch carefully you can still see "Jonathan Livingston Seagull" flying in the sky.

[newpball]

Now compare the prior video with a shot of the San Francisco Bay but now taken with a telephoto lens and ND filter: