The chinese can learn cinematography from the soviet, plenty of american hollywood actually inspired by the soviet cinematography, for example lord of the ring battle scene got inspired by alexander nevsky. the reason i cited soviet film is because they are free and good in general, no need to pay or pirate them. The soviet film influenced cinema in general (from battleship potenkim to tarkovsky film, etc.)
that's why I said established institution to specifiy about experiment, when in come to lining up, private studio can learn from the experiment and make film to cater general audience. The soviet in general make good art film, film that the purpose of the film is art not to cater general audience.
Also technology while matter, it isn't everything alexander nevsky (1938) by sergei eisenstein still widely studied even though the costume is made from cardbox. That's why i said make instituion specify to learn about filmmaking and creating experiment, it's like research institution but for film and entertainment. The private studio can take care when in come to popularity.How would contacting old Soviet filmmakers, depending on how many are left, help when they themselves have hardly contributed much to modern Russia's own film industry? Plus its not like people around the world were lining up to watch Soviet movies the same way they did for The Godfather.
Regardless of who China learns from, be it Korea, Japan, or America, the most important thing is the country needs to up its production values and write better scripts. The former will take a while since its an issue with technology.
As for lining up, western director widely study soviet film and praise them. Hell george lucas went as far as saying soviet artist has more creative freedom and akira kurosawa literally said the soviet film prevent him from suicide.
What i want to say is china should combine the strength of hollywood and soviet. Hollywood strength is in term of marketing, distribution and making popular culture while the soviet strength in term of cinematography and film technique