Mass noun equivalent of 'music' for 'movies'

There are metonyms like '[the] cinema', 'the silver screen', which are often used in non-count usages.

From BBC Bitesize:

• American culture and society underwent a period of great change between 1910 and 1929 due to the popularity of the cinema, silent films, talkies and the impact of jazz music.

Obviously, this is not an exact synonym for 'films/movies', as one wouldn't use it for one's home collection of DVDs (I can prove they still exist).

One can use the plural-form films (and movies) in non-count ways:

• 'Watching films is my favourite leisure activity.'
• *'Watching three/several/21 films is my favourite leisure activity.'
• 'I'd love to appear in films.'

• [New York] is also home to some of the world’s finest hotels, and it is no surprise that some of them have made it onto the silver screen. Here is a list of some Oyster.com favorites that have appeared in the movies....

[Oyster.com]

Both 'She never did appear in films' and 'She never did appear in the movies' display non-count but plural-form usages. Interestingly, one always uses the null article, and the other in this usage the definite article. Compare 'She never did appear on television'. 'She never did appear in more than those two early films' has moved to a count usage.

Two common mass nouns are "film" and "cinema" as mentioned above. "Hollywood" has been used but of late, it tends to be used restrictively to indicate the character of American film. A bit further off is the term "the silver screen" or "celluloid" but these seem to be becoming uncommon.