There's a flaw, I think, in the nature of the question: cinema and TV are types of literature. I teach a class called Film Literature. They're not great literature, but literature nonetheless. (Video games, I'll give you, are not literature).
So, you're saying, "Does low-grade mass literature impede or enhance literary studies?" A bit of circular logic, no?
They're all part of the study of literature. Visual mass media influences the mainstream culture in ways unimaginable. Young people are born into it. It shapes their worldview. Students must move through the visual to get to the written. The early visual literature is synthesized into the written literature. You can't distinguish them once they're all swimming around in there together, can you? So, how can they enhance or detract each other? It's like saying what you see detracts from what you hear.
Early cinema influenced the modernists this way. Steinbeck, Faulkner, and Camus were all influenced by silent film and early talkies. Visual rhetoric is very powerful. Cubist painting, for example, lead to much of Faulkner's free-style narration and use of stream-of-consiousness. Lately, mass media has creeped into the graphic novels and fictions of young novelists (e.g., Jonathan Safran Foer's Extremely Loud & Incredibly Close).
For further study, you should read the chapters on the written vs. visual in Annie Dillard's The Writing Life. She says:
The written word is weak. Many people prefer life to it...Film and television stimulate the body's senses too, in big ways...The printed word cannot compete with the movies on their ground, and should not....Why should anyone read a book instead of watching big people move on a screen? Because a book can be literature. It is a subtle thing--poor thing, but our own.
Technological advancements have done more harm than good for the study of literature. I agree that television and film have both brought great things to the world of education by providing visual (and therefore emotional) responses to many subjects that students would otherwise feel mostly disconnected from. The Holocaust, as an example of this, immediately comes to mind. However, on the whole, technology (especially the Internet) in the last ten years has turned our society into one that largely refuses to think for itself. Students today expect instant answers in 25 words or less. They communicate with others in the form of status updates and would rather Google a question and copy the answer than ask a human for help or, God forbid, come up with something original. Students today constantly ask, “Why read when I could just watch the movie?”
When utilized by a free thinking society that desires knowledge, technology can be a very powerful tool. Unfortunately, the masses of its users have reduced themselves by relying on technology to think for them. As a child, books were one of the first things to which I was introduced as a mode of “escape” and a exercise for my imagination. I fear TV, movies, video games and the Internet are causing a general loss of attention, creativity, and ability to imagine in today’s youth.
On some levels, technology driven mass culture forums have helped to enhance literary studies. Blogs, forums, and sites devoted to specific literary studies have helped to increase affection and appreciation of critical works. In a literary study landscape that has been defined by niches, the world of technology has helped to further this sense of definition in its creation of multiple arenas where this specialization can happen. At the same time and like all technology inquiries, it becomes essential that the modern thinker is able to distill the validity versus lack of it with these particular forms of expression. The lack of an overall authority figure can represent both a point of liberation or inhibition, given some of what is out there. If anything, it requires a very conscientious and considerate thinker to be able to find true appreciation of literary works and studies of them.
I think that technology has definitely enhanced media. We have more options, we are able to look at things in a broader perspective. Film is one genre, but I think it is also important to consider other elements of technology such as the use of hypertext to layer a story (fact or fiction) as well as the ability we now have to reinvigorate the past. Electronic access to many different works of literature, for instance, as well as copies of original works scanned electronically have advanced our ability to do primary research. Film has allowed us to reinvent classic tales in a new way. All in all, we have definitely had our horizons broadened by the media!