[HN Gopher] Neural Actor: Neural Free-View Synthesis of Human Ac...
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       Neural Actor: Neural Free-View Synthesis of Human Actors with Pose
       Control
        
       Author : Hard_Space
       Score  : 134 points
       Date   : 2021-06-04 12:48 UTC (10 hours ago)
        
 (HTM) web link (gvv.mpi-inf.mpg.de)
 (TXT) w3m dump (gvv.mpi-inf.mpg.de)
        
       | Reason077 wrote:
       | "Stantard deviation"? Typo?
        
       | TimPC wrote:
       | I'm very glad they used a hyphen in the title as it completely
       | changes the expected meaning.
        
       | drcode wrote:
       | I assume we'll see some optimized version of this for NPCs in
       | video games soon.
        
       | spywaregorilla wrote:
       | Interesting. My first observation is that the rendered people all
       | have really tight clothing on. The model guesses at some creases,
       | but it probably wouldn't guesstimate cloth physics very well.
       | 
       | I would tend to think you would have much better results
       | synthesizing a mesh with a NN and getting a game engine or
       | something to do this part with the animation.
        
         | ridaj wrote:
         | That's especially visible when comparing with the "driving
         | person", who is floating in a loose open trench-coat that flits
         | about as they dance
        
       | kossTKR wrote:
       | Love the dancing ha! Also is this ready to be used on a small
       | project, knowing very little og NN's?
       | 
       | I just need s bit of motion tracking to be used on various
       | figures on a webgl website, have been looking at the iphone depth
       | sensor, the kinect and Mixamo.
        
       | m3kw9 wrote:
       | How is this different from putting a skin on the real actor?
        
       | montroser wrote:
       | This is incredible. Interesting how combining the neural net with
       | 3d mesh and texture map provides the best results of all the
       | approaches they tried.
       | 
       | I am both excited and terrified for what this stuff may yield in
       | our future realities.
        
       | iandanforth wrote:
       | This page causes multiple mp4 download prompts to open in Firefox
       | (v89.0, OSX) for me. Anyone else seeing this?
        
         | philote wrote:
         | Not for me (v88.0.1, OSX)
        
         | Hard_Space wrote:
         | No, not for me. I think you'll need to review file association
         | actions in Firefox prefs. I have to do this regularly for PDF.
        
         | jkingsman wrote:
         | I'm on Chrome 90.0.4430.212 on Catalina and I had multiple
         | videos with narration all start on page-open. Had to mute the
         | page because I couldn't figure out which one was talking.
        
       | Abishek_Muthian wrote:
       | Soon those who have motor control issues or other problems would
       | be able to just feed the script and get their virtual self on
       | video with all the movements which isn't possible in reality.
       | 
       | Which might be necessary, Considering even a LinkedIn profile
       | requires some TikToking now in the name of 'Introduce yourself in
       | a 30 second video'.
        
       | grawprog wrote:
       | The results remind me of high quality rotoscoped characters. Like
       | if the original Mortal Kombat got an HD remaster or something.
       | They look good but not real.
       | 
       | If they do start replacing actors with these, everything's gonna
       | look like a Ralph Bakshi movie.
        
       | TchoBeer wrote:
       | My first thought is that this will make for some pretty good
       | memes
        
       | fareesh wrote:
       | TikTok filter - now you don't need to dance, just use the filter
        
       | indiantinker wrote:
       | Anybody can dance now! yay!
        
       | hliyan wrote:
       | Another 10 years of progress, better facial expression control
       | and voice synthesis, I suspect highly paid actors will be a thing
       | of the past.
        
         | qayxc wrote:
         | This has been prophesised before (last in the early 2000s) and
         | didn't come to pass.
         | 
         | I wouldn't expect that to change given this technology either.
         | There's a market that would benefit greatly from this, though:
         | marketing and training videos as well as stock-footage.
         | 
         | Some companies (Samsung comes to mind) already use synthetic
         | avatars to represent their products. Artificial influencers and
         | the like will also take the place of real humans.
         | 
         | Film actors, though, not so much. There's more to a successful
         | actor than just appearing in film (who'd sit at meet & greets,
         | autograph signings or attend shows?) so there's little reason
         | to replace _living_ actors. Deceased ones, though...
        
           | makapuf wrote:
           | The tendency is even reverse with highly paid actors being
           | hired for only the voice acting featuring in computer-
           | animated movies (where great voice-only performers would be
           | cheaper)
        
             | refactor_master wrote:
             | Humans basically want to belong to a tribe, which is why
             | there's always a certain equilibrium with relatively few
             | "famous" people on one side. If AI and the Internet made
             | everyone exceptional, nobody would be exceptional, and we'd
             | just find random idols to gather around anyway (sort of
             | what we already do).
             | 
             | Sure, you _could_ use AI to act, _or_ you could follow your
             | most basic gut instinct and slap a famous-for-being-famous
             | person on it and call it a day. Because it's going to work.
        
               | CyberDildonics wrote:
               | This is nonsense.
               | 
               | First, actors are not famous for being famous, they are
               | famous because people recognize them and eventually learn
               | their names.
               | 
               | Second, the name recognition is why they get cast as
               | voices. Their name can then be used to promote the movie
               | and the actors themselves can go out and promote the
               | movie.
        
               | refactor_master wrote:
               | At first you get famous for being above average. Then you
               | become more famous for being famous. Why are they paid in
               | the several millions when most jobs are not? Are they
               | _that_ much better at their job, than you are at yours?
               | Probably not. But now the ball is rolling.
        
               | CyberDildonics wrote:
               | I'm sure that is what it might look like with a vague
               | awareness of entertainment, but it is not only not
               | reality it doesn't even make sense. It also has nothing
               | to do with the thread.
        
         | listic wrote:
         | I dunno, when I first saw a Vocaloid on stage, my jaw dropped
         | as I realized that in 10 years highly paid pop stars will be a
         | thing of the past. Yet, it doesn't seem like music industry is
         | switching to synthetic avatars.
        
         | acjohnson55 wrote:
         | When people talk about replacing artists with virtual artists,
         | I think an important missing piece is that people are into
         | performance _because_ a human with a story is doing the
         | performing, not just the aesthetics of the end result. For the
         | most part, great art isn 't hermetic. It's situated within the
         | context of the artist's personal story and career arc, an the
         | relationship of those to the audience / fanbase.
         | 
         | We probably will see greater uptake of virtual art and artists,
         | but it hasn't been and won't be a revolution that sweeps away
         | human performance.
        
         | jfengel wrote:
         | If anything, it's the low-paid actors that would go instead.
         | 
         | Highly-paid actors are celebrities. They are engaging in a way
         | that is incredibly hard to describe but nonetheless seems to be
         | widely recognized. They aren't necessarily "good actors" (a
         | term that is itself hard to define), but people enjoy looking
         | at them. People go to a film just because some well-known actor
         | is in it, and that's what makes them so valuable.
         | 
         | Every film set is chock full of talented people. Plenty of
         | people could have done great work as, say, Tony Stark.
         | Hollywood is full of beautiful and talented women who just
         | never manage to get that "it factor". To displace highly-paid
         | actors they'll have to replicate that, and that'll open up a
         | whole new set of questions.
         | 
         | The ones who go first will be the low-paid actors who surround
         | them. They are the ones doing sitcom pilots that get shelved,
         | or commercials for dog food and allergy medicine, or being
         | saved from having a bus dropped on them. Such actors are
         | actually reasonably well paid on the days the work (over $1,000
         | a day for big-budget films or TV; $9,064 for a week as a guest
         | star), though most of them work only a tiny fraction of the
         | time. There are more people making a living at that than being
         | a star, though the odds still suck.
        
           | asiachick wrote:
           | You're probably right but we already have the example of
           | Hatsune Miku. Sure she's an exception but the software isn't
           | there yet. At someone point someone will make a truly hit
           | movie or TV show with 1 or more main synthetic characters.
           | 
           | I'm sure when Tron came out lots people said "practical
           | effects will never disappear". And yet with few exceptions
           | they mostly have.
        
             | jfengel wrote:
             | We will definitely have digitally-created stars as a
             | separate medium. We have for a long time had animated
             | characters who don't speak. They still involve intensive
             | human direction to create them, but they don't have human
             | form or human voice. They're still plenty entertaining.
             | 
             | They get to do things that humans can't do. They can
             | entertain in entirely novel ways. Using them as a
             | substitute for human actors is kinda the faster-horses-not-
             | cars of movies.
             | 
             | We use CGI characters for inhuman effects, but I think it's
             | often not very effective. I don't care for most superhero
             | movies because I don't really care about watching CGIs
             | punch CGIs harder than human actors could do. There aren't
             | any stakes; there's no dramatic risk. I'd rather watch a
             | martial arts movie, which is limited by what humans are
             | capable of.
             | 
             | That's still something we're learning. Part of what made
             | the Lord of the Rings films more interesting than the
             | Hobbit follow-ons was that the latter used more practical
             | effects. New Zealand was a big star in LotR; Hobbit used
             | more CGI backgrounds. Audiences felt the sense of place.
             | 
             | We'll improve the tech so that it seems even more
             | realistic. The new technology used in The Mandalorian is
             | really exciting (though I'd be curious to see how it played
             | on a big screen). But it was at its best when it made up
             | very real-world seeming worlds, while animation uses
             | digital worlds in totally unrealistic and even more
             | exciting ways.
             | 
             | So I'm expecting that we'll continue to have practical
             | effects in the best movies starring humans, and continue to
             | have human stars. But we're still waiting for the first
             | mega-hit CGI star who can do whatever magic it is Robert
             | Downey Jr. does. When they can catch that, RDJ may well be
             | out of a job -- not replaced, but the entire enterprise
             | gone.
        
         | knicholes wrote:
         | My mind went towards stuntmen. Now, studios can record natural
         | actions for a large database of actions, and pick and choose.
         | Instead of the Wilhelm Scream, you could see "Flip #564" and
         | "Crash #827". If it doesn't even matter what shape the stuntman
         | is, it seems to me like the industry might be looking to fill
         | that occupation less and less.
        
           | CyberDildonics wrote:
           | There have already been CG stunts for multiple decades. You
           | still have to match the lighting of the photography to
           | integrate the CG even if you have something like this
           | captured with flat texture maps.
           | 
           | The fidelity is also a big issue, flat textures and rough
           | normals are not going to hold up to much scrutiny.
        
         | eMGm4D0zgUAVXc7 wrote:
         | The move to virtual characters is already happening on Twitch /
         | YouTube, check out CodeMiko:
         | 
         | https://www.youtube.com/watch?v=CsQjxEd-gsw
        
           | aigen001 wrote:
           | It's also makes business sense to use virtual characters.
           | 
           | If you are a streamer whose sole income is based on sites
           | like twitch/youtube, getting banned could mean the end of
           | your career and social life. Many streamers live together and
           | collaborate with one another and sites like twitch have rules
           | where you can't stream with banned streamers. So getting
           | banned doesn't just mean getting banned from the site, it
           | also means getting banned from your friend group because
           | interactions with you could get them banned too.
           | 
           | With virtual avatars you could evade a ban by changing your
           | model and also use a voice changer. I haven't personally
           | heard of any cases where streamers use virtual characters to
           | evade bans but I'm sure its at least happened.
           | 
           | It also becomes easier to become a marketing tool. Since Code
           | Miko isn't a physical entity, she could easily be used in
           | video ads just by sending ad agencies her model. No more
           | flights to video shoots, all you need is a 3d animator.
        
         | TimPC wrote:
         | I think this technology is in its infancy and we might be
         | looking at far more than 10 years to even get the functionality
         | to make this possible regardless of whether it could actually
         | replace highly paid actors. Occlusion and multi-agent are
         | typically hard problems in image spaces, so once you add
         | objects and other agents to a scene it becomes a great deal
         | more challenging to make the motions life-like and realistic.
         | Admittedly if you're mapping onto an actor in the scene with
         | other objects and just changing their appearance it might be
         | doable but you might run into substantial challenges if your
         | target is 5ft8 and your source is 6ft2 (or Vice Versa). If
         | you're not using a source-target mapping at all you have the
         | challenge of generating realistic movements given all the
         | obstacles and interactions, which is much harder than the
         | current one-agent zero-object space.
        
       | whitten wrote:
       | So this method seems to create an inner core "skeleton" that is
       | then used with various shells.
       | 
       | How is this method compared to a commercial product such as Poser
       | ?
        
         | qayxc wrote:
         | Does Poser work with photos and videos as inputs?
         | 
         | If not, there's your answer.
        
           | bsenftner wrote:
           | No.
        
         | gedy wrote:
         | You don't need to create or capture a mesh. This is
         | synthesizing one from a few 2d images, with impressively
         | accurate results.
        
         | wokwokwok wrote:
         | Poser requires an existing rigged, textured mesh.
         | 
         | Poser requires that you manually animate the skeleton.
         | 
         | This approach is more like a mixture of mocap/photometry; given
         | an input video (a) and (b), synthesise a fully textured model
         | from (a) and apply the motion from (b) on it.
         | 
         | Of course, the output of this is horribly bad compared to state
         | of the art 3d models; the point is that the inputs are trivial
         | and it shows that NeRF are increasingly plausible as a solution
         | for real use cases.
         | 
         | Of course... this is all a bit 'proof of concept stuff'.
         | 
         | > To further evaluate our method on a wider variety of body
         | poses and more challenging textured clothing, we captured a new
         | multi-view human performance corpus with 79 - 86 cameras at a
         | resolution of 1285 x 940. It contains four sequences, N1-N4,
         | and each has 12,000-16,000 frames for training and around 8,
         | 000 frames for testing
         | 
         | These captured images are also, notably, green screen, although
         | not with the traditional mocap markers.
         | 
         | So, no, you're not going to get a 3d animation from a video off
         | your phone anytime even remotely soon.
         | 
         | ...but, it's still pretty darn awesome, and they're going to
         | release the datasets for others to play with.
        
       | l1n wrote:
       | I really really wish that there was a norm of uploading code at
       | the same time as the paper. The number of "code coming soon!"
       | buttons on these sorts of sites (oftentimes several years in the
       | past) is far too high. If you can't play around with the model,
       | how can you tell the level of cherry-picking that the method has?
        
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       (page generated 2021-06-04 23:01 UTC)