Monday, 12 February 2018

1080P Blu-Ray vs. 4K UHD Blu-Ray: "Pacific Rim" - Digital "2K" Filmmaking (and a look at Blue Planet II)


Having looked at Dunkirk (70mm IMAX - 65/15-perf and 65/5-perf) and Interstellar (hybrid of 35mm and 65-15-perf) previously, over the next few weeks, when possible I'm going to try for a survey of comparisons using different types of movies and show the kind of resolution difference one might see going to 4K.

Today, let's consider a very common type of movie production - digitally filmed movies mastered to a 2K Digital Intermediate (DI). In Real or Fake 4K, these would of course be classified as "Fake 4K" movies that would need to be upsampled going from 2K/1080P to the 4K/2160P on your shiny new UHD Blu-Ray disc and 4K screen.

Pacific Rim would be a good example of this type of production in a big budget movie (said to be ~US$190M back in 2013). It was captured on Red Epic cameras capable of up to 5K (5120x2560) raw frame quality, then downsampled to a 2K Digital Intermediate mixed with 2K rendered visual effects.

While admittedly not a great movie, for guys and gals who like steam punk themes, monsters, and of course really big robot mechs, Guillermo del Toro serves up quite a feast of a real-live action anime. Nothing wrong with turning your brain off and enjoying some mech-on-monster brawl once awhile :-).

For the record, the UHD Blu-Ray video averaged ~61Mbps 10-bit HEVC and the Blu-Ray averaged ~24Mbps 8-bit AVC. These are good numbers and suggest high image quality without significant artifacts from starvation from inadequate bitrate (remember, video is always "lossy").

As usual, I'll use the typical settings for madVR for HDR-to-SDR conversion as well as high quality NGU upscaling settings:

Target 200 nits resulted in reasonable output brightness for comparison.

NGU Sharp - very high quality for chroma upscaling.

NGU Sharp, very high for luma doubling.
Let's have a look at scenes from across the span of the movie...

1. Kaiju Blue (00:02:20.500)




Right off the bat, we notice a difference in the contrast (gamma) between the two scenes. The HDR version looks "punchier" with brighter whites and darker blacks. Also color-wise, it looks a bit more saturated. Depending on the setting of the HDR conversion, we can adjust the brightness, but that contrast difference is evident.

However, resolution-wise, notice the lack of a significant difference when compared 1:1 on a high resolution monitor.

2. Holding Hands (00:02:25.000)



Again, we see the fact that this is a 2K DI. Notice the same resolution for the outlines of the (almost) silhouettes and the flames of the ship on fire and billows of smoke in the distance appear to be of the same resolution. Colors looking more saturated, in this case "warmer" in the UHD Blu Ray version.

3. Marshall Pentecost (00:11:53.000)



Here's Idris Elba's character. Same fine detail as seen in the "Marshall Pentecost" pin and military bars for example.

4. Mako (00:39:32.000)



As in previous comparisons. It's good to look at fine details like strands of hair, etc. Again, we see a stronger contrast level with the HDR version but otherwise, details like eye-lashes and hair strands do not obviously stand out with the 4K version as any more defined.

5. Ruined City (00:52:14.000)



Lots of potential detail here in this scene. But I think it's very clear also that the "4K" version is suboptimal and there is surely much more resolution we can extract if this were a true 4K image.

6. Weapon Power-Up (00:53:59.000)



Littered throughout the movie are scenes of the characters interacting with bright neon-glowing hologram-like user interfaces... Like this one inside the giant mechs ("Jaegers").

A few weeks back SUBIT wondered about separating the image into luma and chroma components to have a look. Here ya go:

Luma
Chroma
Okay, so this is not the best example, because we know this movie is based on a 2K DI... Notice that both the luma and chroma samples appear to be of the same resolution. We'll look at this again in the future when there could be more interesting differences to point out in other types of productions.

7. Hero Emerges (01:02:28.000)



This movie is obviously very CGI driven - I'm sure tons of green-screen type work for the actors. This scene is clearly a render showing the same resolution between 1080P and UHD/4K/2160P versions.

8. Evac Pod (01:59:30.120)



Last shot for you all... Very obvious color and contrast differences. Much starker contrast between the darkness of the sea and the light-colored evac pod through the madVR conversion. I see a little more artifact in the 1080P image, possibly due to bitrate differences or maybe the upsampling algorithm. But overall, the absolute resolution again looks the same; there's really not much more you can see "into" the 4K scene.

Conclusion...
Okay, relatively "short and sweet" post this week; I mainly just wanted to show the comparison images for those who want to reference a practical example. Pacific Rim is I think a good prototypical example of a commonly-found digitally-captured "fake 4K" movie you can buy on UHD Blu-Ray these days (other recent movies include American Made, Wonder Woman, It, Kingsman: The Golden Circle, the upcoming Thor Ragnarok, Justice League, Wonder, and The Shape of Water). In terms of spatial resolution, clearly the limitation of the 2K digital intermediate is evident. But despite this limitation, the image still looks very good because the movie utilized HDR well for eye-popping contrast, brightness, deep blacks and of course a wider potential color gamut with stronger saturation. If you want to show friends the difference HDR makes, this is a "pure" example of the very obvious difference without any pretense of a resolution upgrade. So how much money would you spend on a movie for this kind of dynamic range "improvement"? (Is it even an improvement in your eyes?)

Obviously if you have a very large screen at home, the lack of higher resolution can be seen. But in a fast-paced movie like this with all kinds of motion and cutting in and out every few seconds much of the time, there's little time to stare at a scene anyway :-).

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To close this post, I just want to put out a strong recommendation if you have 4K/HDR playback to consider grabbing BBC's Blue Planet II! Like Planet Earth II from last year, the quality of this UHD Blu-Ray set is simply amazing with "never seen before" mindblowing undersea footage. Another documentary piece to show off the image quality from your ultra-high-resolution screen.





Now some 1:1's:



While there is some variability in the resolution and color quality depending on the equipment used (for example, some of the deep sea scenes were obviously shot on lower resolution equipment), it's obvious that much of this was shot in 4+K and the digital intermediate was in 4K. 

That my friends is what I call real 4K! Simply beautiful.

Hope you're all enjoying the sights and sounds...

8 comments:

  1. Your geek was given full rein here. I watched this movie on 720 p file, sorry I am not sure if that is the right technical term. Regardless, the visual impact of the movie was immense, even at that lower resolution!

    ReplyDelete
    Replies
    1. Hey Martin,

      720P (1280x720) is still nothing to sneeze at! For many films and depending on the size of your screen, that still looks very much better than "standard definition" 480P from the DVD days...

      Delete
  2. That confirms my thoughts I have since months now.

    1 - madVR is amazing (Upscaling with NGU is incredible !!!)
    2 - madVR is amazing bis (HDR to SDR tonemapping algo are so close to restore a 1:1 SDR source pic)
    3 - 4K UHD BD are super disappointing (staying polite). Thanks to the low BD50/BD66 storage capacity and the bitstarved content.
    4 - 4K UHD BD are super disappointing bis. Thanks to the different commercial H.265 encoders and x265 far from being mature. Way too much details and grain lost.

    I wont upgrade my sub 4K collection before a while...

    Cheers.

    ReplyDelete
    Replies
    1. Hi Hash,
      Just like "hi-res" audio, it's important to focus on the "provenance" of these 4K UHD Blu-Rays. This is why I want to do a series of posts like this showing the difference 70mm, 35mm, 2K DI, etc. makes so consumers (myself included!) are aware of the potential benefits.

      In the situation here, with a 2K DI, there's clearly nothing to be gained compared to an excellent upscaler like madVR NGU. Obviously, other lower quality upscaling will not be as good. It's therefore important to be mindful of the movie one might be interested in buying in 4K and determine if we want to own it for the HDR re-grading rather than any spatial resolution benefits...

      Good quality UHD Blu-Rays these days are BD66 and look very good. Much better bitrate than typical 4K streams! Of course, much of the total bitrate can be taken up by the many audio tracks available on these disks.

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  3. Thanks for doing the luma/chroma comparison!
    I can confirm that both the samples have the same resolution in color.
    Here I bumped the saturation/contrast a bit to make it more visible:
    https://i.imgur.com/eVtTpcq.png

    ReplyDelete
    Replies
    1. Nice SUBIT.

      Yes, I actually increased the contrast just a little bit in the picture I posted above not to the extent of your processing... I've already seen movies where indeed the chroma is of higher resolution. Will show that in the days ahead :-).

      Delete
  4. Nice work, Archimago. How are you saving screenshots? MadVR has separate settings for screenshots, and they could be very different from the settings for video viewing.

    ReplyDelete
    Replies
    1. Hi Yuri,
      Nothing fancy with the screen capture. Just played the file with MPC-HC 64-bit using madVR. Once I decide on which frame to capture, I pause, go to the specific frame. Using Jing to capture the screen shot as displayed on my monitor and save losslessly as PNG.

      Maybe using madVR's "screenshots" setting and saving a PNG in MPC might look different. Haven't tried :-).

      Delete