When the movie "Legend" was released, when Jackie Chan saw his younger AI clone, he sighed and recited a poem: "Black hair turns white in a moment, to whom can I tell how old I am. If the spring breeze has pity on flowers, could you please let me be young again?" This video was widely circulated on short video websites.

Jackie Chan said: "I can't go back to my youth, but movies can take me back." The 27-year-old AI Jackie Chan, who is able to fight on the battlefield and fall in love with the fairy princess Nazha, has undoubtedly become the biggest highlight of the movie "Legend".

Stills from Legend

Director Stanley Tong and Jackie Chan have collaborated for more than 30 years, jointly creating their signature kung fu comedies, including "Police Story 3", "Rumble in the Bronx", "The Myth", "Chinese Zodiac", and "Kung Fu Yoga", which have witnessed their friendship and tacit understanding along the way.

In 2005, Stanley Tong and Jackie Chan's "transitional work" The Myth was released. It broke away from the previous Hong Kong martial arts routines and was set in the Qin Dynasty. It told a story of unforgettable and extraordinary love, with a plot that reflected the past and the present. It can be called the "pioneer of time-travel" in the early 21st century movies. When it was released, it set a global box office record of 120 million US dollars and was regarded as a classic Sino-Korean co-production.

Later, "The Myth" was made into a TV series, starring Hu Ge and Bai Bing. In the years when the IP was the hottest, Tang Jili publicly stated that he would not make a sequel to "The Myth". Many years later, Tang Jili "broke his promise". The reason for his change of mind was that on the one hand, he was inspired by the majestic and vast land of the Western Regions and had new story inspiration; on the other hand, the development of new technologies gave him the opportunity to "cooperate" with the younger Jackie Chan.

The Legend, which is old wine in a new bottle, has grossed over 50 million in three days, which is not a good result for Jackie Chan's movies. Douban scored 5.5, which is the same as many of Jackie Chan's movies in recent years, which always makes people feel helpless that "Lian Po is too old".

"Legend" box office breaks 50 million poster

Bona President Yu Dong once said in the Shanghai Film Festival preview of "AI Jackie Chan" that "the emergence of AI technology will make movies no longer an art of regret". But obviously, at this stage, the effect of AI blessing movies in this way is not satisfactory. During the release of the movie, when Tang Jili was interviewed by a reporter from The Paper, he did not shy away from the fact that the film had many frustrations in terms of completion. However, as a trial work of AI technology deeply involved in the production of Chinese-language films, "Legend" still has its positive significance that cannot be ignored.

The following is director Stanley Tong’s sharing of his experience working with “AI Jackie Chan”.

Director Stanley Tong

【dialogue】

AI creates "introverted" Jackie Chan, a big step forward for film technology

The Paper : In a previous interview, you said that you once refused to shoot a sequel to "The Myth". When did you start to think that "The Myth" could have a "sister film"?

Tang Jili : I once said that I would not make a sequel to "The Myth" because the story of Princess Yu Shu and General Meng Yi is complete enough and it is difficult to extend a sequel from it.

The turning point happened three years ago when I saw a documentary about the Hexi Corridor. It recorded that during the reign of Emperor Wu of the Han Dynasty, Huo Qubing established China's first military horse farm and led 800 cavalrymen deep into the heart of the Xiongnu. He was later named the Champion Marquis. After watching the documentary, I went to the northwest again and visited the Hexi Corridor in Gansu and Xinjiang. I was deeply moved. Canyons, deserts, and barren lands, that sense of vicissitudes made me reverent. We are now driving in the northwest with air conditioning on and feel exhausted. In order to protect our territory from foreign invasion, the martyrs and cavalrymen traveled thousands of miles. What kind of scene was that? This experience made me determined to make a movie about Huo Qubing.

I originally wanted to write about Huo Qubing, but the "important historical figure" would have more restrictions, so I chose fictional characters around him, which can better express the romance of love in troubled times. When I was a child, I watched "Doctor Zhivago" and liked the feeling of people and lovers being separated under the background of war. So I chose to shoot "Legend".

Jackie Chan in The Myth (2005)

AI Jackie Chan in Legend

The Paper : At what stage did you decide to use AI in the creation of this film? What challenges did the use of AI technology bring to this film?

Tong Jili : Jackie Chan and I both love history and often talk about our favorite heroes, including Yue Fei, the Overlord of Western Chu, and Huo Qubing. These heroes were very young at the time, but when I met Jackie Chan, he was already 37 years old. At that time, we worked together to shoot "Police Story 3: Super Cop". I have watched Jackie Chan's movies since I was a child. I especially like "Drunken Master" and "Young Master Long" when he was young. He was handsome and cute at that time. It can be said that as a director, I missed Jackie Chan when he was young. This miss has become a regret. I really hope to see Jackie Chan play Huo Qubing from the age of 17 to 24.

Jackie Chan during Project A (1983)

Jackie Chan in Police Story 3: Super Cop (1992)

More than two years ago, I learned about AI technology, including DeepFace. I saw a friend demonstrate it and thought it was quite interesting. That’s when I came up with the idea of using AI technology to enhance filmmaking.

When I first learned about the technology, it had low pixels and could only be displayed clearly on a small screen like a mobile phone. In addition, face-changing technology is limited in many aspects. For example, if the angle of the face exceeds 45 degrees, the face-changing technology cannot keep up.

Moreover, although Chinese films have made some use of this technique in the past two years, no film has truly established a new character. For example, Wu Jing and Andy Lau have shown their youthful looks in the film, but the roles they played when they were really young were relatively simple. This kind of youthful operation is actually artificially "making people young" instead of creating a young and vital character.

But this time, we want to create a new, real "character". In the movie "Legend", an archaeologist unearthed a Hun jade pendant from a batch of Han Dynasty war horses. Once the jade pendant was unearthed, the master and the apprentice both dreamed of the same young man. The Jackie Chan that appeared in the vision was actually the Jackie Chan they dreamed of, not the Jackie Chan we have seen in reality. Since it was the Jackie Chan in the dream, we used AI to make many different versions, and in the end we all liked the current version better.

Jackie Chan in "Legend" and AI Jackie Chan

The Paper : What is the creative process like?

Tong Jili : We input a lot of video footage of Jackie Chan when he was young. AI technology generates images of Jackie Chan's young face and converts these static images into dynamic videos. We made AI Jackie Chan of different ages, and the feelings presented are completely different. The background of our play is to resist the Huns, which is relatively serious, with wars, sorrows, and a heart-wrenching feeling. So in different versions, I chose to express it in a more restrained way, not as a more popular and lively version.

The Paper : Yes, Big Brother’s previous roles were all relatively lively, and it seems that he has never played such a “restrained” role.

Stanley Tong : This kind of Jackie Chan has a sense of freshness. You will find that he is elegant, polite, and very noble. This sense of freshness is also the viewing experience that I hope to bring to everyone through AI technology.

The Paper : Is this choice related to some limitations of AI itself? Will the script be adjusted according to the actual situation of AI?

Tong Jili : When we started filming, AI technology was not yet mature, so there were many situations during the filming process, such as turning the head more than 90 degrees, or blocking the face, and being unable to track. These were all difficulties. Including some literary scenes, the actors' subtle expressions are required, but the digital human's eyes and pupils cannot be completed, including some facial expressions and movements, so we have to use the expression capture and motion capture method similar to "Avatar", and then apply it to the digital human.

During the production process, we shot every shot and every expression many times. Some of them were not only to capture the different feelings brought by the subtle differences between expressions, but also because the skin needs to be changed in the process of face-changing, and a lot of details need to be done, such as tears on the face, knife wounds, and special effects of raindrops falling on the face. Face-changing is really a very complicated process.

Tang Jili on the set

The Paper : This film has a lot of dynamic fighting scenes, and it's easy for the face to turn around or be blocked by other moving objects. How did you solve those dynamic parts later?

Tang Jili : Yes. There are a lot of horse riding scenes in the movie, and the faces and bodies of people move up and down, which is really difficult. If it is completely AI digital people, it will become animation, and we are still a domestic film with a limited budget. For example, Hollywood's "Indiana Jones" did a good job, but their special effects cost more than the cost of our entire movie.

This is just like the news about Huawei that I often see. We don’t have our own chips, but we can’t give up on developing them. There must be many unsatisfactory aspects in the process of development. China has been reforming and opening up for so many years, and we have been crossing the river by feeling the stones. If you want to be the first to try something new, you must first be brave, and secondly, you must take a lot of risks.

In this movie, due to the plot, the difficulty was beyond what I had originally imagined. Many new challenges were added during the filming process. Our technical team had to overcome them. We were making progress during the filming process. From the beginning of post-production to the end, we had many expressions and many shots, and we changed them many times. If it didn't work once, we would do it again.

The Paper : As a director, how do you evaluate the performance of “AI Jackie Chan” as an actor this time?

Tong Jili : To be honest, I am not very satisfied with the film after it was made, but I am also very proud of it. I am proud that I was able to overcome many difficulties and make a young, 27-year-old Jackie Chan. There are some scenes that are actually done well enough, but after the promotion of AI technology, everyone's focus has shifted from watching movies to watching technology, and they think the final presentation of technology is not good. But overall, we can vividly make a general like Jackie Chan when he was young, a character. For us, film technology has taken a big step forward, but we must admit that this big step is still flawed.

I remember when I was shooting "The Myth" in 2004, I was also limited by the technology and budget at the time. The Heavenly Palace in the movie was presented through domestic technology and computer special effects. For me, as a screenwriter and director, I think Chinese films need original works, so "The Myth" is the first time-travel movie, and I took risks to do it. When the results came out, I was actually not satisfied with it. But some audiences were willing to forgive my shortcomings, letting me know that the Heavenly Palace was not perfect, but the floating feeling was innovative and creative, so the audience was willing to tolerate it.

Stills from Legend

The Paper : "The Myth" was a blockbuster back then, and this time "Legend" also has some grand parts, using real tens of thousands of horses to shoot the "army of thousands". Why did you make this choice today when special effects are so advanced?

Tong Jili : This part is very difficult to shoot, especially the horse part, including the frozen scene. All aspects are very difficult. But I think when making a big movie, we want the audience to go to the cinema to watch it. In recent years, many small-scale movies have also sold very well. No one wants to shoot big scenes, hoping to make a lot of money with a small budget.

As a filmmaker, I think I have to choose the scene of "thousands of troops and horses" because I have been reading history since I was a child. In the history textbooks, we can't really imagine the scene of "thousands of troops and horses". Hong Kong films don't have this condition, Hong Kong is too small. But this time I happened to go to Xinjiang, where there is a military horse farm, and Zhaosu County has a Tianma Festival. At that time, they will integrate more than 10,000 horses. We just need to communicate well and let those herdsmen stay for two more days for us to shoot. We will bear the cost of the extra two days, and we can complete the scene of thousands of troops and horses on the screen. I think it is worth it.

I hope that the audience can truly feel the battle situation that our pioneer cavalrymen went through thousands of miles deep into the battlefield. The difficulties they experienced would be difficult to impress the audience if they were not filmed realistically and simulated with computer special effects.

Jackie Chan is still fighting at the age of 70. Humans cannot be replaced by AI.

The Paper : You are an action director by profession. Do you think the use of digital doubles this time can help solve the problem of high-risk operations in martial arts?

Tong Jili : Actually, we haven’t solved too many problems yet. We can splice some actions together, such as somersaults and falling from a horse. Our people and horses are used separately: the horse falls first, and then the people fall in coordination with the horse’s movements. The people also fall for real, but they are no longer falling from a horse. For the overall action, it would be safer if we used pure digital people, but the production of fighting scenes is quite time-consuming and difficult to make good-looking. We can only use motion capture and then add animation. So all our fighting scenes are real shots.

The Paper : In the second half of "Legend", Big Brother himself also contributed his signature, slightly funny fighting scenes. Having worked with him for so many years, when designing action scenes for the 70-year-old Big Brother at this age, will the focus be different from when he was young?

Tong Jili : Actually, there is no difference. I have been working with Big Brother for 33 years now. Since 1991's "Police Story 3", I have been his director and martial arts instructor. So when we are practicing moves, the people from the Cheng family will tell Big Brother some moves that he can still do now, and he will do it himself without a stunt double.

Jackie Chan's characteristic is that he does all his moves by himself, so when we set up the moves, we try to set the moves that Jackie Chan can do. So this time you see, Big Brother is already 70 years old, and in the last frozen fight, he did everything by himself, including falling, rolling, and kicking. This is Jackie Chan's professionalism as an actor, and I admire him very much.

So, we created a young Jackie Chan, but there was no animation CG or body double for the fighting scenes. As a director, I wanted to show the audience that Jackie Chan can still fight, and that he fights so well and has such great skills. Moreover, when filming the scenes of young Jackie Chan, Jackie Chan was actually on the set every day.

Stills from Legend

The Paper : From my personal perspective, when the fight scene behind Big Brother came out, I felt even more that AI cannot replace real people.

Tang Jili : Yes, it is absolutely irreplaceable. As AI technology develops, it will get better and better, and the images will become clearer and clearer, that’s for sure, but the communication between its characters and the audience and the love it arouses from the audience will still be different from that of real people.

So for me, this "Legend" is about innovation, including the script. For example, Zhang Yixing has never played a role with so many laughs before. When writing the script, I hope to give the actors more diverse feelings to show the audience.

Stills from Legend

The Paper : In the past two years, everyone has been discussing AI, including how AI can help the film and television industry reduce costs and increase efficiency. After practicing this time, what changes do you think the addition of new technologies will bring to a film of the size of "Legend"? Did the film also use a lot of virtual shooting technology this time?

Tang Jili : Yes, some scenes are very far away, such as the distant view of the Gansu desert, with more than a thousand cavalrymen, which I couldn’t bring over. For these scenes, I would first shoot empty shots and then come back to synthesize them. I think AI’s cost reduction and efficiency increase are mainly in the art design aspect, which really helped a lot.

Our original art team spent a lot of time to make the art scenes look very realistic and beautiful. Now AI technology can provide us with many options. As a director, I used to need to go online and to the library to look up a lot of information when designing a scene, storyboarding, or even writing a script. Now with AI technology, it can quickly provide reference materials.

In fact, AI technology is still immature. The images produced by Sora are very realistic, but this is only directed by Sora. It cannot represent Ang Lee, Zhang Yimou, Wong Kar-wai, Jackie Chan or me, and it cannot represent the feelings of different directors.

So it can provide us with a lot of reference materials in the process of previewing, storyboarding, art design, and script creation, and can be a very powerful assistant for us, but I think there is still a long way to go before it can become a real "director". Of course, with the development of technology, such assistants will become smarter and master more and more skills.

The Paper : After this collaboration with AI Jackie Chan, would you like to collaborate with it again?

Tong Jili : The copyright is still with Jackie Chan and Bona. If we can overcome the shortcomings and limitations of this stage in the future, there may be opportunities in the future. At present, it seems that it will take some time for AI to improve the pixels, skin texture, and acting details on the big screen. But I am still very optimistic about the potential of digital humans in this regard. For example, if a person plays his whole life from his twenties to his seventies, then if he can only be replaced by other actors when he was twenty years old, the audience will still be more likely to be distracted. However, if AI technology matures, some similar long-span story content in the future can be completed by the same actor.

The Paper : I saw that you had previously imagined that you could work with Anita Mui and Leslie Cheung again through AI.

Tong Jili : Because we have cooperated before, but it is impossible now. But when AI technology matures, nothing is impossible.